Used R4 compressor - PeachParts Mercedes-Benz Forum

James L · #1 05-05-2010, 12:22 AM

I found a Delphi-Delco Harrison R4 off a 1983 W126 in the local salvage yard. Lines had OE R12 fittings. Freon was still holding when removed (heard a hiss). Also got the manifold hoses that connects to it.

Rinsed/flushed with mineral oil. Turns real easy and smooth by hand, no hard or rough feeling spots. I covered the ports with finger and can feel a suck on the suction and a pop on the discharge port when I turn clutch by hand. No metal contamination comming out, clutch clicks and moves when 12 volts applied.

Does a good R4 turn easy by hand? If so, should I give it a try and swap it out? Also anyone know who could do a fabricate job on my a/c compressor manifold hose to put a filter/connection and redo the rubber parts? If so where do I put it on the suction side or discharge?

There was a thread on this salvage R4 issue a few months back but I searched and could not find it.

Thanks for the help.

dstorey · #2 05-05-2010, 01:18 AM

Assuming there was enough gas discharged that it was not just a warm day, the system was still sealed and thus no moisture got in. good practice involves new seals, expansion valve and receiver dryer. If you can get reclaimed R 12 you are better of as the seals in the compressor will not stand up to the oils used with 134a, The GM compressor is good if you carefully measure the oil charge. Good luck

#3 05-05-2010, 08:02 AM

Your course of action is determined more so by the compressor you took off than the compressor you are putting on.

Why are you replacing the compressor? Was the old one just leaking? Was it locked up? Was it not compressing?

biodieselkid · #4 05-05-2010, 08:11 AM

Is there a way to replace just the clutch. The electrical connector, on the clutch, failed. I know this to be the fail point. Double checked it. Is there a way to replace this or just the clutch without removing the compressor. Thanks, James

James L · #5 05-05-2010, 09:34 AM

Larry, my compressor clutch/pulley is making noise when on, the clutch/pulley is kind of wobbly when looking down like the bearing is going. Compression on the high side will not get over 150 psi (R12) even at full charge, can see freon moving thru sight glass.

There is a leak that I can not find; dye is in system but can not see any, also my sniffer does not detect any. I am assuming the leak is inside the R4 at the one of the clutch bearing/seals. When I remove the R4 I may take apart to see.

Seems like new R4s are harder to turn by hand, compressor works web site says have to use a spanner wrench, will not tun by hand. (good read);

