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Phillip Cyr
Yet to post message
Username: lakeb35

Post Number: 1
Registered: 12-2018
Posted on Friday, 22 March, 2019 - 11:05 pm:   Edit PostDelete PostView Post/Check IP

Hey All,

I'm absolutely DONE with trying to sort out this stupid a/c system. The fan and compressor works when the defrost is switched on.. other than that NOTHING.
My question to you fine folks is.. Has anyone rigged up a simple on/off switch that would bypass all the BS and allow the a/c to only blow and chill at the high setting? That's all I need . I could care less about heating..don't need it. It's warm more than it freezes where I live. BUT, I want to be able to revert the system back to original without issue for the next person who may buy her.

Any and all input on this terror would be greatly appreciated
Signed,
Frustrated in Tulsa (aka Phillip) LOL
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Steve Emmott
Prolific User
Username: steve_e

Post Number: 163
Registered: 11-2018
Posted on Friday, 22 March, 2019 - 11:20 pm:   Edit PostDelete PostView Post/Check IP

Phillip I think you need to explain more and perhaps outline what you have done so far.

Defrost switches are usually for heat to 'defrost' so again not sure what you mean as in what switch.

The earlier shadows air cons were fitted with a suction throttle valve not sure if this carried over to the shadow 11 but many have been done away with meaning the air con will usually just keep blowing lots of cold air anyway.

You say the compressor works so are you hearing the clutch kick in....what has been done re gas checks in the system.....too much more information needed to start logically trying to pin point your issue so explain more what you have done so far please.

The air con function is relatively basic to identify any issue. This can be by just feeling certain pipes and seeing if they are hot on the outlet side of the compressor which would confirm gas is being compressed and then following the piping through its length.

Receiver driers can break down and that can clog up the expansion valve so lots can be wrong that any simple on/off switch would never rectify
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Jeff Young
Grand Master
Username: jeyjey

Post Number: 399
Registered: 10-2010
Posted on Saturday, 23 March, 2019 - 02:06 am:   Edit PostDelete PostView Post/Check IP

Hi Phillip,

The defrost overrides two interlocks: the fan delay thermostat (in the water elbow above the cooling system thermostat) and the lower quantity flap switch (under the steering column on a right-hand-drive car).

If the system only works in defrost then that suggests either the fan delay thermostat has failed, the lower quantity flap actuator has failed, the lower quantity flap actuator rod is jammed or not working, or the lower quantity flap microswitch has failed.

My bet would be on the fan delay thermostat or the lower quantity flap actuator rod.

Good luck with it,
Jeff.
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Jim Walters
Prolific User
Username: jim_walters

Post Number: 218
Registered: 1-2014
Posted on Saturday, 23 March, 2019 - 03:15 am:   Edit PostDelete PostView Post/Check IP

Phillip, the Shadow II requires the factory RH8851 test box to set the servos correctly but you can diagnose a few things without it. From your description, I suspect the 44 sensor in the thermostat housing is faulty. To bypass it, remove the two conductor plug from the right side of the housing directly down below the coolant hose going to the radiator. Take a jump lead and ground the yellow/brown wire from the plug. This will bypass the sensor and should allow the fans to work in all settings and temperatures. Try that test and report.

SRH8505 SRC18015 SRE22493 NAC-05370
www.bristolmotors.com
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Mike Thompson
Prolific User
Username: vroomrr

Post Number: 122
Registered: 4-2019
Posted on Monday, 15 April, 2019 - 04:19 pm:   Edit PostDelete PostView Post/Check IP

How can I tell if I still have a R12 freon AC system? And if you have a R22 system stock up now it is going bye bye 2020.
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Jim Walters
Prolific User
Username: jim_walters

Post Number: 221
Registered: 1-2014
Posted on Monday, 15 April, 2019 - 04:29 pm:   Edit PostDelete PostView Post/Check IP

If converted to 134a it will most likely have quick connect fittings to charge the system. If it still has screw on it's probably R12.

SRH8505 SRC18015 SRE22493 NAC-05370
www.bristolmotors.com
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Steve Emmott
Prolific User
Username: steve_e

Post Number: 228
Registered: 11-2018
Posted on Monday, 15 April, 2019 - 05:51 pm:   Edit PostDelete PostView Post/Check IP

Mike I use electronic sniffers. You may be able to borrow one from an air con garage.



