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Old 11th June 2019, 20:41   #1
Tourist
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Default Aircon Condensor O-Ring Sizes

Hello All,


I've got a bit of a job on tomorrow, after a very successful trip to the scrapper today. I found a 65k mile car identical to mine, same trim spec, colour, engine etc., only 490 cars later on the production line.


It yielded a wealth of handy parts, but most specifically the front radiator/intercooler/condensor assembly to replace the bent items on my car that I mentioned in another thread. I also finally found a replacement rear bumper in the right colour, with parking sensors :-)


Tomorrow I'm taking the front bumper and other bits off my car to swap the parts over, but I gather that replacing the O-Rings for the AC pipes into the condensor is not a bad plan to guard against leaks. There are quite a few AC specialists locally so hopefully if someone could be kind enough to tell me the sizes I need, I can purchase them before I take the car apart.


One other question - is there any way to tell if indeed my AC system is empty? The AC has stopped cooling and when I took it in 2 years ago to get the AC regassed it was apparently empty so I suspect it must be again, but if I can't be sure the best thing is probably to take it to a specialist and have it evacuated.


Cheers for any help :-)
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Old 11th June 2019, 22:04   #2
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... I gather that replacing the O-Rings for the AC pipes into the condensor is not a bad plan to guard against leaks.
That's true Simon but I have done the unthinkable! I re-used the existing 'O' rings when working on my Citron C3's condenser and compressor. Guess what? Yes, no leaks!
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... if someone could be kind enough to tell me the sizes I need ...
Wishful thinking I'm afraid. They're selected by part number or application, not size.
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... is there any way to tell if indeed my AC system is empty?
You can briefly depress the schrader valve on either of the refrigerant lines but take measures to protect your skin in the event that the system is still under pressure.

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Old 11th June 2019, 22:43   #3
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Thank you Simon - very useful info :-)


I'm in a quandry now - I know that my system leaks slowly, but I don't know where from. If it's either of these joints then re-using the 15 year old seals ain't going to help. The leak could be elsewhere though, I know. It could even be in the current condensor - I've no idea what condition it's in until I get the bumper off and take a look.


Hmmmm.


I shall sleep on it I think, and work out what to do.


One other thing - people have talked about lubricating the O-Rings with rubber grease. I'm guessing this may help to seal the joint. Where does one buy rubber grease from?


Thanks again!
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Old 11th June 2019, 22:54   #4
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Thank you Simon - very useful info :-)

One other thing - people have talked about lubricating the O-Rings with rubber grease. I'm guessing this may help to seal the joint. Where does one buy rubber grease from?
Thanks again!
Hi

I can't help with O ring sizes, but I know Wheels in Motion here in Stevenage sells small tubes of Rubber Grease, so I guess Halfrauds, Euro Car Parts or other Motor Factors will do it.

Cheers

John

PS. Re my PM .... which scrappy did you visit?
PPS. Good luck!
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Old 11th June 2019, 22:54   #5
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Originally Posted by Tourist View Post
Thank you Simon - very useful info :-)


I'm in a quandry now - I know that my system leaks slowly, but I don't know where from. If it's either of these joints then re-using the 15 year old seals ain't going to help. The leak could be elsewhere though, I know. It could even be in the current condensor - I've no idea what condition it's in until I get the bumper off and take a look.


Hmmmm.


I shall sleep on it I think, and work out what to do.


One other thing - people have talked about lubricating the O-Rings with rubber grease. I'm guessing this may help to seal the joint. Where does one buy rubber grease from?


Thanks again!
You won't need loads Simon, so how about THIS

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Old 11th June 2019, 23:17   #6
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Thanks for that chaps. Looks like rubber grease is less unusual than I thought. How can you make it to 40 years old, spend probably 25 of those messing with old cars and not notice rubber grease for sale in motor factors. It's one of life's little mysteries I guess.


The car's been a lot nicer since you re-mapped it Brian - I took the bumper off the other evening which was when I found that the intercooler and radiator were bent. Bending them back as far as I dared and re-seating the plastic pipe has reduced its smoking habbit a bit, but tomorrow's efforts will hopefully finish the job and I'll find out just how much better it drives with the re-map.


Annoyingly the car in the scrapper today also had a fractured EGR valve bracket so mine's still cable-tied at the mo. That's a job for another day!


Cheers for now!
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Old 12th June 2019, 06:41   #7
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Hi Simon, Jules supplied me with most of the O rings for the a/C. He does post.
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Old 12th June 2019, 08:49   #8
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I know that my system leaks slowly, but I don't know where from. It could even be in the current condensor ...
The first thing to say is that if you haven't been using your air conditioning regularly all the year round (at least once a month), the seals will slowly dry out and refrigerant will be lost. The answer to this is to get it recharged and use it!

Also, your system should have dye in it Simon. This appears as a luminous green/yellow colour to the eye but a small leak may require detection equipment. You're right to say that the condenser is most likely to be the problem.
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I shall sleep on it I think, and work out what to do.
I suggest that you find an independent (and mobile ideally) self-employed practitioner who only does air conditioning. He will have the equipment to locate your leak.
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... people have talked about lubricating the O-Rings with rubber grease.
I would definitely not do that for the following reasons. In my experience, these 'O' rings do not normally require lubrication. The union is of similar construction to brake and high pressure oil lines and there is virtually zero risk that the 'O' ring will deform. If lubrication is used, the workshop manuals specify a smear of refrigerant oil. You do not want even the smallest amount of rubber grease entering your air conditioning system where it could cause a malfunction.

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Old 12th June 2019, 18:17   #9
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It's true to say that I've not been using the AC very much over the winter, but then I've not been driving the car very much at all since I changed jobs back in July last year. My morning commute now takes place on two wheels in all weathers.


One of the reasons I'm undertaking this work now is that we're off to Scotland at the end of next month so I want it right for that - both the Aircon and also the performance/intercooler.



I had planned to swap the radiator / condenser etc., assembly but it's been raining all day so in terms of working on the car, I only had time to replace the rear bumper, which has made a huge difference to the visual appearance of the car, and my parking sensors work again.



Simon's advice to briefly depress one of the the Schrader valves on a coolant rail showed me that the system was still under pressure, although I don't have any way to know if it was under enough pressure to allow the compressor to kick in. I suspect not. With this in mind, I mananged to buy a Groupon deal for a cheap AC regas at ATS Euromaster, and they've emptied the system for me this afternoon. As soon as the O-rings that I've ordered from DMGRS arrive I can get on with that bit of work.


Here's a photo of the car with the new rear bumper (and bonnet for that matter) after I washed it just now. It looks a lot better than it ever has i nmy ownership.


IMAG1589 by John Doe, on Flickr
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Old 12th June 2019, 21:28   #10
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Lubrication can be applied sparingly of course, only as much as required, i.e. not slathered on in great gobs.

PAG oil must NEVER be used to lubricate O rings, as this will cause corrosion to form at the joints, both causing leaks and making subsequent dismantling troublesome.

Instead a standard mineral oil can be used, or indeed as you have already heard rubber grease, neither of which will cause a problem.

The main type of joint employing an O ring in the A/C system is that of a parallel flange, so completely unlike both the taper joints used in hydraulic systems, and the flare nut unions employed in fixed brake lines.

PAG oil is very hygroscopic, so you will want to have the system either recovered before you start, or left open for the least amount of time if it's already empty, and the person who recharges the system must vacuum the system, both to test for leaks, and to remove any contaminated PAG oil, which will damage the system due to acid formation.

The oil grade is PAG46 and the dry fill quantity is 120cc with 450 grammes of R134a

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