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Brian Vogel
Grand Master
Username: guyslp

Post Number: 704
Registered: 6-2009
Posted on Friday, 10 January, 2014 - 08:07 am:   Edit PostDelete PostView Post/Check IP

Hello All,

The thread on this regarding the SZ cars and a recent annoying development on SRH33576 prompts me to post here since the photos on that thread suggest that there are some significant differences.

My wipers have decided to become wonky again about parking. I had this problem in the past and had taken the motor cover off and cleaned things off, but it's back again. This time I'd like to be more targeted in getting the wipers to actually park. What they're doing now is staying in position on the windshield at their normal low end of travel rather than parking.

Also, the intermittent function has been highly irregular, generally not working but operating just like the normal slow setting, ever since I bought the car. It will work every once in a while, but even then can "change interval" several times if left on intermittent setting for any period of time.

If anyone has guidance to offer about solving either of these issues (and/or whether there might be any relationship between the two) please share.

Brian
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Jeffrey McCarthy
Grand Master
Username: jefmac2003

Post Number: 424
Registered: 5-2007
Posted on Friday, 10 January, 2014 - 12:15 pm:   Edit PostDelete PostView Post/Check IP

Brian, if you PM me with your email address I'll send you a copy of the article I wrote (with extensive photos) of the whole system. Cheers, Jeff.

p.s. I'm happy to do that for anyone else who'd like a copy as well.
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Jeffrey McCarthy
Grand Master
Username: jefmac2003

Post Number: 425
Registered: 5-2007
Posted on Sunday, 12 January, 2014 - 12:08 pm:   Edit PostDelete PostView Post/Check IP

Brian has kindly converted the article from Microsoft Word to PDF format
application/pdf
Maintaining and repairing the Lucas 16W wiper motor.pdf (470.8 k)
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richard george yeaman
Prolific User
Username: richyrich

Post Number: 148
Registered: 4-2012
Posted on Sunday, 12 January, 2014 - 09:23 pm:   Edit PostDelete PostView Post/Check IP

Jeffry and Brian, thank you for sharing this very well prepared article. I am sure that it will be invaluable to the future well being of these contrary fiddly self minded afflictions!!!

Richard.
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 706
Registered: 6-2009
Posted on Monday, 13 January, 2014 - 10:31 am:   Edit PostDelete PostView Post/Check IP

Jeff,

My deep thanks to you for sharing this article.

Today was exercise day for SRH33576 and I observed two "wiper parking related" things that may help you to help me pinpoint what might be wrong. I have read the article as well.

When I last ran the wipers they had stopped up on the windshield in their "low wipe" position.

Today, immediately upon starting the car, they did the final wipe and park. Later in the drive I needed to use the washer function, and at the end of the cycle they again stopped at the "low wipe" position. After having been turned off for somewhere between 10 and 20 minutes they spontaneously did the final wipe and park.

Does this particular set of symptoms suggest where I should "attack" first? If not, I'll just go through each of the steps in the article. I do not seem to have any issues with slow/fast speeds nor the wiping passes themselves, only the park part of the equation is off and that's not in final parking position, but getting the final park pass to occur when it should.

Brian
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Jeffrey McCarthy
Grand Master
Username: jefmac2003

Post Number: 426
Registered: 5-2007
Posted on Monday, 13 January, 2014 - 11:07 am:   Edit PostDelete PostView Post/Check IP

Brian I was just about to email you but I'll post it here. I think you probably have 2 interrelated problems.

The first is that there are definitely loose connections somewhere. Probably on the motor switches. This is suggested by things waiting 20 minutes to happen. If this isn't caused by the switches on the motor then possibly the dash switch has a soldered connection that failed - not as daunting to fix as it sounds.

The change in speed that you mentioned on the intermittent function could also be caused by a loose connection, lack of lubricant in the wiper boxes or lastly a failing control box.

I'm told though I've never done it that the rack cable can be removed, regreased and replaced fairly easily - I don't know (but I'd like to) if this helps to grease the wiper boxes.

You should definitely oil the spindles as referenced to the Tee One issue in the article.

Keep us all posted on progress as these are issues that all new owners seem to have to face sooner or later.

Cheers, Jeff
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 707
Registered: 6-2009
Posted on Monday, 13 January, 2014 - 01:00 pm:   Edit PostDelete PostView Post/Check IP

Jeff,

How dare you respond in public to a public query!!! ;-)

Truly, one of the reasons I "hang my dirty laundry out" is that I've found we all learn from each others'. It's also amazing how sometimes seemingly completely unrelated problems can provide unexpected insights into each other.

I shall keep the cohort posted. Tomorrow is supposed to be warm and sunny here, so I'll try to dig in to this as much as possible then.