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Mike Thompson
Prolific User
Username: vroomrr

Post Number: 127
Registered: 4-2019
Posted on Tuesday, 16 April, 2019 - 02:11 am:   Edit PostDelete PostView Post/Check IP

Well as the picture shows I have the screw on adapter, R12. I know my 1964 Imperial has R12 and if I remember correctly they have kits that converts the R12 into suitable material to convert the fittings and put in R134a. Other wise you have to clean it all out (or something). And if you look close the metal (wet) looks like it is galvanized.

r12
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Jim Walters
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Username: jim_walters

Post Number: 222
Registered: 1-2014
Posted on Tuesday, 16 April, 2019 - 03:24 am:   Edit PostDelete PostView Post/Check IP

It's aluminum. If it has been open to the atmosphere you need to dry it out with nitrogen then vacuum it down to remove any residual moisture. You should replace the receiver dryer. Don't bother converting to 134a, look for a product called Duracool or an equivalent refrigerant, made from byproducts of natural gas production. It is usually available at regular auto parts stores. Works well in both R12 and 134a systems.

SRH8505 SRC18015 SRE22493 NAC-05370
www.bristolmotors.com
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Mike Thompson
Prolific User
Username: vroomrr

Post Number: 131
Registered: 4-2019
Posted on Tuesday, 16 April, 2019 - 03:37 am:   Edit PostDelete PostView Post/Check IP

Jim Walters (while your'e here)

So you are sure the Wilwood pictured (I guess, in brakes post) and the Wilwood link P/N 260-14244-P 1-1/8" bore will fit right into the rat trap?

In my case on the factory brakes, the calipers are not functional (rusted), the lines are clogged and rusting, the height adjusters don't work and have spacers in the springs etc. If I am going to rebuild a system I want it simple and (in my opinion) a safer system (less to go wrong). I hope you stick around and give me advice, as above, to get me through this. But I stopped all work on the brakes at the moment to make sure of the best method, and had come to the conclusion (with a lot of help) that the way you described is the best way. And that MC is really elegant.
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Steve Emmott
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Username: steve_e

Post Number: 236
Registered: 11-2018
Posted on Tuesday, 16 April, 2019 - 03:42 am:   Edit PostDelete PostView Post/Check IP

I assume Mike you are referring to the metal bodywork underneath the alloy air-con casting.

I agree that does look a galvanised surface.

I know non galvanised panels were used on exterior panels which maybe as a lot of lead loading was required to smooth out exterior joints.

As spot welding was done by hand back then unlike robotics today the gasses given off were cyanide.....hopefully operators were well protected.
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Jim Walters
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Username: jim_walters

Post Number: 223
Registered: 1-2014
Posted on Tuesday, 16 April, 2019 - 04:23 am:   Edit PostDelete PostView Post/Check IP

Yes, see other thread for details.

SRH8505 SRC18015 SRE22493 NAC-05370
www.bristolmotors.com
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Mike Thompson
Prolific User
Username: vroomrr

Post Number: 137
Registered: 4-2019
Posted on Tuesday, 16 April, 2019 - 06:46 am:   Edit PostDelete PostView Post/Check IP

I watched a video and he said you have to get the R12 oil out of the system before you can put in R134a. I was told there is an easier method than taking it all apart. It might work I don't know, none of the fans etc work, an I have not had it running long enough to tell. (I love saying that, had it running.)
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Steve Emmott
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Username: steve_e

Post Number: 238
Registered: 11-2018
Posted on Tuesday, 16 April, 2019 - 04:00 pm:   Edit PostDelete PostView Post/Check IP

I too was always lead to understand from the air con engineers at work that it was important to remove the R12 oil from the system as it reacts with R134a gas.

The compressor oil mixes with gas as it flows through the system hence also important to change the receiver dryer if converting and add the correct R134a oil back. There will always be some residual oil left in compressor too. Just pulling a vacuum will not remove this.

Easiest option though is take Jim's advice and search for an alternative compatible drop in gas.
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David Gore
Moderator
Username: david_gore

Post Number: 3222
Registered: 4-2003
Posted on Tuesday, 16 April, 2019 - 04:40 pm:   Edit PostDelete PostView Post/Check IP

R12 air/con hoses are not compatible with R134a refrigerant due to the high permeabilty of R134a through the standard hose - been there, experienced that.

I now use an Australian replacement equivalent for R12 in my 1993 4WD Toyota called Hychill -30 which is a blend of R600a and R290 hydrocarbon refrigerants and costs half the price of the unsuitable R134a as less refrigerant mass is required for charging [around 30% of the charge required for R134a]. This refrigerant also has the advantage it is compatible with the R12 oil.

