Expansion Valve - did search, is my 1982 same as 1983? Should I replace? - PeachParts Mercedes-Benz Forum

willrev · #1 08-03-2006, 08:29 AM

Did the search and found post about expansion valve on AC and it said on a 1983 300SD it was located under the driver's knee panel above accelerator.
My 300SD is a 1982. Is the location the same?
Post said that you would need crow feet wrenches 17, 19, 22, 24mm.

I am guessing you will need new o rings for the valve?

I need a new compressor and was going to crack my own system, put on the compressor, expansion valve - take to my dealer and let him put on the drier right before he charges it with R134 for me.

My air is ice cold right now, but my compressor is locking up when the car is idling or moving slowly. It locks up intermittantly and I cut it off and restart it and it is ok, as long as I am moving.

New compressor from my local parts guy is $275. This is not rebuilt, but a new one.

Should I go ahead and do expansion valve while I am at it?
And where should I vent the freon? I know I am supposed to recycle, but I don't have the equipment and can save some $$$ by doing the labor on the compressor and expansion vavle on my own.

#2 08-03-2006, 09:14 AM

Does your system currently have R-134a, or are you converting it from R-12?

Bring it to the shop to have the old coolant evacuated before you start.

Were you planning on flushing the system before installing the new compressor?

JimmyL · #3 08-03-2006, 09:31 AM

In order for the compressor warranty to be valid, it is usually required to replace the exp valve.

Hit Man X · #4 08-03-2006, 11:19 AM

Yes replace it. Just like the switches on the dryer and all o-rings. I think I paid about $4.60 for each o-ring pack for my cars. These are the new Nylog units also.

Also, flush the system. The labor on it to pay a shop is minimal and if your compressor is starting to die...

~$300 seems high for a new R4.

jbaj007 · #5 08-03-2006, 11:26 AM

Call the people listed in post #4 for a NEW R4. You'll get a nice surprise compared to the price you're talking:
Notes on AC Compressor Replacement - Turning and adding oil

Hit Man X · #6 08-03-2006, 11:30 AM

Ah yes, that's where I picked up my F150's new comp a while back. I couldn't ever find them again on there.

willrev · #7 08-03-2006, 02:01 PM

To order an R4 Compressor from Techchoice Parts, I need the offset for my 1982 300SD Compressor pully. Do any of you know what that is???

He did not have my car listed but had an R4 single groove pully compressor for $190.

He said to measure from the middle of the groove to the back of the compressor to get the offset.

James L · #8 08-03-2006, 03:23 PM

ackits.com for NEW R4 with everything you need; pully, correct clutch gap and correct size sealing washers.

Rebuilds; (ok if using R12 but if using higher pressure R134A, I would go new) my Apco air lasted about 1 1/2 years with 134A.

Rebuilds; Behr, Apco Air, Murray, 4-Seasons

also beware that generic GM R4s may not have the correct size/orientation of the metric mounting thread holes, elec spade connector or oil port orientation as the R4 for mercedes.