Brian
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Jeffrey McCarthy
Grand Master
Username: jefmac2003

Post Number: 427
Registered: 5-2007
Posted on Monday, 13 January, 2014 - 11:12 pm:   Edit PostDelete PostView Post/Check IP

It's going to be 'warm & sunny' here too - about 41C in the shade! Perfect day to finish my leather projects ... or just drink cold beer inside (a more likely fault :-).

Back to matters though; from talking around and my own experience it is the motor switches & lubrication that cause maybe 80-90% of problems.

The workshop manual concentrates on the dash switch I assume because they took it for granted that checking electrical connectors and grease was something that experienced technicians did first as a matter of course. How times change.
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 708
Registered: 6-2009
Posted on Tuesday, 14 January, 2014 - 07:53 am:   Edit PostDelete PostView Post/Check IP

Alrighty then! - interesting developments today including video with audio, since this speaks more than a thousand words.

I took the covers off the motor, cleaned out the old grease as best I could, then gave things a coat of fresh. Also removed the electrical connectors, cleaned them up, applied a coating of No-Ox-Id A-Special electrical grease, and put them back together. So far, so good.

Now comes the time to do some testing. Though I'm doing this with the car not running the behavior does not change when it is running, so I don't think it's at all related to the motor having only battery power. I'll bet this is what's been going on since this started a few weeks ago, but you can't hear what you're going to hear when the motor's running.

The first video shows the motor running in slow and fast regular wipe speeds, and what happens when you turn it off. The wiping pass stops, but you get this obvious whine that does not stop when the wipers are to park and only goes away if you turn the ignition out of the "Run" position.

The second shows what you get when you use the intermittent setting, which includes a sound not present on either slow or fast, and a repeat of the whine when the switch is transitioned to off between settings.

The wiper arms were on their spindles, but pulled off of the windshield during this test so that I could tell what was happening with both their speed and placement. The whining cannot be explained by the motor having to "work too hard" with wipers on dry glass.

I don't think I can embed video here, so I'll give direct links to the two AVI files. I have no problem playing these in Windows Media Player and I'm sure the Apple Equivalent (Quicktime, I think) should be able to do so as well.

Advice on the next step would be appreciated. I'm guessing that it's going to involve motor extraction, but I hope I'm wrong.

Shadow Wiper Motor Slow-Fast-Off

Shadow Wiper Motor Int-Off-Slow-Off-Int-Off

Connector jiggling changes nothing. Pulling the bottom connector with three wires changes nothing. Pulling the top connector with five wires cuts power to the motor and stops the whine.

The wipers did park normally, but only once. The odd behavior shown in the video is currently the "new normal." When they park, they do not do so any more slowly or with any lack of vigor. This is very strange, to say the least.


Brian
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Patrick Lockyer.
Grand Master
Username: pat_lockyer

Post Number: 880
Registered: 9-2004
Posted on Wednesday, 15 January, 2014 - 08:05 am:   Edit PostDelete PostView Post/Check IP

Sounds like a segment or two of the armature has burnt out.
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 709
Registered: 6-2009
Posted on Wednesday, 15 January, 2014 - 10:13 am:   Edit PostDelete PostView Post/Check IP

Patrick,

Is this something that is reasonable to repair (or have repaired)?

I'm surprised to hear this diagnosis since my past experiences with armature "burn-out" has been an "all or nothing" affair. I had a window motor develop an issue with the armature, and it just stopped dead.

Brian
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Jeffrey McCarthy
Grand Master
Username: jefmac2003

Post Number: 428
Registered: 5-2007
Posted on Wednesday, 15 January, 2014 - 05:24 pm:   Edit PostDelete PostView Post/Check IP

Brian, in the video there is a whining/droning sound when the motor stops. Can you identify where the noise is coming from? It sounds to me like an unusually loud dud relay somewhere - although it could be anything; certainly my motor has never made that noise when it stops.

When I get a chance I'll look at the SII diagrams and see if there's an extra relay (post SI) in the circuit.
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 710
Registered: 6-2009
Posted on Wednesday, 15 January, 2014 - 11:48 pm:   Edit PostDelete PostView Post/Check IP

Jeff,

You're the second person who's given me the relay diagnosis.

I was hoping someone might be able to help me to know where to start in terms of isolating this sound. Though it sounds to me like it's from the motor, that type of noise is hard for me to isolate with my hearing being what it is. It's time to grab the mechanic's stethoscope and start listening to the relays in the area when that sound is happening.

I would love it if this turns out to be a simple relay replacement issue.