More details and technical information/troubleshooting is in the product manual:

application/pdfHychill -30 Manual
HyChill-Minus30-manual.pdf (3171.6 k)


.
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Mike Thompson
Prolific User
Username: vroomrr

Post Number: 147
Registered: 4-2019
Posted on Tuesday, 16 April, 2019 - 05:31 pm:   Edit PostDelete PostView Post/Check IP

Well in the USA it says: "In the United States it is illegal to use a hydrocarbon refrigerant as a substitute for a Class I or Class II ODS refrigerant for any end use other than industrial process refrigeration systems, or retail food refrigerators and freezers (stand-alone units only)." Next?
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 2828
Registered: 6-2009
Posted on Wednesday, 17 April, 2019 - 01:31 am:   Edit PostDelete PostView Post/Check IP

David,

I do not wish this to become an endless back and forth, but I will say that in the US there are few AC technicians who change out hoses on R12 systems when converting to R134a. It was standard procedure in the early days, but it's not now as the difference in leak rate was found to be "not significant enough" to justify doing so as a matter of course. If the R12 hoses are intact, they seem to work fine. (Though I'll be the first to admit that hoses dating from the 1970s have a very high probability of needing replacement anyway.)

I have several cars (including SRH33576) that are R12-to-R134a conversions that use their original hoses and have held the R134a charge for years now. My daily driver, a 1989 Cadillac, is among those.

Brian
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Mike Thompson
Prolific User
Username: vroomrr

Post Number: 159
Registered: 4-2019
Posted on Wednesday, 17 April, 2019 - 07:48 am:   Edit PostDelete PostView Post/Check IP

Brian so how did you solve the R12 oil problem? (I'm betting rebuilt everything.)
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David Gore
Moderator
Username: david_gore

Post Number: 3224
Registered: 4-2003
Posted on Wednesday, 17 April, 2019 - 08:09 am:   Edit PostDelete PostView Post/Check IP

Brian,

Unfortunately, my 4WD hoses are original Japanese Toyota installed when the vehicle was assembled and they leak R134a like a sieve [a recharge is effective for 4 to 6 weeks only].

Same system, same hoses with Hychill -30 no problem.

Added bonus - a recharge is half the price of a R134a recharge.

A "no brainer" for me......especially when there are no new R134a-compatible replacements let alone the unique compression fittings for making a replacement hose available due to the age [typical Toyota off-road vehicle] of the vehicle [26 years].

Mike,

It is time the USA caught up with the rest of the world - to the best of my knowledge there have not been any vehicle fires here associated with crashes involving hydrocarbon-charged air conditioning systems. I suspect this is a consequence of the very low volume of refrigerant needed for the A/C to function effectively.
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 2829
Registered: 6-2009
Posted on Wednesday, 17 April, 2019 - 09:55 am:   Edit PostDelete PostView Post/Check IP

Mike,

I don't DIY AC, I have a local guy do it. I know there must be some way that they evacuate the system of both the refrigerant and its lubricating oil.

The turnaround time was way too fast for it to have been anything like a full system rebuild. I recall, clearly, having a conversation with the tech after the work was completed and asking about having to replace the hoses. It was his comment, along the lines of, "We used to do that as part of the job, but over time it became apparent it was not necessary and is no longer recommended, so we don't now." It was also clear that "not recommended" was coming from the folks who provided the R134a and associated bits and bobs for converting the system. I figure, "If they don't recommend it, and it were necessary, they'd be hearing about it when the AC fails in short order." Shops don't like unhappy customers, and a hot customer can be a very hot customer when they return.

As always, caveat emptor and do your own additional homework on this one, as you are sure to get plenty of "you must replace" as well as "you don't need to" and will need to decide which is the preponderance of evidence and which sources you trust more.

Brian
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Mike Thompson
Grand Master
Username: vroomrr

Post Number: 359
Registered: 4-2019
Posted on Tuesday, 30 April, 2019 - 09:23 am:   Edit PostDelete PostView Post/Check IP

Does the ac expansion valve need to be straight up? As on page C35.
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Paul Matnick
Unregistered guest
Posted From: 67.85.101.114
Posted on Friday, 03 May, 2019 - 12:10 pm:   Edit PostDelete PostView Post/Check IP

Mike,
R12 is still available in the US. The car was designed to use R12.
It works better than R134 in systems designed for R12.
Pressurize with Nitrogen to dry out system and make sure it is leak proof. Pressurize and evacuate three times. You want a dry tight system. Refill non leaking system with R12. In Texas, R134 just won't do it.
Your turn signals
Yes I have been reading your posts
ENJOYABLE
Eliminate all corrosion through out the entire turn signal circuit, and maintain proper battery voltage.
Oh and just wait until you get to the climate control system.
I love what you are doing and we are all here to help.
Paul from New York with SRB17266
Been there done that!

(Message approved by david_gore)
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Mike Thompson
Grand Master
Username: vroomrr

Post Number: 384
Registered: 4-2019
Posted on Friday, 03 May, 2019 - 05:17 pm:   Edit PostDelete PostView Post/Check IP

I guess one can still get R12 from places that have reclaimed it from old cars.

Does the ac expansion valve need to be straight up? As on page C35. I need to get it out of my way, and lay it down, but I don't know if it will work that way.

Paul Thanks for your encouragement.

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