Does anyone have a chassis service manual or similar, that gives details of the rebuild process for the R4 a/c compressor? The GM shop manual for my 80 is very light on rebuilding procedure/use of special tools etc.

I'm just curious at the moment, and just trying to soak up as much info as I can.
I know from reading around that people are going to say "don't rebuild an R4 compressor" but I haven't really worked out why people say that yet.. I don't fancy shipping a new one to the UK, as I'll get shafted big time for shipping and duty.

Essentially a shop manual for any car that used that compressor will do, i guess. There seems to be next to no rebuild info on the net, but it must have been published. Can anyone kindly scan some pages for me?!

Cheers folks

 

I hate to say it, but those R4 units are a real POS, and so can NOT be rebuilt other than with a dedicated shop...you wasting you time barking up rong tree...sorry, but it's true....

you far better off getting a later Sanden/Sankyo? San something compressor, and mounts and put it in there, to finally kiss that POS goodby.....I would NEVER buy another one, not new Gm, not used, not rebuilt...too much bad experiences with them....the pistons use plastic rings in there, nuff said....case closed....

GENE

 

You may want to consider swaping it out for a Standen compressor. The GM rotary compressors sling a lot of oil and are not the best to begin with.

 

Hey guys, cheers for the responses.
As I'm in the UK, I don't get that many chances to even use the AC. But it was good while it worked, and I'd like to get it going again one day. It's at the bottom of a big list of things at the moment, and as I said, I'm only really just gathering info at the moment. The important thing is that the compressor worked fine until one of the connectors on the clutch broke so at least one of the jobs is to pull the clutch off and repair that.

It's going to need recharging when I fix the clutch, so I wanted to know what kind of a job it is to put new R134 compatible seals in the compressor, hence the question about rebuild info.
I can see the benefit of putting an aftermarket compressor in, or swapping to an A6 or similar, BUT it'll cost a lot to ship a heavy old compressor over here.

Feel free to object but I'd rather TRY rebuilding it to make it compatible with a fresh charge than shell out several hundred quid for a new unit that will mainly be used for one month every year.
If it subsequently dies, lesson learnt, but for the cost of a few seals and bearings I'm willing to try.

For a lot of people, myself included, part of owning an old corvette is the "fun" of refurbing the old parts, and the grey hairs that induces

Gene, I can see you're obviously not a fan of these things (!) and you've clearly got a lot more experience in them than me (this is the first ac car I've ever owned) but...... WHY can they not be rebuilt??? I'm after specific physical reasons. I have access to some top class workshop facilities, can happily make my own tooling if necessary and work with people who have hundreds of years worth of machining experience between them. BUT if someone can actually tell me the exact reasons why they can't be rebuilt I wwould admit defeat
Don't get me wrong, I'm not trying to be aggravating- I just want some more facts and evidence with some engineering basis..... And I'm a stubborn S.O.B!

 

I can fully understand your reasons for wanting to rebuild your R4 compressor due to cost. Once you repair the broken connector it should still work so just run it until it fails.
After it fails you could do exploratory surgery on it. If it's repairable, great, if not you could adapt any automotive A/C compressor that is commonly available to you in the UK.

One of the connector broke of my original R4 compressor too. I replaced the clutch and ran it up until I swapped engines. At that time I replaced the original R4 with a remanufactured one because the original was getting noisy. The reman. unit is noiser than the original.
However, it's still working but when it fails I will probably install a different compressor such as the Sanden.

If you tear into it, please post pictures of the internals.

Mike

 

Mike
You understand mate!
You've essentially re-phrased my exact thoughts on the matter. I will definitely get some pics together if/when I take the job on, but it won't be for a long time yet - I'm expecting it to take a while to get enough info together.

I'm still keen to hear back on the potential pitfalls though.....

 

Get yourself a genuine GM shop manual -- specific to the model year -- for your car. My '79 manual shows detailed R4 rebuild procedures. Several pages' worth...

 

Um, my 76 manual has the rebuild procedure. 27 pages long. I would definately not try it.

 

Page...

That's the thing, I DO have the gen-u-wine GM manual for the 80 but it has no actual rebuild info on the compressor, believe it or not! Only recharging procedure, disassembly of pipework etc.... There's a list of special tools with pics, but no info on how to use them.

I knew it! Everyone else has this info apart from us poor 80 owners, it must be a conspiracy!

I don't suppose there's any way you could scan the rebuild info from your 79 manual and either post it or email it to me?? I appreciate it's not a five minute job, but I'd be a really very happy chappie if I could see it..

TIA

 

Geez, they're all coming out of the woodwork now- in the time it took me to write that last reply here's someone else!

Seriously, if anyone here feels kindly enough to scan those pages I'd be very grateful. You can appreciate it's a bit of a false economy to buy a whole other-year manual just for the A/C parts of it.

Don... did they have the R4 or A6 compressor back in 76?

 

I was involved in building many an R4 compressor and GM in fact designed them as a throw away type design. Kind of like a Bic lighter.
They are very much a pain to try and rebuild with computer spec matching of parts. Not like the A6 which is quite rebuildable. Good Luck!

 

Fair enough Guppie, I guess the pain involved in rebuilding them depends on how many of those "matched parts" are worn out on mine. Only one way to find out and that's to pull it open.

So the question still remains.. can any of you guys possibly scan some rebuild pages for me???

 

I can probably scan some pages . . . next week. Send me an email to remind me.

In the meantime, check your 1980 manual again. The rebuild procedures are AFTER the tool pix. Seems illogical, but I found the info by turning a few more pages.

BTW: You can reseal one of these -- if that's all the problem is -- they even have an "on-car" procedure.

 

The new ones from GM will last a long time & are lightweight & out of the way.
You can replace the seals. An old outside housing is said to work well for pressing the housing off & replacing the large seals.
Shaft seal replace: http://trotliner.tripod.com/ac.html

If A/C is not needed, would remove all of it.

Replaced mine w/ a custom Sanden type w/ brackets of my own design.

 

Cheers guys,

Ganey - thats great info, thanks. I searched high and low (obviously not high and low enough) for any pages like that link, and came up with zilcho.

Page - I really appreciate that mate, thankyou. Since my last post I've put a message on the UK vette forum and I have a contact there who is going to scan the pages from his 78 manual for me on Monday, but I'll keep you in mind just in case his manual is anything like mine and is lacking the important bits.
By the way, I have my manual here in front of me and it definitely has no rebuild pages for the compressor. I'm pretty sure it's an original book, (came from Ebay so not totally sure, but it looks old enough to not be a reprint) so I'm a bit perplexed. The AC chapter stops at page 1B-25, after the two pages of special tools. Doesn't have any pages removed..... Curious.