Brian
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Omar M. Shams
Grand Master
Username: omar

Post Number: 383
Registered: 4-2009
Posted on Thursday, 16 January, 2014 - 03:53 am:   Edit PostDelete PostView Post/Check IP

Dear Brian,
I am weak when it comes to electrics - but that noise can only be one of two things in my opinion. Either a chattering relay or a servo motor in distress (from the HVAC system).
In my crude way of figuring out what is going on I would pull all the fuses and only put the wiper fuse in its hole to see if the noise goes away. If it stays with only one fuse in, then the circuit you need to look at is the wiper related circuit only. If not, then feel your way with the remaining fuses until you hit the jackpot.
Thanks
Omar
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 711
Registered: 6-2009
Posted on Thursday, 16 January, 2014 - 04:35 am:   Edit PostDelete PostView Post/Check IP

Omar,

While I understand what you're saying, this is occurring with the HVAC system off and said whining stops if you pull the upper electrical supply from the wiper motor. It also occurs exclusively when you turn the wiper switch to the "OFF" position and the wipers are supposed to park.

The likelihood of this issue being HVAC related is slim to none.

Brian
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Jeffrey McCarthy
Grand Master
Username: jefmac2003

Post Number: 429
Registered: 5-2007
Posted on Thursday, 16 January, 2014 - 09:10 am:   Edit PostDelete PostView Post/Check IP

Brian, looking at the SSII workshop manual (M6 p44)

http://rrtechnical.info/SY/TSD4200/m/m2.pdf

there are 2 relays which aren't on the Shadow one. I don't know where they are located but possibly they're the ones visible in your video just near the motor? Being a Shadow 2 and a left-hand drive I'm not sure what's tucked away down there.

The procedure for testing the relays is in the manual.
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Chris Browne
Prolific User
Username: chrisb

Post Number: 131
Registered: 2-2010
Posted on Thursday, 16 January, 2014 - 08:49 pm:   Edit PostDelete PostView Post/Check IP

Hello all,
There are actually three wiper relays on a Shadow 2. On a UK spec car, they are located on the inside of the left hand front wing close to the wiper motor. There is one closer to the firewall and then two one above the other. The single one, numbered 131 in the manual is for normal operation. The upper one, numbered 122 is the park on screen relay and the lower one, numbered 130 is the park off screen relay. Presumably park on screen is when the wipers stop on screen between sweeps when set to intermittent wipe, and the park off screen is when they finally park up after they are switched off. Hope this helps.
Kind regards,
Chris
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 712
Registered: 6-2009
Posted on Friday, 17 January, 2014 - 12:37 am:   Edit PostDelete PostView Post/Check IP

Jeff & Chris,

Thanks very much to you both. The information regarding which relay has which number is most helpful, as I couldn't locate that (or at least hadn't yet) in the workshop manual.

This car started out as a home market car and is, of course, UK spec. I'll have a look at those relays and report back once the snow melts. With any luck this will be over the next few days.

Brian, living through a roller coaster winter
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Geoff Wootton
Grand Master
Username: dounraey

Post Number: 351
Registered: 5-2012
Posted on Friday, 17 January, 2014 - 05:54 am:   Edit PostDelete PostView Post/Check IP

Hello Brian

I have been following this thread with interest as I intend to correct some faults on my wipers just as soon as I come out of hibernation.

My understanding of the wiper mechanism, and I seek correction here from members of the forum, is the windscreen wiper motor actually goes into reverse to fully park the wipers when the wiper switch is moved to the off position. This is mentioned on page M6-7 of the SS-II workshop manual, note 4 just above the heading "procedure for fault 2". Namely,

Carefully move the limit switch outwards to a position where the motor will reverse and move the
blades to the correct parking position.


From the 2 videos, the wiper motor on your car does not go into reverse when you move the switch to the off position and the noise only ceases when you cut all power. Could this be because the mechanism jams when the motor attempts to go into reverse and the noise is caused by the motor spindle skidding round in the worm gear.

For me personally, the next step would be to disconnect the connecting rod and then observe the movement of the gear wheel when the wiper switch is turned to the off position to see if this documented motor reversal takes place.

Geoff.
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Paul Yorke
Grand Master
Username: paul_yorke

Post Number: 1157
Registered: 6-2006
Posted on Friday, 17 January, 2014 - 08:04 am:   Edit PostDelete PostView Post/Check IP

Been away in Ireland repairing cars so I have not been following this - but just quickly -

If you have the older type reverse cam gear then running it too far in reverse will break off the tag and ruin it. If you disconnect the rack from the rod it will not move the switch to operate park.

I would be tempted to say it's a couple of wires swapped over somewhere, probably at the relay or an earth missing.

The same can happen if the tag snaps off the rack. (it's been made stronger over the years.)

