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Randy Roberson
Grand Master
Username: wascator

Post Number: 452
Registered: 5-2009
Posted on Sunday, 21 June, 2015 - 10:58 am:   Edit PostDelete PostView Post/Check IP

Hi, can an experienced repairman (like Bill Coburn, for example)suggest a good starting point for setting the length of the height control valve links? I think I have my Car's links set too short to get any action. I have not really tried to set them as I have been making other maintenance and repair tasks. I think I stopped the last known leak today, and I need to set the links so I can see if the height system will do anything.
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Robert Noel Reddington
Prolific User
Username: bob_uk

Post Number: 159
Registered: 5-2015
Posted on Monday, 22 June, 2015 - 04:29 am:   Edit PostDelete PostView Post/Check IP

Caution. The arms on the ride control valves must not be turned too far because the little thingy inside can become disconnected. And then the valve will have to be dismantled to reconnect.

On the trailing arms are vertical slots to which the link is bolted to if the nut is undone then the link can be moved in relationship to the ride height. If the link is moved to the very top of the slot then the valve should open and jack the rams up.

If a 4 post lift or pit is available then so much the better. If not axle stands under rear hubs. Be careful.

If your car has good rear springs then the valve should be shut. If they have sagged a bit then adjust the slot so that the sill trim is centre of rear wheel when the rams jack up.

The links length were set at Crewe. Obviously. This once set is not a service adjustment because of the slot. So at first assume that the length is correct.

However previous owners may have mucked about with it.

So go to workshop manual hydraulic chapter. The ride valve insidy bits are shown including the thingy bit that falls out. This will show the middle position of the arm. From this its possible to figure out if the links length is wrong. Also the length may be stated because I suspect that all Shadows have the same length links. Though I know the valves were moved around early on.

If the height system is working then by loading and unloading the car the system can be exercised. Believe or not most ride height systems are still working fine.

Depending on year the fast solenoid valve is checked by ( on my car 1974 17768 in park) to activate the fast solenoid. This looks like an ignition coil. It should click. If it clicks then its probably working. If not connect test lamp to the 2 feed electric wires. If no power then its fault find time. If power is present then the valve is faulty. Again these generally do work. The fast solenoid is not really needed but nice if it does work. The fast solenoid can be overhauled.

2 other bits that you may want to check. On the rear cross member are 2 tee piece looking unions. These are restrictors. Inside is a disks and a roller. The testrictors can build up sludge and become a bit to restrictive. This can cause the front rear calipers to snatch. The rams are jacked up a bit the rear wheels hit a bump the pressure goes up in the rams and because it can't flow properly due to sludge in the restrictors it pushes the front calipers on. Also these restrictors are in circuit with the fast solenoid.

The restrictors are shown in detail in the workshop manual. Take photos of pipe layout before removal.

Bleeding the rams. The rams have 2 pipes each. Ones is a feed the other is the bleed pipe and has a pink sleeve for id. The pink pipes go to a block under neath on the inside of the sill. This block has bleed nipples for the rams. To bleed pressurise no 2 system by running engine then load boot with sand bags or water drums. Then open nipples.

My car has nipples screwed directly into the rams do to bleed I lay in the boot and open up the nipple.

The car should drop as the nipples are opened. Shut nipples allow car to jack up the rams then repeat. Twice will do. As the car is used air any air will finds its way back to the reservior. Any air in the ride height system will not interfere with the brakes.
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Randy Roberson
Grand Master
Username: wascator

Post Number: 454
Registered: 5-2009
Posted on Monday, 22 June, 2015 - 06:21 am:   Edit PostDelete PostView Post/Check IP

Thanks! I admit I am the chap that mucked about with them. When I overhauled the control valves everything was so nasty I had a good fit of housekeeping. I have Her rear up on two plastic ramps to enable access. I know She has a bit of sag in the bum but after 45 years I understand.t
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 1414
Registered: 6-2009
Posted on Monday, 22 June, 2015 - 06:37 am:   Edit PostDelete PostView Post/Check IP

Randy,

If you don't have a copy of, Flush and Bleed Your Silver Shadow/Bentley T Hydraulics/Brakes the Easy Way, then download it and have a look. I discuss (and include the figure from the Workshop Manual) how far you can hand push the height control lever on the valve before internal disengagement. Unless you're really ham-handed that's quite unlikely and the system responds long before you're anywhere near to the degree of deflection from center where disengagement occurs.

