New R-4 A/C compressor came apart.
 

1985 300SD. An a/c tech. replaced my old compressor with a new (not re-manufactured) Delphi unit. Flushed system and replaced rec/drier complete with new pressure and temp. switches. Charged with R-12, and correct oil. The vent temp. would not go below 60 deg. F. On Sunday it quit blowing cold air, even though the compressor was engaged and the aux. fan was working.

On Monday, I was on the interstate and turned on the a/c. It cooled down from 85 to 60 in the vent. After about 20 minutes, I heard a POP and saw a puff of vapor in the rear-view mirror.

I pulled over, looked at the compressor and noticed that the outside canister had separated from the backside of the compressor. This revealed about an inch of shiny stainless steel and a large o-ring where the canister slid forward. This was caused by high pressure (I guess). Is there a switch or thermostat that could be bad? I believe that the temp. and pressure switches on the rec/drier only control the aux. fan. Is there something else that I should replace when the job is done next time?

Thanks,

did you replace the drier and expansion valve?
***Edit*** I just re read that you did replace the drier...

Did your tech put all the bolts back in? And torque them down properly?

On the W123 application there's a bolt that runs the length of the body of the compressor and connects to a bracket for the hoses. I thought it was just a mounting bolt, but I think I've read where more than one compressor has popped open. It seems to me that bolt may be structural for the R4.

Visible in the pic in post 9 in this thread: http://www.peachparts.com/shopforum/diesel-discussion/281663-installing-compressorworks-r4-into-w123.html

BTW: new compressor should be warranted, but maybe not for R-12 apps. Your call on how much info to give to the retailer.

I did not replace the exp. valve, but will next time. All of the long bolts are still tight.

Thanks,

Where did he get the compressor from Bruce?

Sorry to hear that :( Do you happen to have any pictures?

I have a hi/lo pressure switch on mine. Does the factory setup have a hi pressure switch?

I GUARANTEE that all bolts are NOT tight if the compressor separated...

there are THREE mounting bolts that go from the rear of the compressor to the mount, and there is ONE bolt that goes from the front of the compressor ALL THE WAY THROUGH the compressor to the back...
odds are VERY good that the 4th bolt is still in your original compressor... and you have an empty hole in your new one...

I agree, and would add it's possible he's also missing a spacer on one of the long mounting bolts.

The three mounting bolts may have been snugged into the brackets, but if the rear portion of the compressor "burped" backwards, then I think something is missing. The parts shouldn't have the range of motion to move a 1/2 inch backwards.

actually, what happens is the front of the compressor gets ripped out of the rear section, and the large o-ring that's surrounding the compressor body pops out. makes the thing look like the rear popped out, but if you look from underneath, you will see the rear section is snuggly mounted, and the lower front is tilted towards the radiator.
VERY common problem (it's happened to me twice... Thanks Thayer) ya gots to get that 4th bolt in.

The pic is here in post 51. http://www.peachparts.com/shopforum/diesel-discussion/280510-dissembling-r4-compressor-4.html

If I'm interpreting it correctly, you can see the herniated O-ring (I'm going to copyright that) popping out on the left side of the image, about half way up. Other pics - and discussion - are here: http://www.peachparts.com/shopforum/diesel-discussion/282703-holy-thayers-new-compressor-just-blew-seal-4.htmlhttp://www.peachparts.com/shopforum/diesel-discussion/282703-holy-thayers-new-compressor-just-blew-seal-4.html

Jim,
The compressor came from acpartsguys.com.

To rephrase, the compressor did not come apart. The shield or canister that surrounds the compressor separated with a loud pop and slid forward. The compressor is still mounted securely and the pulley is still aligned perfectly with the drive pulley.

Wow :eek:

I'm guessing that the 4 mounting bolts tighten against the front of the "band" while the angled "tang" provides assistance?

Seems like it would just blow towards the rear though...

...
ok, now i'm irked...
if it's not the bolt that holds the cover on, WTF is supposed to prevent this from happening? possibly large washers holding the skirt in place on each end?

I'm a bit confused as well. I don't see how the missing bolt causes this issue. Maybe the case gets distorted from only having 3 bolts and causes the o ring to fail?