When adjusting the park switch It's important to start with the wipers parking high and move them down towards the correct position.
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 713
Registered: 6-2009
Posted on Friday, 17 January, 2014 - 08:06 am:   Edit PostDelete PostView Post/Check IP

Geoff,

I really suspect that binding is not an issue because when things work they work perfectly and when they don't they don't. Also, the weird sound, while pronounced, does not seem to emanate from a motor in distress, which is what was throwing me off a bit (in addition to my hearing being such that isolating the location of certain frequencies of sounds is far more difficult than others - I'd give my eye teeth to replace every electronic-sounding ringer with something that imitates a good, old-fashioned bell).

I will first explore the dead/dying relay theory as I have cured many problems in the past by tracing them to dead or dying relays.

When I last had this issue very intermittently a few years ago I took the cover off the motor and can confirm that the motor does reverse as part of the park sequence, at least if memory serves.

It would have been nice if access to "cheap and easy" video with audio, and the ability to post same, had been available when I last had this stuff apart. Seeing and hearing what's going on is so much better than any attempt to describe same in words.

Brian
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Geoff Wootton
Grand Master
Username: dounraey

Post Number: 352
Registered: 5-2012
Posted on Friday, 17 January, 2014 - 09:45 am:   Edit PostDelete PostView Post/Check IP

Brian

Thanks for the confirmation that the motor does reverse. The workshop manual gives references to this, but does not give a specific description of the operation of the park mechanism. The wipers on my car do not park and have been set to compensate this, so they do not give a full sweep of the screen. I did dismantle, regrease and check for bad connections last summer but this did not cure the fault. Obviously, something I need to attend to.

Geoff.
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 714
Registered: 6-2009
Posted on Friday, 17 January, 2014 - 10:49 am:   Edit PostDelete PostView Post/Check IP

Geoff,

If you remind me later, I will be happy to pop the lid from the motor on the Silver Wraith II and take a video of the park process in action.

I guess there are a few, rare, perverse advantages to having two SY cars at the same time. I'm booked up to my eyeballs tomorrow, so it will have to be sometime after that.

Brian
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Geoff Wootton
Grand Master
Username: dounraey

Post Number: 353
Registered: 5-2012
Posted on Friday, 17 January, 2014 - 10:56 am:   Edit PostDelete PostView Post/Check IP

Brian

Many thanks for the offer. When time permits it would be really useful. I have never seen these wipers park properly on the screen, let alone the actual mechanism in the wiper motor.

Geoff
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 715
Registered: 6-2009
Posted on Friday, 17 January, 2014 - 11:16 am:   Edit PostDelete PostView Post/Check IP

Geoff,

Happy to do it, but I can almost guarantee you that you will need to rattle my proverbial cage about this offer and you should not hesitate to do so.

I'll definitely post the resulting video here for posterity (presuming Google Drive never disappears, which is where this stuff is stored).

Brian
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Bob Reynolds
Frequent User
Username: bobreynolds

Post Number: 61
Registered: 8-2012
Posted on Friday, 17 January, 2014 - 02:28 pm:   Edit PostDelete PostView Post/Check IP

I am totally puzzled by the need to reverse the wiper motor, and also the need for 2 different parking positons. This is surely over-complication for the sake of it.

Is this just a Rolls-Royce thing?

I am not happy with the rather limited sweep of my own Shadow wipers, but surely this is determined only by the mechanical components (cam throw and wheel box pinions) and nothing to do with the electrics.
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 716
Registered: 6-2009
Posted on Friday, 17 January, 2014 - 02:44 pm:   Edit PostDelete PostView Post/Check IP

Bob,

I'm not quite sure what you mean by "2 different parking positions." If you define where the wiper comes to rest when in normal operation at its lowest point of sweep as a "parking position" then I suppose there are two. I just think of the parking position as where the wipers are pulled down to rest when not in operation.

However, I am surprised, nay, shocked, that you are shocked that Rolls-Royce engaged (and probably still engages) in "over-complication for the sake of it." I've used the term "boutique engineering" to denote the same thing (or their penchant for doing something differently, not better, than the rest of the world for a given function).

I can't say that this is "just a Rolls-Royce thing," but they certainly raised it to a high art form.

Brian
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Bob Reynolds
Frequent User
Username: bobreynolds

Post Number: 62
Registered: 8-2012
Posted on Friday, 17 January, 2014 - 05:06 pm:   Edit PostDelete PostView Post/Check IP

"I'm not quite sure what you mean by "2 different parking positions."

Park on screen and park off screen. Apparently there are two separate limit switches for these positions.

