Rebuild A/C compressor?
Thread Starter
Burning Brakes
Joined: Feb 2000
Posts: 1,247
Likes: 2
From: Parker, Colorado, USofA
Rebuild A/C compressor?
About a decade ago, the 89's compressor seized and I dropped the coin to convert it to r-134a. This spring, it seized AGAIN.
Earlier in the year, I had a great experience rebuilding a power steering pump on aother car...turned a $500 repair into a $2 one.
I'm kinda wondering if a similar attempt on the vette's compressor wouldn't turn out similarly. A rebuild kit is around $30 online, and I figure that, plus a new accumulator, plus materials and the $15 harbor freight vacuum pump would be the cheapest route.
R-134a hasn't been the BEST conversion, do you think replacing the orifice and going back to r-12 would be worth it? Has a better alternative to 134a shown up in the last ten years or so?
Earlier in the year, I had a great experience rebuilding a power steering pump on aother car...turned a $500 repair into a $2 one.
I'm kinda wondering if a similar attempt on the vette's compressor wouldn't turn out similarly. A rebuild kit is around $30 online, and I figure that, plus a new accumulator, plus materials and the $15 harbor freight vacuum pump would be the cheapest route.
R-134a hasn't been the BEST conversion, do you think replacing the orifice and going back to r-12 would be worth it? Has a better alternative to 134a shown up in the last ten years or so?
Thread Starter
Burning Brakes
Joined: Feb 2000
Posts: 1,247
Likes: 2
From: Parker, Colorado, USofA
What, nothin? A new compressor is a $500 part, if it's $30 worth of bearings and seals, I figured SOMEONE had done it before. (Perhaps it's cuz Daddy was in hydraulics and I watched him rebuild a LOT of stuff)
Slingshot
Joined: Dec 2001
Posts: 3,817
Likes: 24
From: Charlotte NC
Send a PM to Suncr and ask his advice. He'll provide you with sound A/C recommendations.
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
The only replaceable parts are Shaft Seals and Pulley Bearings which are about 50 to 60 Bucks at NAPA. Anything else usually requires new or someone else's rebuild (sometimes no more than a painted case). Assuming you only have a shaft seal leak, then you might be able to fix it. The problem is that those leaks can groove the shaft and nothing will seal that. You will have to take it apart and mic the shaft to see if there's any damage. I don't know of any source for shafts, pistons, internal seals, etc, though you might talk to the guys at www.ackits.com
Slingshot
Joined: Dec 2001
Posts: 3,817
Likes: 24
From: Charlotte NC
Shop around and see what you can find. I found a NOS compressor last summer at a Chevy dealer in Mississippi. He shipped it to me for $165 just to get it off his shelf.
I painted the compressor, applied my old label and installed it.
So, shop around, you never know what you'll find out there hidden in some corner.
I painted the compressor, applied my old label and installed it.
So, shop around, you never know what you'll find out there hidden in some corner.
Thread Starter
Burning Brakes
Joined: Feb 2000
Posts: 1,247
Likes: 2
From: Parker, Colorado, USofA
Le Mans Master
Joined: Feb 2005
Posts: 6,485
Likes: 566
From: Clearwater Florida
..... So ... Why don't you just give it a go and rebuild yours ? ... If you don't succeed you're only out $30 right ? ... If you do win , you can write a report on it ... maybe include some pics ... and possibly inspire another C4 owner to rebuild his own AC system ...............
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Thread Starter
Burning Brakes
Joined: Feb 2000
Posts: 1,247
Likes: 2
From: Parker, Colorado, USofA
That's the plan. The only real issue becomes the gaps in my knowledge, and the gaps in the knowledge of the fella that reads my writeup. 
_I_ know R-134a is, well, less toxic that R-12...but the guy with R-12 in his system might not and condemn the world to no ozone.
But yeah, that's the eventual plan, I'm just laying the groundwork research.
_I_ know R-134a is, well, less toxic that R-12...but the guy with R-12 in his system might not and condemn the world to no ozone.
But yeah, that's the eventual plan, I'm just laying the groundwork research.
