Re-seal Harrison Radial 4 R4 Air Conditioner Compressor

Hello. I have made a video showing how to re-seal an R4 compressor. It is on an A-body car but I know the LC2 engine also has an R4 compressor on it. I hope this will help someone to repair their compressor economically.

One problem with the units purchased at the auto parts stores is, the rebuild shops are under pressure to do it cheaply and they may use low-cost parts to repair the unit; in particular the shaft seal.

Often the R4 will start making noise and fail mechanically before it needs re-sealing. But on the off-chance you have one which is still tight and only leaking; you can re-seal it with a new double-lip seal and body shell O-rings.

I did fabricate one special tool to press the shell off the compressor. Other than that, the other tools were commonly available.

I mention in the video, the seller who I purchased the parts from. I have no relation to him. I want to provide references so that if you want to recreate the results I got, you have a starting point in your search for parts. I hope this does not make people consider my video to be inappropriate.

I plan to do a video on the V5 compressor also.

Sincerely,
David

 

HyperV6

Member
Great video with lots of tips. I learned a ton. I need to change the front compressor seal on my R4. I was hoping to keep the compressor on the car. Is it possible or do I need to remove the compressor?

Thanks, Craig
 
Hi Craig. Glad you liked the video! Yes it's definitely possible to change the shaft seal with the compressor on the car. You only need to remove the Freon, and then pull off the clutch hub. No need to take the belt off or remove the pulley.
 

HyperV6

Member
It may be easier for a first timer to remove the compressor and then try the repair. Where did you get the clutch hub puller and install tool? Where did you get the plastic thimble that protected the compressor shaft / key way from damaging the new seal? My front seal was leaking and I didn't use my ac for several years since I didn't want all the oil on my original hood liner. I believe now the freon charge is gone. I'd prefer to fix the original compressor and recharge with R12. I have a new front seal kit from AC Delco and have R12. Any suggestions on how much mineral oil I need to add to the system? I'm thinking 1.5 oz.? Thanks for any info.

Craig
 
It may be easier for a first timer to remove the compressor and then try the repair. Where did you get the clutch hub puller and install tool? Where did you get the plastic thimble that protected the compressor shaft / key way from damaging the new seal? My front seal was leaking and I didn't use my ac for several years since I didn't want all the oil on my original hood liner. I believe now the freon charge is gone. I'd prefer to fix the original compressor and recharge with R12. I have a new front seal kit from AC Delco and have R12. Any suggestions on how much mineral oil I need to add to the system? I'm thinking 1.5 oz.? Thanks for any info.

Craig
Hi Craig.

The clutch hub puller and installer is a kit I bought at Advance Auto Parts. I don't remember the name brand they had when I purchased it, but they currently stock the Astro brand AST7886 puller. They usually "rent" these tools, too.

In the past, the shaft seal kits have included the plastic thimble tool. I bought those shaft seals from a local parts store. They weren't the "good" double-lip seal but they did include the thimble. The double lip seals don't include the thimble. There is a metal tool available from the same place where the seal kits came from.

I would be very certain to get the double-lip seal even if you have to buy another one and abandon the new one you have now. The double lip is supposed to mitigate the oil slinging and seepage while stopped.

The set of body O-rings is Santech MT2119
The shaft seal, oil wick, and o-ring is Santech SK-741N
The seal protector thimble is Mastercool 90484

If the system has been slinging oil and has lost its Freon charge, you may want to change the dryer before you charge it. A lot of the oil resides in the dryer, absorbed into the desiccant bead bag. I would pour out what is in the dryer and measure it. There will still be about 2 ounces absorbed into the desiccant that will not come out. Then pour into the dryer about 2 ounces more than what came out, plus whatever you think may have been lost from the compressor.

If there's still some pressure in the system and you don't believe that air and moisture have gone into the dryer, you may want to just add an extra ounce or two to the compressor and let 'er rip!

Sincerely,
David
 

HyperV6

Member
David, thanks for all the information. I want to get this fixed and want to reuse my original compressor since it only has 35,000 miles on it.

Craig
 
I'm glad you found it useful. I'm sure that compressor will last quite a long time once it is fully charged and has good oil in it.
 

HyperV6

Member
My ac system still has pressure in it. I think I'm just going to replace the seal and add more oil. Anyway to add oil when I have the shaft seal out to the compressor? I'd prefer not to disturb any other seals if possible since I see no signs of them leaking. I guess If I added oil to the compressor most would go into the dryer after running some? Any suggestions would be appreciated.

Thanks, Craig
 
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