What's the point in having the 2 different positions, and what's the point in reversing the wiper motor to park the wipers?
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Geoff Wootton
Grand Master
Username: dounraey

Post Number: 354
Registered: 5-2012
Posted on Saturday, 18 January, 2014 - 01:01 am:   Edit PostDelete PostView Post/Check IP

Bob

This park on screen / off screen was quite common on the older british cars. I used to own a Jaguar XK150 and it had a similar system. I do not know the technical reason for this, but it was a delight to watch the wipers park off screen.

The problem I have with the wipers on my SY-I is the park off screen function has never worked and the wipers are set in the off-screen position. This means when I use them the wipers clear just over half the screen. The sweep finishes just past the vertical position as viewed from the drivers seat. I suspect this isn't an issue to you in the UK as the passenger wiper overlap clears the unwiped driver side. Here in the US where we drive on the wrong side of the road, half the drivers side of the screen does not get wiped as there is no overlap from the passenger side wiper. This is why I need to get my wipers sorted. It was not a problem when I lived in Vegas as it rarely rained, but since I've moved it has become an issue.

Yet another reason why it is better to drive on the left side of the road.

Geoff.
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everythingrollsroyce
Unregistered guest
Posted From: 92.6.168.219
Posted on Friday, 17 January, 2014 - 08:02 pm:   Edit PostDelete PostView Post/Check IP

the area you want wiped is higher than where you want the wipers parked when not in use. so you have a sweep area and a parked area.

on the screen park and off screen park.

the cam has a one way 'clutch' on it so when it turns one way it makes the linkage shorter to move the sweep to the desired area, when intermittent is on you want the wipers to stay ready to sweep again so they wait in the onscreen park possition.

when you turn them off you want them to park lower . the wiprr reverses the one way clutch, swings the cam through 180 degrees and pulls the wipers down slightly further.

the whole sweep equates to about 4cm of rack movement so the reverse cam only changes the throw by a few mm.

most cars use some method to do this to stop the wipers panging against the screen frame on each sweep.

sent from my phone, please excuse any randomness. paul yorke :-)

(Message approved by david_gore)
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Bob Reynolds
Frequent User
Username: bobreynolds

Post Number: 63
Registered: 8-2012
Posted on Saturday, 18 January, 2014 - 07:48 am:   Edit PostDelete PostView Post/Check IP

Ah thank you. That explains everything.

In that case, my wipers are not working properly either!

I don't quite understand exactly how the linkage is made shorter by reversing the motor, but I understand the principle now. Quite ingenious.

In my case, the crank pin appears to be fixed solidly onto the gear wheel, so reversing the motor makes no difference. I guess I must have the wrong motor.
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 717
Registered: 6-2009
Posted on Sunday, 19 January, 2014 - 06:01 am:   Edit PostDelete PostView Post/Check IP

Gentlemen,

As promised, here's the video w/audio of the wipers on my Silver Wraith II (LRK37110) taken with the plastic cover removed.

Since the motor is on the opposite side from the steering wheel in this car, you will hear me instructing my helpful partner as to what speed/switch position I would like to have. You'll also get to see the park process happen twice, once when turned off from the slow setting and the other when turned off from the intermittent setting.

'79 SW-II Lucas 16W Wiper Motor in Action

Brian
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Geoff Wootton
Grand Master
Username: dounraey

Post Number: 355
Registered: 5-2012
Posted on Sunday, 19 January, 2014 - 08:02 am:   Edit PostDelete PostView Post/Check IP

Brian

Many many thanks for taking the time out to make this video. It is really useful to see what the correct operation of this device looks like. I have downloaded a copy for my archive.

Geoff
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 755
Registered: 6-2009
Posted on Tuesday, 25 March, 2014 - 03:23 am:   Edit PostDelete PostView Post/Check IP

Well, now that the weather has gotten at least somewhat consistently better I'm back to this issue.

I definitely have a "chattering relay" but the plot thickens: It doesn't matter what relay I put in as a replacement - each chatters. I have used two different "generic Bosch-type" and one Lucas 6RA and all three give this vibrating/chattering sound. It only occurs when the wipers have stopped "normal sweep" and are trying to park.

I've attached a photo and the chattering one is, of course, the one not bolted down at the moment. It is directly in line with the relay to its right in the picture and the third one is tucked below these two and is centered between them:
Wiper Relays

What I'm wondering, before I start taking them all out, is whether one of the other two relays could fail "silently" in such a way as to cause the chattering relay to chatter. The two generic relays are brand new and I've previously tested the old Lucas one that I'm trying and it does open and close correctly when the coil is energized on the bench.

Any assistance is greatly appreciated.