STEP 2. SYSTEM FLUSH
It is CRITICAL that the system be flushed (cleaned) prior to installation of a new replacement compressor. The evaporator, refrigerant lines, and condenser (if applicable) must be flushed separately. Closed loop refrigerant flushing is highly recommended. Flushing with an approved flush agent is acceptable provided that the agent is used in the liquid state and the components are air dried using filtered/dried compressed shop air. Oil based flush is not recommended.
STEP 3. CONDENSER REPLACEMENT
Late model vehicles are being designed with compact, high performance parallel flow condensers which have very small
refrigerant passages. These small passages make it impossible for these condensers to be properly flushed. A good
example of this is the condenser on the 2002 – 2004 Honda C‐RV. The condenser should be inspected at the inlet port
(compressor discharge line) for signs of debris from a failed compressor. If any debris is present, it is highly
recommended that the condenser be changed.
STEP 4. ADDITION OF LUBRICANT
Replacement compressors are typically shipped dry (no oil). Use the type and
quantity of oil specified by the vehicle manufacturer or the CompressorWorks “AC
SYSTEMS TECHNICAL SPECIFICATION GUIDE”. PAG oils are used with R‐134a
refrigerant and mineral oil with R‐12 refrigerant. Add 2.0 – 3.0 ounces of the
specified oil to the compressor through the crankcase drain port or the suction port as noted by the ADD OIL decal. Rotate the compressor, using a spanner wrench or clutch hub turning tool, at least ten (10) revolutions to distribute oil. Note: Some compressors, for example GM H‐6 or Ford FS‐10, may not rotate by hand due to internal component preloading. For an orifice tube system, add the balance of the oil charge to the accumulator dehydrator (AD). For a TXV system, add 1.0 ounces to
the receiver dryer (RD) and the balance to the evaporator.
STEP 5. SYSTEM ASSEMBLY
Install the new replacement compressor, AD or RD, orifice tube or TXV, muffler or filter, and condenser (if required). Evacuate the system to at least 99.4 kPa (29.5 in‐Hg) of vacuum for forty‐five (45) minutes to ensure all moisture and residual flushing agents are boiled from the system. Observe the low pressure gauge for five (5) minutes to ensure the system holds vacuum. If vacuum is not held, leak test the system, repair leak point, and evacuate system again.
STEP 6. SYSTEM REFRIGERANT CHARGING
Recharge the system using the refrigerant type and quantity specified by the vehicle manufacturer or the CompressorWorks “AC SYSTEMS TECHNICAL SPECIFICATION GUIDE”. Use an accurate scale or metering device to ensure the proper refrigerant charge level. Crankcase Drain Port
Clutch Hub Turning Tool 350104 Rev. 4.09
Note: Improper refrigerant charge is a major cause of premature compressor failure and poor system performance.
Use a refrigerant leak detector to check the system for leaks. If a leak is found, remove refrigerant charge from the
system, repair leak point, evacuate, recharge, and leak test.
STEP 7. PERFORMANCE TEST & DIAGNOSTIC PROCEDURE
1. Start engine and allow it to reach NORMAL OPERATING TEMPERATURE. Set A/C system to MAX COOLING (RECIRC),HIGH BLOWER SPEED, all DOORS OPEN, and ENGINE SPEED @ 1500 RPM. Allow system to stabilize for 10 ‐ 12
minutes.
2. Visually check for loose mountings, rubber hoses or metal pipes that are contacting other vehicle parts. Theseconditions may produce a noise problem. Check all connections for possible leakage.
3. Monitor pressure gauges for proper operation. Excessive high pressure readings on high/low side pressure gages
may indicate one of the following problems:
a. Refrigerant overcharge.
b. Improper engine cooling system performance such as restricted radiator air flow, inoperable electric fans, and/or faulty fan clutch.
c. Blocked or restricted AC component (condenser, evaporator, orifice tube or thermal expansion valve (TXV))
passages resulting from debris caused by the previous compressor failure.
4. Monitor center dash vent temperatures for proper cooling. An average temperature difference between ambient
(86 °F / 30 °C outside temperature) and vent temperature of 20 ‐ 30 °F (11 ‐ 17 °C) is acceptable at about 1500
engine RPM but is dependent on ambient conditions. If poor performance is observed, please check the following:
a. Refrigerant undercharge. Can also be observed as frequent compressor cycling (on/off). b. Low / no power to compressor clutch. Can be observed as clutch slippage or non‐engagement.
c. Improper air source selection. Set A/C system to re‐circulating inside air (RECIRC).
5. Check entire system using an electronic leak detector. If dye has been added to the system, it is most important to check the system with an electronic leak detector. The indication of dye does not necessarily mean a leak is present (particularly at o‐ring joints and shaft seal locations). Always use a leak detector to verify leak indications by dye.
6. If excessive compressor noise is encountered, please check or verify the following:
a. Lubricant (oil) and refrigerant quantity. Noise may be due to an undercharged or overcharge of lubricant or refrigerant. Verify that the correct type and quantity of oil and refrigerant have been used.
b. Condenser restriction. Compressor noise may be caused by high discharge pressure created from a plugged
condenser.
c. Contaminated system. Debris from a previous compressor failure can destroy the bearings in the
replacement compressor resulting in excessive noise.
d. Improper flushing agent. Residual flush can cause severe compressor damage by a chemical reaction which
degrades lubricant performance.
7. Change A/C system settings to MAX COOLING (RECIRC), MEDIUM BLOWER SPEED (or LOW), DOORS CLOSED, and
ENGINE SPEED @ 1500 RPM to insure that the system controls allow proper cycling of the compressor by reduced
system performance demand. This does not apply to variable displacement compressors.

bio, not alot of room to take clutch off on car. There is also some special R4 service tools that may be needed. And it is not just the clutch but seals and bearings that go with the clutch when removed (may lose freon). Did the elec connection break? if not try some CRC electrical cleaner.

