New R-4 A/C compressor came apart. - Page 2 - PeachParts Mercedes-Benz Forum

cbjukraine · #16 05-30-2012, 09:02 PM

Bruce, you're not alone on this. The exact same thing happened to me with an R4 compressor from ********az. However, I wasn't driving down the road. Mine blew while I was charging the system in my garage. I bought the Bosch (China) from them. Sent it back for a refund.

The thing I don't understand is there is supposed to be a high-pressure release valve on the back of the compressor. If the problem had been too high pressures, I would think the blow-out valve would give way and keep the entire compressor from self-destructing.

tangofox007 · #17 05-30-2012, 10:19 PM

Quote:

Originally Posted by Bruce Bonds

I believe that the temp. and pressure switches on the rec/drier only control the aux. fan.

The temp switch operates the fan; the low pressure switch prevents the compressor clutch from engaging when the refrigerant pressure is extremely low.

rrgrassi · #18 05-31-2012, 12:02 PM

I used a High/Low pressure switch on my system in 2007. My system is still running with no issues. I am still using freeze-12. The compressor is a Hodyon/Hancock Industries bought brand new, not reman, through NAPA. I did replace the drier and expansion valve and flushed the entire system. I used BG Frigiquiet oil as well.

I did come across the Sanden 508 mounting bracket so that when the current R4 dies, I can use the Sanden.

Air&Road · #19 05-31-2012, 12:14 PM

Quote:

Originally Posted by Bruce Bonds

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,

I FULLY expect that the system was not adequately flushed. This is not to imply that you did not make a gallant effort to flush it properly, it's just that often it's nearly impossible.

When you put in the next compressor, find a suction side filter and install in the low line leading to the compressor. It's the only practical cure in this case.

buch32 · #20 06-21-2012, 03:38 PM

Quote:

Originally Posted by Bruce Bonds

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,

1980 300SD--Mine blew about 10 second after I shut of the engine....It had worked very good on an 80 mile trip. After cool down checked the reman compressor and discovered that the 4 5/8" bolts were all loose or finger tight. Canister did not separate as you described but when pressure was applied to the system it vented around the back side of it.
Carefully following recommended procedures I am currently on my 2nd NEW OLD STOCK compressor and supporting components with poor results. Low side =80 high=150; A/temp=84;H/43%; center vent=65* In-line filter shows rapid flow of 134a. Stil troubleshooting in spare time