If you've got enough sag that you need the height control rams to compensate you may want to consider rubber spring spacers instead to achieve the correct standing height. I've documented those (and recently had to recheck the links to them) in my RR & Bentley Parts, Repair, Restoration & Other Resources Compilation.

If you've got the rear of the car up on ramps you can very easily test the valves by hand. When I took the hydraulics seminar at the RROC-US/RRF headquarters they put the car up on a drive-on ramp and tested the function of the height control valve by popping the control arm off of the post it attaches to and giving a slight push up then a slight pull down with the corresponding up and down motion of the car.

Brian
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Randy Roberson
Grand Master
Username: wascator

Post Number: 455
Registered: 5-2009
Posted on Monday, 22 June, 2015 - 07:47 am:   Edit PostDelete PostView Post/Check IP

Hi, Brian, I do have a copy tucked in my e-file.
As for rear spring sag, when compared to the '77 Wraith II, the 1970 Silver Shadow is noticeably lower in rear; however, the chrome strip trimming the lower body about centers the wheel cover emblem when I sight down it.
As for the function: this afternoon I removed the transmission gear selector thermal relay and started Her up. On the left side of the Car I have one leak to go; oh, well, at least fluid is flowing. Also, when I turn the ignition switch ON, I can hear the height control fast-slow solenoid click (which is reassuring as I had it completely apart on my kitchen table last winter).
When I disconnected the lower end of the height control link on the left side and pushed up, nothing happened, nada. When I disconnected the link on the right side and pushed up slightly, up she went, and quite smartly. very exciting. That is the first time I have seen any action from the height control system.
Now, to determine why the left side did not react.
Thanks a bunch, Bob-Robert.
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Robert Noel Reddington
Prolific User
Username: bob_uk

Post Number: 160
Registered: 5-2015
Posted on Monday, 22 June, 2015 - 08:05 am:   Edit PostDelete PostView Post/Check IP

Please take care be aware that operating and moving the rams could destabilise the car.

Sometimes I put one ramp in back to front. So it cannot roll off. In park hand brake on.

If you examine the links you may be able to discern where the lock nuts were on the links threaded rod bit. They were there for 40 odd years and probably have left a trace.

With out looking at the drawings I think the valve arm is in the middle when horizontal with about 15 degrees angular movement either side.

An advantage of saggy springs is that the ride height is continually operating. Thos excercises the system. Hydraulics like to be used. The aero plane guys are parnoid about inactive aero hydraulics.

There is a misconception ( not on this forum because we know ) that running the car on the rams will damage them. This is obviously not true. Simply because what happens if the car is driven with 5 people and luggage from Scotland to Monte Carlo. And the rams aren't made of liquorice. Good quality robust steel.

If the rams do leak then as to enable the car to be used. Simply disconnect the feed to the ride valves at the block ( 1" square aluminum about 1/2 thick.) Just in front of the rear cross member that has the valves bolted to it. And plug with a 3/8 unf brake bleed nipple. This will allow one to sort out the rams at leisure.

Removing the rams is a PITA job because the spring wobbles around and the room is limited however once out the rams responsed well to a piston polish and a kit. Assemble with Castrol Girling red brake rubber Dot compatible grease.

A little trick that may not work but does no damage.
If the rams leak then if a grease nipple is screwed into the ram port that feeds the ram. Not the pink bleed side. Then red rubber dot compatible grease can be pumped in with a grease gun. This will lift the car a bit. Then undo the bleed nipple ( not grease nipple)and the car will drop pushing out the red grease which is dot compatible. Then reconnect ram feed. The hydraulic presure will then carry the grease hopefully to seal up the seals.

Note that I keep saying dot compatible grease. A veggie based grease. Marmite doesn't work. The red rubber grease will dissolve in the RR363. And also bleed out via the pink bleed line.