Brian
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Jim Walters
New User
Username: jim_walters

Post Number: 8
Registered: 1-2014
Posted on Tuesday, 25 March, 2014 - 05:33 am:   Edit PostDelete PostView Post/Check IP

Brian, there are two different functioning 6RA relays so you need to have the correct one to test here. One is a change over,(SRB143 or 146) the other is on/off (SRB111) and they can both be marked 6RA and look identical. Low voltage from corroded connections can cause them to chatter. Are you getting a full 12 volts at the relay?

SRE22493 NAC-05370
www.bristolmotors.com
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 756
Registered: 6-2009
Posted on Tuesday, 25 March, 2014 - 08:08 am:   Edit PostDelete PostView Post/Check IP

Jim,

I'll check the voltage in "the next round." We are supposed to get another significant snow this evening. I hope that we only get the low estimate of 1 or two inches.

I can tell you that the relay that's actually chattering is a changeover relay. After I check that the voltage across the coil (I imagine that's the one that would be causing this problem, rather than the common +12V) I'll look carefully at the other relays. You can see that when I had to touch these things some years ago I affixed masking tape labels so that I could easily read the precise kind of 6RA each one was when I had to check them later. It's mighty difficult to read what's on those cases once they're decades old and covered with light corrosion and medium to heavy dirt!!

Brian
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 775
Registered: 6-2009
Posted on Tuesday, 22 April, 2014 - 07:10 am:   Edit PostDelete PostView Post/Check IP

Well, after a long break I finally got back to this yesterday.

I checked the voltage at the relay coil terminals (as I presume that's what would cause the chattering - if not, please tell me what I should be checking). It's a hair under 12V with the car off after sitting for several weeks and a hair over 14V with the car running.

I got the chattering again, but this time I was present at the side of the car when it stopped and the wipers promptly parked. The chattering was present with the engine off and when running. It stopped while the engine was running.

The chattering relay is a changeover relay.

Does anyone have the "old sub-numbering" scheme for the 6RA relays? Before the SRB scheme the old ones are marked with numbers in the 30K range, if memory serves. I never have been able to find a reference that definitively tells me what the various numbers on the cases of "vintage" Lucas relays mean.

Brian
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Paul Yorke
Grand Master
Username: paul_yorke

Post Number: 1186
Registered: 6-2006
Posted on Tuesday, 22 April, 2014 - 07:32 am:   Edit PostDelete PostView Post/Check IP

C2 Contact 1 common
C1 Normally open
c3 Normally closed
W1 & W2 Windings for coil 1 & 2

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Brian Vogel
Grand Master
Username: guyslp

Post Number: 776
Registered: 6-2009
Posted on Tuesday, 22 April, 2014 - 07:52 am:   Edit PostDelete PostView Post/Check IP

Paul,

Thank you. I do, however, already have this reference. The problem is that these designations do not correspond, at all, to what's impressed into the metal cover.

Two of the three relays near the wiper motor have Lucas 6RA 33307D 12V 3277 on the cover. I am told these are now SRB143, but am not sure. If that's the case, they're simply a common 12V/20A changeover relay that I can change out for a Bosch type. I stopped buying Lucas relays shortly after I bought the car, as the things are over $50 each here. I've not had any issue with using Bosch-type changeover relays in the place of Lucas ones.

What is the difference between an SRB143 and an SRB146, if any, other than the positioning of the fastening tab(s)?

I've put together several different versions of the following diagram to map Lucas pin designations to Bosch-type. Here are two:

Lucas to Bosch Relay Map #1

Lucas to Bosch Relay Map #2

Brian
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Paul Yorke
Grand Master
Username: paul_yorke

Post Number: 1187
Registered: 6-2006
Posted on Friday, 25 April, 2014 - 07:58 am:   Edit PostDelete PostView Post/Check IP

What is the difference between an SRB143 and an SRB146, if any, other than the positioning of the fastening tab(s)? JUST TABS.

The Contact numbers are the telling ones.

Bosch Blue or Brown relays ( I think) have two outputs energised when closed. So the same as a Lucas with C1 C1 C2 W1 W2 terminals.SRB111 On a Rolls it will have a white sticker on with red warning writing to distinguish it from the others. Starter relay.
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Bob Reynolds
Frequent User
Username: bobreynolds

Post Number: 78
Registered: 8-2012
Posted on Friday, 25 April, 2014 - 09:10 am:   Edit PostDelete PostView Post/Check IP

The starter relay is the only one I have seen which has a C4 terminal (that's not to say there aren't others). It is a double-make relay, where C2 connects to C1 and also to C4 when the relay is operated. C1 and C4 are not connected together when the relay is released.
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 777
Registered: 6-2009
Posted on Friday, 25 April, 2014 - 09:35 am:   Edit PostDelete PostView Post/Check IP

Paul,

Thanks. The SRB143 and 146 are both single pole double throw (SPDT AKA changeover) relays with one normally open terminal and one normally closed.