Advanced
Joined: Jun 2011
Posts: 57
Likes: 0
From: Charleston SC
Rocket, you can get a brand new Four Seasons compressor from Oreilly's for $169..... put a drier and an orifice tube in too. If your bent on doing it cheap, get a set of gages ($39) and a vac box ($15) from Harbor freight. From the original 2.75lb R12 requirement, R134 is .80% as R-12 meaning you'll only need to put 3 cans in or 2.25lb. Make sure you add about 1-1.5 oz oil to the drier and soak the orifice tube with oil before you install it. After you put the compressor in, add the first two cans of freon before starting the car. You can add the last can with it running, just watch your pressures. You shouldn't exceed 235 on the high side and if the system is running right, 35 on the low side. Hope this helps.
Advanced
Joined: Jun 2011
Posts: 57
Likes: 0
From: Charleston SC
..... So ... Why don't you just give it a go and rebuild yours ? ... If you don't succeed you're only out $30 right ? ... If you do win , you can write a report on it ... maybe include some pics ... and possibly inspire another C4 owner to rebuild his own AC system ...............
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
For the Nippo ('88 to '96) shaft seal you can use this guy's outline. Different model #, same drill: http://www.pelicanparts.com/techarti...so_rebuild.htm
For the Harrison R4 ('84 to '87), they're cheap enough, so I'd just buy new.
Don't know of any internal suppliers for either compressor - shaft seals and gaskets is about all that's available and there are no published tolerances.
For the Harrison R4 ('84 to '87), they're cheap enough, so I'd just buy new.
Don't know of any internal suppliers for either compressor - shaft seals and gaskets is about all that's available and there are no published tolerances.
Thread Starter
Burning Brakes
Joined: Feb 2000
Posts: 1,247
Likes: 2
From: Parker, Colorado, USofA
Converting to R-134a really affected the cooling ability of the system. To make matters worse, I added a big motor, a loose torque converter, and coolers for both of them ahead of the A/C condenser. Above 90 degrees or so, the A/C goes away, I suspect because they're not enough airflow on the cooling stack to reject all the heat. (Turn the A/C off, and everything returns to normal)
Which makes me wonder if going BACK to R-12 wouldn't be a bad idea....unless having better rejection of heat means the cooling stack would be overwhelmed at 85, instead of 90 degrees?
Which makes me wonder if going BACK to R-12 wouldn't be a bad idea....unless having better rejection of heat means the cooling stack would be overwhelmed at 85, instead of 90 degrees?
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
I'm not an a/c engineer or designer, but this much I know - mobile a/c requires average head pressures of about 200 psi to funnel a low pressure liquid that's somewhere around freezing (30 psi for R12; 28 psi for R134) into the Evaporator for vaporization. Idle and Low Speed operation uses fans to maintain the desired pressure and theoretically, it doesn't matter what you put in front of the condenser as long as you have enough air movement to maintain designed pressure/temp. However, the smaller R134 molecule tends to become more compact at higher temps (90 +) meaning that it can exceed design limits for pressure/cooling on those vehicles which use a pressure sensitive switch to control the fan(s); pretty much anything before the LT1 or '92. There isn't anything available on these vehicles to get the fans cranking at lower pressures to maintain system stability at lower speeds, so the only solution is to use less gas which at cooler ambients (below 70) will lead to increase cycling/more wear and tear, and in some cases - because compressor engagement isn't controlled by the ECM - poorer idle control.
Thread Starter
Burning Brakes
Joined: Feb 2000
Posts: 1,247
Likes: 2
From: Parker, Colorado, USofA
Additionally, the car used to have a Z-52 fan in front which I had to remove for clearance reasons. (Hey, find a better place for a real air-oil cooler and air-tranny fluid cooler, I'm all ears. 
) I'm sure the additional airflow it would add would have been helpful.
) I'm sure the additional airflow it would add would have been helpful.
Slingshot
Joined: Dec 2001
Posts: 3,817
Likes: 24
From: Charlotte NC
Converting to R-134a really affected the cooling ability of the system. To make matters worse, I added a big motor, a loose torque converter, and coolers for both of them ahead of the A/C condenser. Above 90 degrees or so, the A/C goes away, I suspect because they're not enough airflow on the cooling stack to reject all the heat. (Turn the A/C off, and everything returns to normal)
Which makes me wonder if going BACK to R-12 wouldn't be a bad idea....unless having better rejection of heat means the cooling stack would be overwhelmed at 85, instead of 90 degrees?
