A/C questions--please help!

Good info. The 507 and 508 do seem to be fine with R134a though, so not sure what they changed in the 5H14.

I had a problem finding a gasket set for the 508 when I recently rebuilt one. There were none in the UK at all so I ordered one from the US and it was wrong. Luckily a "new old stock" compressor came up on Ebay so I used that instead.

I was sceptical anyway whether the large ring seal on the faceplate would ever re-seal properly as the surfaces seemed not to be in sufficiently good condition.

 

The compressor is fine as long as you use Sanden's SP-15 or SP-20 oil.

I haven't opened one so I don't know. However I have contacted Sanden and they do not recommend to run it CCW as it will be very noisy, have a reduced life span and void the warranty.

 

Re NW328 Video, this is very good and answers a lot of the initial question so it looks like you get a new belt on the compressor and get the gas charge checked. From what is on the video it is unlikely u have damaged the compressor but it may be overcharged. As the compressor turns, assuming it does with the clutch energised it is not locked up internally. Will be interested in the final result

 

Yes sure. What I meant was what they changed to make them more compatible with 134a than the 507 and 508.

 

The difference between the two gases is their requirements re the chemistry of the lubricant. R12 lubricants aren't compatible with R134a.
By changing the designations ex factory, Sanden and its clients can very easily distinguish between the older R12 compressors and the current series.

Mechanically, there is no change necessary as far as I know. Whether they have mechanically changed something I don't know but suspect so as the Sanden representative I contacted was very clear about not using the SD5 compressor CCW. He strongly suggested me to use an SD-508.

I have previously converted my Mondial's original R12 York compressor system to R134a many years ago (with Esther oil), and the current SD-508 was an R12 NOS unit I am running with Sanden SP-20 oil in a R134a system. No issues whatsoever re the use of the compressor.

 

Is it correct you have to change the hoses under the car if u change the system to 134a ?

 

No, I don't think so. I didn't... you would have to change all other hoses too if that was the case.

 

Nah, no need to change any hoses.

 

Look into DURACOOL- if it can keep my Countach cold it can keep Any car cold

 

If the system is not open now there is no reason to open it. The dryer has not been exposed to moisture and therefore should be fine. You can make a case for opening an old system when you can easily change oil, "O" rings, and Schrader valves, but just changing the dryer and refrigerant is not sufficient cause to do so IMO.

If you do open the system I would definitely change the dryer and Schrader valves. I would also change every "O" ring I could access without tearing the car apart (on a Mondial that may not be very many). They are clearly not leaking much now, but "O" rings harden due to age/thermal cycles and the seals/springs in Schrader valves also weaken due to age. IMO not replacing those items when an older system is open would be wasting an opportunity to avoid future problems with the system.

In other words, if the system is currently holding pressure there’s no need to do anything to it unless you want to take the opportunity to engage in some preventative maintenance. Otherwise, just top the system up with R12 and enjoy (assuming the compressor turns out to be working okay). If you do open the system use that as an opportunity to perform as much preventative maintenance as possible, in hopes that will keep you from having to open the system again any time soon.

As to oil, it is not uncommon to see systems with too much oil in them because everyone who opens it feels like they ought to add some. At the least this significantly reduces the effectiveness of the system. At the worst it can hydrolock the compressor. If you don't see any evidence of oil leaks and you're reasonably certain that the system has not been opened/tampered with in the past, the safest course is probably to avoid adding any oil. If you're concerned about the inevitable oil loss from connecting and disconnecting the manifold gauges, adding ~1/2 oz of the original type oil (presumably mineral oil) would be fine, but do not mix types of oil.

 

Good advice above.

Not 100% sure but I would expect a car of this age would use all flare fittings and would not have O rings on the joints. No need to open up the system without good reason.

Older A/C systems used "proper" pipework which lasts. Modern cars use quick-assembly systems which leak after a couple of years.

 

Thanks Ken for posting this.

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I used to be interested in Freeze12 which no longer manufacturers their R12 replacement. That one was not a propane based substitute. Do you know about this one?

I still have 3 cars with R12 based systems all of which would not do well with a R134a conversion which also soon will be hard & expensive to find. So when my 24 cans of R12 run out I'd like to think about a replacement such as this. Perhaps a big canister of it too!

 

If u have got this far, put a belt on the comp and give it a run as you have not lost the gas . Any oil or gas u lost over your arm is such a small %age it is not worth bothering about. In regard to the drier if you do not notice any chilling over it then leave it alone. It should be cool on the inlet and outlet, if the inlet is cool but the outlet is cooler then it is getting dirty, so the liquid F12 is expanding over it and you get the chilled effect when you should not. You would also get a higher discharge pressure.
Re the 134 i think the modification is to fit hoses with special non leak liners- the original hoses are too porous for 134-my dealer offered to convert mine but i stayed with the original as it was an expensive mod

 

Over here any big truck/hydraulics service shop can make up new AC hoses custom sized even reusing your original fitting if that's a requirement. The newer stuff is better and not as bulky. It's not terribly expensive either. I did some last year.

 

Several months ago there was a similar article on AC systems right here on FC and the following link was posted about how two "good old boys" charged an early 80's F100 p/u with R152A also known as computer duster spray. It is funny but if you watch it to the end it actually works. I don't subscribe to it but it is fun to watch.

https://www.youtube.com/watch?v=dl4qOySVru0

 

The proper hose for R134 is called "barrier" hose. Needed to keep the smaller molecules from saturating and leaking out which it will do in your older hoses. If you decide not to replace the hoses you may find topping off more than usual.


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