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Old 28-09-21, 05:37 PM   #1
Hanuman
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Default Aircon gas conversion questions

I have 3 V8s.
The 1990 and 1991 cars with the older aircon system are both original R12 spec. Both need to be recharged.
The later 1993 car was Dealer converted to R134, but there is little information about what this entails. Is it possible to simply use later gas with few problems?

if anyone has been down this route, id be glad of your input.

Secondary question
The earlier type of compressor. My 1990 had a compressor clutch failure. Lots of smoke, noise, fumes. I ended up parking the car for a while as I couldn't get a tool to pull the clutch off. It appears to be M24x1.5 thread. Supposedly, clutches are easily obtained.
I've now swapped in a complete spare used compressor, and the car is sort of running again,
although I also have a brand new unit still sealed in a box.
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Old 28-09-21, 07:39 PM   #2
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On my V8 it already had a R134 conversion which is simply adaptor for re-gassing
The problem with R12 compressors are, they do not hold R134 as long as they do R12.
My one is out of gas now, so I think to open the compressor and change all seals to green ones (kind of R134 compliant) and fingers crossed it will do the job for longer.
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Old 28-09-21, 09:20 PM   #3
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From what little I have gleaned so far, the gas leak down is the main and obvious problem. But there’s a lot more seals than just in the compressor.

I have a brand new pump for the older cars. As it was new only a few years ago (2016) I would imagine that it should be R134 compliant at least.

Now, I heard from an aircon service a short while back that even R134 is superseded. Or to be.
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Old 29-09-21, 07:00 AM   #4
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Is Klausy still around and doing this ? He was down your way ish, autoaircon if I remember correctly
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Old 29-09-21, 08:07 AM   #5
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Who? What?

If you have any information, contact details, I'd be grateful.

I'm off for winter hibernation shortly. So nowt will be accomplished over the next few months, but then it's not really the weather for it.
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Old 29-09-21, 08:37 AM   #6
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Quote:
Originally Posted by Hanuman View Post
Who? What?

If you have any information, contact details, I'd be grateful.

I'm off for winter hibernation shortly. So nowt will be accomplished over the next few months, but then it's not really the weather for it.
I’ll pm you.
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Old 29-09-21, 09:35 AM   #7
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https://www.s2forum.com/forum/member...sion-r12-r134a
This company in Lymington maybe useful?
https://automotivecompressor.co.uk/

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Old 29-09-21, 10:29 AM   #8
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reading with interest...
I have to fix the aircon in my car. I have three compressors with brackets, two underbonnet/scuttle intakes with evaporators and three condensors along with assorted wiring/sensors/fans.

It is a winter project to be ready for summer, so not urgent, but will be nice to have it avaialable on hot days.
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Old 29-09-21, 02:23 PM   #9
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R12 is now illegal so you won't get that anywhere.

R134a requires new seals to be used in an R12 system but you'll probably need to replace the drier.

There's a new R134a replacement - don't know anything about it.
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Old 29-09-21, 03:35 PM   #10
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After doing some further research...

The R134A alternatives were also phased out as they had, as I understand it now, some proportion of R12/freon.

Accord to some initial blurb that I've read, molecule size leads to increased leak down rates. Which with a system that has been run down already may be further exacerbated.

The oil used for R12 is not directly compatible with R134A in that it doesn't readily mix, and therefore doesn't transit the system, but some folk have simply added the normal service amount of R134A-oil to the system, and the appropriate quantity (by mass) of R134A gas. This lead to system problems in some cases as the overall pressure is lower. Later pumps provide a higher output. A part of the original service change was to swap some pressure sensors. A fudge/fix has been to add the appropriate amount of R134A gas, plus a bit more. How much is a bit more? 10%? lick finger, place in airstream...

If the system pressure is too low, then the pressure sensor doesn't activate, and the controller doesn't activate the clutch, and so the system doesn't get cold. I've yet to delve into the diagnostics on this. That'll be for next spring, now.

Parts
Green o-rings.
I'm disinclined to rip everything apart unless I really must. Reports from some sources suggest they've got away with it. The easy ones to swap will be pump inlet outlet, drier, radiant a small few others. 7-Zap hopefully will lead me to these.

Pump seals.
I've one brand new pump. At a suitable point, I may swap it in along with a few other bits, but for now, i'll see what I can get away with.

Pump.
I actually have accumulated a spare of each type of pump. They're not interchangeable on the V8s. the early car plumbing ('90 and '91 models) at the pump is very different to the later pump. Again, I may take a moment one day to work out if the later plumbing can be swapped in. In this case, it will likely negate the need for the new pump!

Nozzles.
Apparently, these are different, as the hoses/fittings for filling up the system changed between R12 and R134A. Larger later, I think. I have spare bits and pieces of plumbing from the scrapped V8, plus somewhere I picked up a few bits for the upgrade.

Tools
The only thing I've encountered as a problem at present is the Aircon service tools that I acquired a while back don't include the correct puller for the '90 car's Aircon clutch. Right diameter, wrong thread. As far as we've got so far, it may be M24x1.5 thread. Loads in the states and Germany.


...and that's as much as I've been able to glean so far.
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