I have noticed that dot compatible Red rubber brake grease has sealing properties. And also that as mentioned else where RR363 or Yak milk 363 Dot 3 or 4 is much better leak wise than LHM systems.
Castrol Girling Red Rubber Brake Grease is about £7 for 500grams tin. Thats enough to do the calipers on 10 Shadows.
Storage the lid must be kept on and surplus grease not returned to the tin keep away from mineral greases and oils. Like one does with Brake Fluid.

A dab of Chassis mineral grease in the links ball joints.
Note that RR 363 compatible red rubber brake grease is not as good as mineral greases for lubrication.

Again I emphasise Dot brake fluid compatible.

Don't forget to fit new dust covers to all bleed nipples. Also bleed nipples are cheap. So any scabby ones replace with new. Spares are handy.

Two types. The front calipers on my 1974 are M10 fine. The rear calipers and the rest are 3/8 UNF. They are NOT interchangeable.

On my car the ride height valves have a flexible hose in each valve which connects to a metal brake line that goes to the ram. This line colour coded brown. These hoses if dodgy can stop the ride height from working. A simple test is to blow though both ways by mouth and the air should flow easy. And of course cracks and abrasions.

I think you have already changed these hoses.
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Randy Roberson
Grand Master
Username: wascator

Post Number: 456
Registered: 5-2009
Posted on Monday, 22 June, 2015 - 09:20 am:   Edit PostDelete PostView Post/Check IP

Yes all my hoses are changed. It occurred to me: could not bleeding one of the rams cause it to delay working? I only moved the lever for a second or two. If there were enough air in the left ram it might not have had time to push it out while I had the lever up.
Then again, I could have misassembled the control valve.
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Robert Noel Reddington
Prolific User
Username: bob_uk

Post Number: 162
Registered: 5-2015
Posted on Monday, 22 June, 2015 - 09:53 am:   Edit PostDelete PostView Post/Check IP

Good move hose wise fit and forget for 10 years.

The ride valves are the most complicated bit of the Shadow hydraulics. An easy test would be to open the bleed nipples and observe the flow as the link is moved up and down the slot making sure that it does not become disconnected inside.

As far as I can see from looking at the drawings is that incorrect assembly is possible but the drawing is good and if something is hard to put together then maybe its being assembled wrong.
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Randy Roberson
Grand Master
Username: wascator

Post Number: 457
Registered: 5-2009
Posted on Monday, 22 June, 2015 - 11:20 am:   Edit PostDelete PostView Post/Check IP

I think all Her hoses were original: all were marked Girling and 70. The fittings were externally rusty but none leaked.
Biggest problem I had was rusty pipes: they were mot leaking but removing the nut twisted the rusty things right off. I bought many feet of CuNiFer tubing and a sack full of nuts.
I will try the bleed screws and see what happens.
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Robert Noel Reddington
Prolific User
Username: bob_uk

Post Number: 165
Registered: 5-2015
Posted on Tuesday, 23 June, 2015 - 07:41 am:   Edit PostDelete PostView Post/Check IP

I believe the hoses for the rams on my car are original and no good.

Twisted rusty steel brake pipes are about par for the course I just twist them up and replace with cunifer. I dont bother trying to hard to save the steel ones.

Once one has a flaring tool then the cunifer pipes are very cheap.
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Geoff Wootton
Grand Master
Username: dounraey

Post Number: 787
Registered: 5-2012
Posted on Tuesday, 23 June, 2015 - 08:59 am:   Edit PostDelete PostView Post/Check IP

As for rear spring sag, when compared to the '77 Wraith II, the 1970 Silver Shadow is noticeably lower in rear; however, the chrome strip trimming the lower body about centers the wheel cover emblem when I sight down it.

I've always questioned this notion that a line drawn along the lower chrome trim should subtend the center of the rear wheel trim. Certainly wasn't true of my 74 SY1. Checking out photos seems to confirm this. I reckon the line should be 1 to 2 inches above the center of the wheel trim.

