R4 AC Compressor for W123 - PeachParts Mercedes-Benz Forum

vwnate1 · #1 01-15-2017, 01:44 PM

I'm looking at a new # 1521764 Delco compressor for my '82 240D .

It says this one is Metric and will need a Metric bolt kit .

Is this correct ? I wonder because it looks slightly different than the old original R4 compressor that still works O.K. but weeps at the shaft's ceramic seal and @ 360,000 + miles I figure it's smart to replace it whilst doing a light engine overhaul and tranny rebuild etc., etc.

FWIW, this R4 is in the parts catalog for the 1984 W123, 1988 Cadillac Fleetwood and lots of other post Metric change GM vehicles, prolly why it's so darn cheap to buy .

I just want to try it and not buy it if it won't fit .

TIA,

my123ca · #2 01-16-2017, 01:20 AM

I believe thats what they call R4 lite. The only bolt that you will need is the one for the manifold. Only problem is where the terminals for the coil will be oriented. You dont want it on the bottom.

leathermang · #3 01-16-2017, 09:55 AM

I am NOT sure but you might want to investigate , since it is listed for a different car, whether it ( the face ) needs to be ' clocked ' differently for mounting on your car... perhaps with respect to the position of the front seal oil lubrication situation. ????

vwnate1 · #4 01-17-2017, 04:52 PM

Thanx guys ! .

I don't see why I wouldn't want the clutch coil's plug on the bottom as that's where they are from new.....

(looks kinda strange to me but works fine)

Getting the Metric manifold bolt shoudn't be any problem, I'll just go to my favorite Junk Yard and grab one .

BillGrissom · #5 01-17-2017, 09:31 PM

Quote:

Originally Posted by vwnate1

Thanx guys ! .
Getting the Metric manifold bolt shoudn't be any problem, I'll just go to my favorite Junk Yard and grab one .

Even simpler, I got a bolt at Ace Hardware. I recall several trials on one of my cars - stud & nut, allen-head bolt, regular hex head bolt. Stud is best to not strip the threads, but recall not enough room for a wrench. Forgot why the hex didn't work, but a regular hex-head worked best.

One thing to look for is the "GM Pad" sealing surface. There are several threads w/ photos of the variances. I prefer a compressor w/ O-ring grooves, since O-rings are simple and work well (use HBNR or Viton). Many have bores for "seal washers", which come in various thicknesses. M-B compressors used yellow and green (suction & discharge, resp.), but there are many other compressors in the supply chain.

vwnate1 · #6 01-18-2017, 10:19 AM

Thanx Bill ! .

The catalog showed both types of sealing surfaces for the same part # and I was wondering about just that .

I like the green O-Rings as I've (so far) never had one fail .

I think I'll go pick this compressor up to - day, hopefully it'll use the O-Ring typ of seals .

funola · #7 01-18-2017, 10:48 AM

I think only the old "heavy" R4's with the big clutch coil uses o-ring seals on the manifold. The R4 "lites" use the stepped washer seals which are hard to get right. I have read some of the new R4's "lites" are not very good quality compared to the old "heavy" R4's. If your old R4 has a leaky ceramic seal, it can be replaced with a more modern double lip seal, which has a much lower leak rate. While you're at it replace the other o-rings and you're compressor will be good as new.

vwnate1 · #8 01-18-2017, 10:53 AM

Oh, boy ~

Now you tell me .

I'll go give it a look and see what's what .

Even with close to 400,000 miles you think the current R4 compressor is worth re sealing ? .

funola · #9 01-18-2017, 11:02 AM

Quote:

Originally Posted by vwnate1

Oh, boy ~

Now you tell me .

I'll go give it a look and see what's what .

Even with close to 400,000 miles you think the current R4 compressor is worth re sealing ? .

You said your current R4 is still putting out cold air, that means it is working fine. If the bearings feels smooth and not grinding the compressor is basically sound. 35 year old o-rings and seals tend to get compressed and not seal well and should be replaced. I resealed a R4 last year and posted pics. It is not difficult (unless you listen to Leathermang) if you have the DIY tool to press the shell off/on.

vwnate1 · #10 01-18-2017, 11:06 AM

I don't see any weeping around the shell.....

Hmm .

Food for thought here .

funola · #11 01-18-2017, 11:09 AM

Quote:

Originally Posted by vwnate1

I don't see any weeping around the shell.....

Hmm .

Food for thought here .

No weeping now does not mean it will not weep soon. When I had mine apart, the o-rings were flat instead of round. It would be foolish to not replace them when you replace the ceramic seal.

leathermang · #12 01-18-2017, 08:53 PM

Quote:

Originally Posted by funola

It is not difficult (unless you listen to Leathermang) if you have the DIY tool to press the shell off/on.

How about expanding on that ? Be specific... show that is not an ad hominem personal attack.

funola · #13 01-18-2017, 11:38 PM

Quote:

Originally Posted by leathermang

How about expanding on that ? Be specific... show that is not an ad hominem personal attack.

dissembling R4 compressor

vwnate1 · #14 01-19-2017, 12:53 PM

A thought here :

I'm a Journeyman Mechanic as are many here and I have learned that people tend to grab on to whatever works for them, often to the exclusion if willingness to learn or even look at a different way or idea/concept .

So ~ what might appear to be an attack may in fact just be ' this works for me make no mistake ' .

Me, I love to learn new ways ~ it took me a long time to even try the 3 second initial breaking regimen for new or rebuilt/overhauled engines because it just didn't seem possible/was scary sounding/was the exact reverse of how I'd been doing it since the 1960's but in time I decided to give it a try on a $25 used car I'd bought with a ruined engine and Lo ! IT WORKS, so I learned a new thing .

Point being : I learn things here every time I come, even when there are opposing viewpoints .

As far as the R4 compressor here's the secret detail I left out before :

It was a new one on a 1988 Cadillac Fleetwood Coupe and I could have gotten it for $40, I schlepped way oout to the sticks trying to beat the rain but discovered when I open the trunk that I'd neglected to put my tools back in the car after cleaning up/out the trunk last Monday so I didn't get it and now it's soaking wet because the Caddy's hood was off and we're getting serious rain .

Oh well .

I'd checked the catalog and the P/N for '88 Caddy Fleetwood and '84 W123 is the same .

Maybe I'll just look into this improved compressor shaft seal instead .

leathermang · #15 01-19-2017, 12:54 PM

Quote:

Originally Posted by funola

dissembling R4 compressor

THAT is evidence that sometimes the clocking needs to be checked.. which is what I was saying... .and it was a thread started by YOU..