James L · #6 05-05-2010, 09:50 AM

Another good read from the compressor works web site. They claim there R4s are new and are built to last. I may call tech support and verify the built to last processes they claim on the web site. (autozone sells these for $238 new).

http://www.compressorworks.com/default.aspx?page=Rfour

"Best Practices
Have the system refrigerant recovered by a certified repair facility.
Always replace the orifice tube, accumulator, and receiver/drier/filter when replacing the compressor.
Ensure that the correct amount and type of A/C lubricant is used. OE suppliers recommend the use of PAG lubricants.
Add approximately 25-30% of the entire system lubrication charge to the compressor. For example, a GM system requiring 8 ounces of PAG lubricant will have approximately 2.5 to 3 ounces of lubricant added to the compressor. Whenever possible, add the lubricant in to the suction port of the compressor as opposed to the discharge port. The remaining 5.5 to 6 ounces of lubricant should be added to the accumulator (or to the evaporator if the system has a thermal expansion valve). One ounce may be added to the receiver/drier/filter if desired. The lubrication specifications are normally expressed as the lubrication requirements for the entire system. If the entire system is not flushed, it is almost impossible to determine the correct lubrication refill requirements.
Turn the compressor shaft a minimum of 12 turns as part of the installation process. This will aid in the distribution of lubricant throughout the compressor. Please note that many compressors are very difficult to turn by hand. When turning the GM R4, HR6, HD6, & HT6 compressors, a spanner wrench should be used.
If the system is heavily contaminated, it may be necessary to replace additional components to ensure that the compressor will function as desired.
If 'Black Death' symptoms are present (a dark gray or black oil/oily residue), it may be necessary to replace the entire A/C system. Failure to do this will result in repeated compressor failures.
Flush the entire system with an approved flush chemical. Some chemicals may cause serious harm to A/C components. Brake Clean, Acetone, Mineral Spirits, and Gasoline are examples of chemicals that should never be used to flush an A/C system.
If adding dye or another leak detection chemical to the system, ensure that the correct type is used. No more than 1/4 ounce of leak detection dye is necessary. If using refrigerant with dye, the additional dyes are necessary. Excessive amounts of dye may cause a break down of system lubricants.
Shaft seal leakage or seepage is normal for the first 8-10 hours of compressor operation.
Ensure that the air gap (clutch gap) is within specifications. When testing the gap, a brass or plastic feeler gauge is suggested as metal gauges often give erroneous readings.
Always 'burnish' the clutch as part of any new compressor or clutch installation. This can be performed by using the low pressure switch to manually cycle the compressor on and off 30-40 cycles. This procedure should be performed only under normal engine operating temperatures and when the engine is at idle speed. This procedure will aid in reducing or eliminating clutch slippage and possible clutch failure.
When recharging, ensure that the correct refrigerant type is being used for the system being serviced. If retro fitting (migrating from R12 to HCFC134a) is being done as part of the repair, be sure to follow the specific manufacturer's instructions for this procedure.
Lubricate all O-Rings with mineral grade lubricant.
Evacuate (pulling a vacuum) for at least 30 minutes. Failure to properly evacuate the system may result in a failed compressor or result in a system that fails to cool properly.
Recharge to OE specifications. If possible, have the system service by a certified and licensed technician. It is almost impossible to properly charge a system using pressure as the only measurement.
Test the system for proper performance after the repair to proactively diagnose possible problem areas.
Test for leaks after repairs have been completed.
Replace the fan clutch (if applicable) if the vehicle has more than 50,000 miles or if the system displays excessively high high side pressures.
Late model HCFC134a systems may require the replacement of the condenser as part of the compressor or A/C system repair. The design features of these condensers prohibit the ability to adequately flush (clean) the condenser. Failure to replace the condenser may cause compressor failure or inadequate cooling performance".

Interesting on the "burnishing the clutch"; cycle 30-40 times. Anybody doing this?

James L · #7 05-05-2010, 11:46 AM

I am going to swap out the R4, pull a vac, see if it holds, then test charge with a small amount of R22/dye to pressure test, sniff again and see if it will get a good high side psi. If all is good I will evac and charge with R12.

All I have to loose is time and sore back..LOL