Which makes me wonder if going BACK to R-12 wouldn't be a bad idea....unless having better rejection of heat means the cooling stack would be overwhelmed at 85, instead of 90 degrees?
This is why I kept my A/C system on R-12 when I rebuilt it last year. Its been in the upper 90's with low 100's on the road around here this summer and the system works great.
As far as C4's having A/C problems, its reflective to remember that most of the C4 OEM A/C systems lasted 20+ years many with the original Freon charge.
Le Mans Master
Joined: Jul 2007
Posts: 5,043
Likes: 8
From: Tampa Florida
If you can find'em post your source and part numbers for the standard shaft seal, case seals, bearings.
Use some penetrating oil on the hardware before you begin. You'll more than likely still need a 6mm allen attached to an impact gun to get the hardware off/out of the compressor case.
Race Director
Joined: Sep 2001
Posts: 14,685
Likes: 753
From: NEwhere Ohio
I recommend you do, with your AC, like you do when the cats get clogged up:
Remove the part for increased performance/
I yanked the A/C and installed an A/C delete pulley in '05 on my vert.
Never been happier.
Of course my thinking was 'its a vert, if Im driving it the top should be down at which point AC is useless'.
Remove the part for increased performance/
I yanked the A/C and installed an A/C delete pulley in '05 on my vert.
Never been happier.
Of course my thinking was 'its a vert, if Im driving it the top should be down at which point AC is useless'.
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
Nippo 10PA20C shaft seal kit is $21 or so at www.ackits.com - I wouldn't bother with the R4, though I'm sure there's a kit for it too.
Never had to use an impact wrench on a compressor. Shaft bolt is 10 ft/lbs and anything more has crushed the shaft seal. Manifold bolts are the same. Going ape on these aluminum cases will distort if not break parts, squish o-rings, etc.
Aux fan on these early Years isn't tied into a/c or even necessary, though to use it, you will need to splice the driven side of the Relays so that they're under control of the Pressure Switch. Also consider an alternator upgrade as both fans plus full Blower will overwhelm output and once it's below battery, everything will slow down and pretty much make the mod worthless; ie, it'll overheat and it won't be making cold air.
Never had to use an impact wrench on a compressor. Shaft bolt is 10 ft/lbs and anything more has crushed the shaft seal. Manifold bolts are the same. Going ape on these aluminum cases will distort if not break parts, squish o-rings, etc.
Aux fan on these early Years isn't tied into a/c or even necessary, though to use it, you will need to splice the driven side of the Relays so that they're under control of the Pressure Switch. Also consider an alternator upgrade as both fans plus full Blower will overwhelm output and once it's below battery, everything will slow down and pretty much make the mod worthless; ie, it'll overheat and it won't be making cold air.
Le Mans Master
Joined: Jul 2007
Posts: 5,043
Likes: 8
From: Tampa Florida
Nippo 10PA20C shaft seal kit is $21 or so at www.ackits.com - I wouldn't bother with the R4, though I'm sure there's a kit for it too.
Never had to use an impact wrench on a compressor. Shaft bolt is 10 ft/lbs and anything more has crushed the shaft seal. Manifold bolts are the same. Going ape on these aluminum cases will distort if not break parts, squish o-rings, etc.
Aux fan on these early Years isn't tied into a/c or even necessary, though to use it, you will need to splice the driven side of the Relays so that they're under control of the Pressure Switch. Also consider an alternator upgrade as both fans plus full Blower will overwhelm output and once it's below battery, everything will slow down and pretty much make the mod worthless; ie, it'll overheat and it won't be making cold air.
Never had to use an impact wrench on a compressor. Shaft bolt is 10 ft/lbs and anything more has crushed the shaft seal. Manifold bolts are the same. Going ape on these aluminum cases will distort if not break parts, squish o-rings, etc.
Aux fan on these early Years isn't tied into a/c or even necessary, though to use it, you will need to splice the driven side of the Relays so that they're under control of the Pressure Switch. Also consider an alternator upgrade as both fans plus full Blower will overwhelm output and once it's below battery, everything will slow down and pretty much make the mod worthless; ie, it'll overheat and it won't be making cold air.
Was only talking about disassembling the 6mm allen compressor case bolts with impact tools - nothing more.