Geoff
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richard george yeaman
Grand Master
Username: richyrich

Post Number: 318
Registered: 4-2012
Posted on Tuesday, 23 June, 2015 - 09:32 am:   Edit PostDelete PostView Post/Check IP

Hi Geoff I also think the cars look better sitting a bit higher at the back it gives them a more balanced appearance.

Richard.
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Robert Noel Reddington
Prolific User
Username: bob_uk

Post Number: 167
Registered: 5-2015
Posted on Tuesday, 23 June, 2015 - 09:59 am:   Edit PostDelete PostView Post/Check IP

I notice that the worshop manual doesn't use the sill trim method. It uses 2 fixed points and their differences at each wheel.

In view of what Geoff has said I would suggest that the first check must be performed as per worksop manual and corrected as necessary. Then measurements taken from the sill trim and recorded. Once set it should last for years.

The idea of the wheel centre being in line with the sill trim is an attractive idea because it seems obvious or intuitive.

I think I shall check my car the proper way. I imagine the front will be correct the rear is bound to be wrong.

I think that correct ride height minimises tyre wear and maybe even strain on the suspension joints

My theory is that it's not possible to have suspension that moves exactly as the designer would like. And that because the car rolls the angles to the road change. The designer arranges things so that as the car rolls the camber changes to keep the wheel perpendicular to the road. If the ride height is wrong then the cambers wrong after that it gets complicated.Because the angle of the rear trailing arms.
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Randy Roberson
Grand Master
Username: wascator

Post Number: 460
Registered: 5-2009
Posted on Wednesday, 24 June, 2015 - 12:15 am:   Edit PostDelete PostView Post/Check IP

I read up on checking the height last night: seems that one measures from a bolt at the rear subframe-sill mount forging to the floor, and from the lowest of the four bolts at the inner side of the other end of the subframe, and the acceptable difference is 5/8 to 7/8 inch lower at the front bolt than the rear. This I will do when I get her off the plastic ramps.
I am not too concerned with setting the height until I get the left-side leveling system moving. The right-side system worked very nicely, plus there has not been any evidence of leakage from the ram, so far (and that's not very far, I admit, but one can always hope).
I did open the bleed points for the rams: the right side bled well; just a drop for the left, non-working, side, but it did appear to be clean fluid and not gunk. I have a leak where the piping connects to the high-pressure supply: you know, the hose that is braided steel rather than rubber like the return hose just beside it. I think the pipe was just too rusty and is maybe cracked under the nut, or otherwise not sealing. That's OK because I have a 3/16 compression union ready for it.
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 1418
Registered: 6-2009
Posted on Wednesday, 24 June, 2015 - 03:04 am:   Edit PostDelete PostView Post/Check IP

Randy,

Is your car set up with three hoses coming from the left side height control system or with four?

I am sure someone will correct me if I'm wrong, but I believe that Crewe actually did away with using that braided steel high pressure hose in the height control system. It's definitely not present in the two-series cars, and I believe that's "hose number four" on the earlier one series cars. I know the change occurred before the two-series, but cannot for the life of me recall what chassis number and have no idea how this would be designated in the booklet that shows changes during the production run.

In any case, when I was researching this about six years ago now my final chart for the hoses indicates that even for the 4-hose layout that none of the replacement hoses is a high-pressure braided hose.

Brian
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Robert Noel Reddington
Prolific User
Username: bob_uk

Post Number: 169
Registered: 5-2015
Posted on Wednesday, 24 June, 2015 - 06:00 am:   Edit PostDelete PostView Post/Check IP

My car 17768. Has no front rams.

There are two hoses one rubber and one braided. Feed and return.

The cars with front rams had 3 hoses
1 return 1 feed and 1 signal pressure from the fast solenoid valve to the front rams. I think that's right.

The top rear port of the ride valves also has a rubber hose each side.

So 3 rubber and 1 braided. All the others are brakes.

The 3 rubber ones are suspect on my car.

All the brake ones are good.

Fortunately when a Shadow is left idle the rams retract in to a cylinder that has RR363 in it. So the piston gets protected.
Fingers crossed.