What you describe is a dual make [dual normally open] single pole single throw (SPST) relay. There are also single make SPST relays, but those only have four terminals (only one C1).

I've seen Lucas SPDT relays being used as a simple on/off switch like a 4-terminal SPST. On those there's just an insulating sleeve placed over the C3 terminal.

Brian
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Bob Reynolds
Frequent User
Username: bobreynolds

Post Number: 80
Registered: 8-2012
Posted on Thursday, 01 May, 2014 - 11:10 am:   Edit PostDelete PostView Post/Check IP

I decided to tackle my wipers and motor today, to see if could get to the bottom of this wiper parking mystery and fix my wipers so that they sweep the whole of the screen and then park correctly. I'm pleased to say that, not only have I worked out how the system works, but I have also fixed my wipers which I now realise have never worked properly since I bought the car. It cost me nothing, the only thing that was wrong was that a washer had been replaced 180 degrees out of phase!

Until I read this topic, I wasn't even aware that they were not working properly. I was aware that they were only sweeping half of the screen, but I thought that was normal! Judging by other posts, I think this could be quite a common problem, and many people's wipers are probably not working as they should. It is very easy to assemble the wiper motor incorrectly and create this problem without realising it. If you don't understand exactly how the system works you have a 75% chance of getting it wrong!

I have looked everywhere, and nowhere have I seen the parking mechanism explained properly, so I will try to explain it as best I can. The workshop manual seems to have a completely different mechanism from my 1975 SS1, and it doesn't explain how it works or how to assemble it. My explanation below just covers the mechanical aspect of the mechanism and does not touch on the electrical circuit.

In normal operation, the gear in the wiper motor rotates clockwise and the wipers should sweep an arc of 120 degrees (I know this because the gear has 120 stamped on it!). The wiper arms are adjusted on the screen so that the swept area does not include the parking position. In other words, they sweep the screen without returning to the horizontal position between sweeps. When the wiper motor is switched off, it does not simply stop at the parking position; it reverses first and then stops. This reversal causes the connecting link between the crank pin and the rack to lengthen slightly, thereby pushing the rack slightly further out than normal and pushing the wiper blades slightly further down the screen. This is how the wipers 'Park off Screen'.

The way in which it works is that there is an eccentric disc housed in the connecting link, which has an off-centre hole in it. This hole fits over the crank pin on the wiper gear wheel and allows the connecting link to be effectively lengthened and shortened. In the photos 1 & 2 below, you can see the eccentric turned through 180 degrees and the effect this has on the length of the connecting link. Photo 1 is the normal position of the eccentric when the wipers are in operation. Photo 2 is the position when the wipers are parked and the rack is pushed out slightly further than normal.

So what rotates the eccentric when the wipers are switched off? You will see in photo 3 that there is a pawl that engages in a notch in the edge of the disc. During wiper operation this holds the disc in the normal position shown. When the motor is reversed, a spring-loaded tooth on the top of the disc engages with the D cutout on the washer mounted above it. This then turns the disc through 180 degrees before the wiper motor stops. The pawl on the edge simply rides up out of the notch until the wipers are switched on again and the disc has made a complete revolution back to its normal position. The D washer is shown in photo 4 (along with a further retaining washer and locknut to hold everything in place).

The effect of these 2 ratchet mechanisms is that the eccentric disc takes up one position when the motor rotates clockwise, and rotates to the opposite position when the motor goes anti-clockwise. Therefore, reversing the motor causes the effective length of the connecting link to change, and the wiper blades to sweep a different arc on the screen. It's a very clever mechanism indeed, and I take my hat off to whoever invented it.

Now, it is far from obvious how this mechanism works, even when studying it, as the whole thing goes round the gear wheel at the same time as it rotates on its own axis; and you can't see what's happening because it's covered up. But if any part of this mechanism is installed upside-down or the wrong way round it will not work. The eccentric will remain in just one position and this will result in just one fixed sweep of the wiper blades on the screen (ie. no 'Park off Screen' function). In my case, the washer with the D cutout was installed incorrectly. There are four ways to fit this washer and only one will work. As well as mounting it upside-down, it also has to be rotated to the correct position relative to the connecting link. The correct position is as shown in photo 4, but bear in mind that my car is a UK model with RHD, and I am not sure how LHD models differ. It could be that everything is 180 degrees out of phase with my photos. It's mind-boggling enough to sort out how it works, without having to deal with the possibilities of a mirror image version! But if your wipers do not park properly all you may need to do is to check that the D cutout in this washer engages properly with the spring-loaded tooth below it, and then rotate it to the 2 possible positions to see which one works. It is possible that you may also need to adjust the parking switch on the back of the motor, but this is covered in the workshop manual and other references.

