Copper washers and A-C connections

[WGB]

In early January I had my 6.9 aircon rebuilt with a new compressor and most lines replaced. Subsequently it has worked as well as a 134a replacement system usually works in the hottest summer on record.

Last week I had my wheels aligned and noticed poor aircon and a very high idle when the compressor cut in meaning the change-over valve is working well.

It was subsequently re-gassed as a warranty job and the leak was found to be the join on the suction pipe where it runs adjacent to the battery.

They have fitted a copper washer in the joint seal it but said they thought it initially should have been a metal on metal plain joint.

It is working fine and they are waiting to see what happens but obviously new suction tubes are hideously expensive if available at all) and specific to RHD cars.

Any comments gratefully received.

Bill

 

[Styria]

Hi Bill, On the 108/109 models fitted with the original red hoses, Mercedes always used copper washers. I think they may have applied similar fittings on the 116's, but I cannot recall.

On replacement systems with alloy fittings, I do not believe that washers are fitted. As I am not an A/C expert, I can make no further comment. Regards, Styria

 

[WGB]

It worked perfectly until yesterday when the system went flat again.

It has had a green tracer fluid put into it and one of the schrader valves had Green Dye around it.

The copper washer joint was clean and dry.

As I am flying to New Zealand for a week tomorrow night I have left the car with them in the hope that all will be well when I pick it up in 10 days time.

Bill

 

[WGB]

It still has a problem but apparently the leak is not at the aforementioned joint.

Still a work in progress.

Bill

 

[John S]

On a USA list I regularly read, George, a respected member mentioned a product called CryoSeal which fixes problem leaks in airconditiong systems, claiming it was the "only good one to use".

Check out http://acstopleak.com/_wsn/page2.html which should give you enough information to determine if this type of product is worthwhile.

 

[WGB]

Thanks for the info.

 

[WGB]

On a USA list I regularly read, George, a respected member mentioned a product called CryoSeal which fixes problem leaks in airconditiong systems, claiming it was the "only good one to use".

Check out http://acstopleak.com/_wsn/page2.html which should give you enough information to determine if this type of product is worthwhile.

I picked up my 6.9 today where I had left it for two weeks while away visiting the land of the long white cloud with the air-con again fixed.

I asked the fellow about this spray in stuff and he said it was used in Australia for a while and worked quite well but if a hose ruptured or if the system was suddenly deflated the residual in the system would suddenly set hard and create all sorts of problems with removal afterwards.

Bill

 

[WGB]

Well the aircon lasted for two days and it is flat again.

Tonight I went down to my totally dark shed armed with a UV light from my Surgery and believe I might have found one small leak on the suction side.

There is a trace of wet green colour that fluoresces in the small gap between the end of the bracket and the side of the tube where the bracket is connected to the ?suction tube at the leading edge of the compressor bracket and my guess is that there is either a pinhole here or more likely a hairline crack. The tube itself has some superficial corrosion but there is a stress point at the site of this bracket.

I will see what the aircon place thinks of my suggestion.

Bill

 

[s class]

You are having some frustrations with this system - I hope you get to the bottom of it soon!

 

[BenzBoy]

That story is enough to make grown mechanics weep into their beer.
My understanding is that the diagnostic dye is a fluorocene base (spelling?) and that it shows up best under an ultra-violet light. If the techs are checking it during daylight hours it may be possible that there are leaks they are missing. Do you have a UV wand or a dental friend who can lend a hand?
Regards,
BenzBoy

 

[WGB]

It's enough to make a mature doctor weep into his Cabsav but it is only a mechanical system and "will" behave.

I think as the leak may be on the suction side it is probably under relatively low pressure which may be an explanation for little in the way of spray.

It ruins a beautiful car as I like my fresh air cold and from ducts - ah well tomorrow is another day and every day makes a further progress.

Bill

 

[Styria]

Hi WGB, from where I am sitting, that would appear to be a pretty nasty little job to fix. I must have a look at my Gleaming Beauty just to make sure I understand what you're getting at. Good luck with it. Regards Styria

 

[WGB]

It is the pipe that comes from the back of the compressor, runs under the compressor on the motor side and then rises vertically alongside the alternator then turns another right angle and has a rubber pipe that travels to the firewall alongside the cam-cover.
There is a bracket connecting it to the front of the compressor bracket and I would think it is a major stress point as their is quite a stress on the pipe from the unsupported vertical and flexible hose component.

I will remove the hose and get it repaired/rebuilt myself if I have any doubts about their ability - if they leave me a decompressed system.

I will see what eventuates today as I am seeing them after lunch.

Bill

 

[WGB]

Surprise, Surprise - they found the same leak I found.

I have the car back with the A-C depressurised and I will remove the pipework myself and have it repaired or rebuilt by an Engineering friend of mine (See Michel - the Craft has it's uses).

Bill