If your wiper motor doesn't reverse to park, then you've got an electrical fault which is beyond the scope of this article! I hope this helps those who are confused about how the wiper parking system is supposed to work.

Wiper Parking Mechanism
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Geoff Wootton
Grand Master
Username: dounraey

Post Number: 383
Registered: 5-2012
Posted on Thursday, 01 May, 2014 - 12:01 pm:   Edit PostDelete PostView Post/Check IP

Bob

Great article - thanks for taking the time out to share your detective work with us. Very well explained. The wipers on my SY1 have the same fault and I intend to repair them this September when I get back home and am reunited with SRX18501.

Geoff
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 781
Registered: 6-2009
Posted on Monday, 12 May, 2014 - 05:18 am:   Edit PostDelete PostView Post/Check IP

Just to close out my story: Short version - bad relay.

All three relays related to the wiper system in SRH33576 were Lucas 6RA/SRB143. I decided after all the other checking that I'd done that it had to be one of the two other relays that I hadn't yet replaced that was the culprit in causing the chattering in the one that I had, so I replaced both of them, too. Problem solved.

I could have been more methodical to determine which of the other two (as I'm presuming it is only one that's bad) was the culprit, but since it was just too simple to replace the two remaining relays I just did that. When I have time I'll pull the relay bases out of their respective "cans" to see if there's evidence of corrosion/burning in one or both of the relays removed today.

For now the wipers are parking just like they used to as soon as I turn the switch off with no complaint from any of the three "supermarket Bosch-type" relays now in there.

Brian
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Geoff Wootton
Grand Master
Username: dounraey

Post Number: 1152
Registered: 5-2012
Posted on Thursday, 07 April, 2016 - 12:35 am:   Edit PostDelete PostView Post/Check IP

I just wanted to put some additional information here and also to help keep this thread active.

The wipers are controlled by 3 relays and 2 control boxes. On my car, a 1974 SY1 they are located under the top roll. The control boxes are for the wash/wipe and intermittent functions.

When the wiper switch is turned off, the wipers will continue until the park on screen position is reached and then park themselves off screen. The park off screen is achieved by reversing the wiper motor. The following extract, by Jeff Young explains how the motor is reversed:

"Wiper relays 122 and 130 reverse the power feed to the motor (each controls one side of the motor feed).

The coil of 122 is controlled by the wiper switch, but it is also latched by the park-on-screen switch in the motor (so it keeps the wipers going till they've completed their stroke even after the wipers are switched off).

The coil of 130 is fed through the "off" contacts of 122 and the park-off-screen switch in the motor, so when 122 switches off it turns 130 on. This runs the wipers in reverse until the park-off-screen switch trips."

Geoff
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 1869
Registered: 6-2009
Posted on Thursday, 07 April, 2016 - 02:28 am:   Edit PostDelete PostView Post/Check IP

Geoff,

Not that this has anything to do with you or what you've said, but with Crewe documentation. It is patently ludicrous to have ever described the parking position as "off screen." It is not off screen in any way, shape or form, it is simply very low on the windscreen.

I have two cars in my current fleet that actually park their wipers off screen and where that description is 100% accurate.

I suspect there has been a lot of gnashing of teeth among the uninitiated who cannot understand why the wipers don't park off screen or who reposition the arms such that they are dragged all the way down to the seal at the lower edge, causing constant stress on the mechanism to be exerted when the wipers park, but park way lower than they're intended to.

Brian, who just looked at the video I'd posted again - having forgotten just what this looks like in action
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Geoff Wootton
Grand Master
Username: dounraey

Post Number: 1154
Registered: 5-2012
Posted on Thursday, 07 April, 2016 - 03:05 am:   Edit PostDelete PostView Post/Check IP

Hi Brian

Yes, there must have been a better way to describe the two parking positions. It's good that you have pointed this out, perchance a future newbie crashing his/her wipers off the screen onto the paintwork every time they parked.

With reference to the "off screen" parking position the manual says to set it, it is just a case of flipping the wiper motor through 90 degrees so you can get access to the adjusting screws on the sliding switch beneath. Well, I've never been able to do this. To flip my wiper motor would require me to remove the entire bracketing that holds the wiper motor. But even then, the wires are not long enough to rotate the motor this much. Maybe the SY2 is different. I suspect when I get round to setting the "off screen" parking position it will be a lengthy process of trial and error, each adjustment requiring the disconnection of the wiring plugs so I can access the adjusting screws. This with the motor removed from it's cradle.

Geoff

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