AC compressor does line up; new compressor

[adamj]

Trying to resurrect my AC system here.
I have an 87 suburban with rear ac.
The current system has been retrofitted to 134A, but does not currently work.
The compressor pulley does not line up (see pics below)
Is something bent? Is the wrong compressor in there?
I noticed some washers/shims, are those supposed to be there? How many?
I will very likely need to purchase a new compressor, which one should I get?

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[chengny]

Shims are not used from the factory but sometimes (due to modifications) they are necessary. In your case I would say that they are doing more harm than good. Take them out and see how the belt lines up.

An image of how your bracketing is supposed to be arranged:

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[VAL]

I have the exact same issue on my truck. It happened when I put the new compressor in, and I don't have any shims on it. But I did have to shim the power steering brackets a little. I've looked for answers online, and the only conclusion I have come up with, is that the new compressor is slightly different than the original. To this day, it's still not lined up perfectly. That being said, Its been working fine with no issues for a year now with that small tweak in the belt. I still, from time to time look online for more info on this dilemma, because it gnaws at me. Your the first person I've come across with that same exact issue.

 

[adamj]

Does anybody know the replacement AC compressor part number for the stock one (with rear ac)

 

[chengny]

The OEM part numbers are pretty much irrelevant at this point (12326202, 12326198, 12327548 are all good #'s).

You need an R4 compressor. As currently installed, yours is classified as a standard R4 - the other designation is "light weight" (the "standard" version is heavier and is longer in the axial plane). Any easy way to tell the difference is by the clutch housing.

Physical Dimensions

The width and height of of both R4 compressor versions have the same value of 6.98 inches.

The standard R4 is 6.92 inches long while the lightweight is slightly shorter at 6.14 inches. The differences in their lengths and weight are mainly due to their different clutches. Note that the clutches and their parts are not interchangeable between the standard and lightweight R4 compressors.

That difference in shaft length can cause misalignment issues (worse than you already have).


Two other characteristics to be aware of when (if) you decide to order a new R4 are;

1. The design of the sheave/pulley. For example you would want a single v-belt pulley as opposed to say a multi ribbed pulley.

2. The location of the electrical connector for the clutch solenoid. This position is described using the "o'clock" method. The two most common positions are 9 and 12 o'clock. It's hard to tell from your images but, it appears that your connector terminals are at the noon position.


The compressor you have now is the correct application. BTW - the style of compressor is more dependent on engine size than the design of the HVAC system. Bigger engines like a 454 will take an A6 compressor.

 

[adamj]

Ok! Standard R4 with 12 o'clock it is!

I'll be doing the radiator soon, and while I have access, I'll remove those washers and see if I can get it to line up properly. Can anything else go wrong that would cause a misalignment like that? I don't think the brackets are bent, but maybe somebody was torquing on it too much when tightening the belt and bent something?

 

[PrairieDrifter]

Those brackets are pretty solid. I think you should be pretty close to being straight after you remove those spacers, if not dead on it will be plenty close to live with. As long as you aren't throwing belts or wearing the belt out quickly, I wouldn't sweat it.

The pump on my burb was canted off a little bit and never had a problem, but I just took my a/c system out(too fancy for me to have a/c) haha

 

[chengny]

I think you should be pretty close to being straight after you remove those spacers, if not dead on it will be plenty close to live with.

What he said.


It seems as if someone went out of their way to cause that misalignment (horizontal angular). From what I can see, it appears that - had they not installed any shims at all - they end result would have been better (looks like it would have been nearly perfect). The problem is, I can't see the alignment on the other run of the belt - the section that runs from the bottom of the A/C compressor sheave down to the crankshaft sheave.

That might be a much worse situation, and adding those shims might have been an attempt to resolve a real bad bend. Kind of like; the lesser of two evils or splitting the difference between the two runs.

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[maxtwms]

Old thread but I have the same problem. I had my ps pump and ac pulleys maxed out and belt was loose. Had to go from 55.5" belt to a 55.125". Belt's tighter but I still have the angle issue. If I loosen the ac and tighten the ps, I can get the ac straight but it's out of plane.

I'm wondering if there's a way to shim the ac pulley outward...just the pulley. Is this possible?

 

[Obwonkonobe]

Old thread but I have the same problem. I had my ps pump and ac pulleys maxed out and belt was loose. Had to go from 55.5" belt to a 55.125". Belt's tighter but I still have the angle issue. If I loosen the ac and tighten the ps, I can get the ac straight but it's out of plane.

I'm wondering if there's a way to shim the ac pulley outward...just the pulley. Is this possible?

Id say no, because the ac pulley is actually built into the clutch, It would be more work reworking that (if its even possible) than to just get fancy with washers and cuss into the engine bay for a few hours

 

[maxtwms]

Bummer. I thought as much. Ive already shimmed the main brace off the heads by two washers. It's really weird it lines up like that. My belt's jumping around so I guess I'll keep tinkering and cussing till it settles down enough. Unfortunate.

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[adamj]

I have since replaced the compressor, and now it lines up perfectly. Amazing how having the correct part works...
So not sure I can help with a mismatched part or parts. Although mine ran for quite a while like that before I replaced everything, so it can be done.

 

[maxtwms]

I have since replaced the compressor, and now it lines up perfectly. Amazing how having the correct part works...
So not sure I can help with a mismatched part or parts. Although mine ran for quite a while like that before I replaced everything, so it can be done.

Can I ask which compressor you bought?

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[adamj]

I went through two actually, the first one was a dud, and did not work straight out of the box. That was a Four Seasons R4 unit. It fit properly, the belt and terminal clocking (12 oclock) lined up perfectly, but was not pumping. I ended up wasting refrigerant since I had to evacuate again and replace compressor and accumulator. The second one I bought, and it works very well now, was a GDP R4 (7511369). Both were new (not remanufactured) compressors and I was surprised that the more expensive Four Seasons compressor did not work. The GDP compressor kit (expansion valve for rear ac, o-rings, accumulator, orifice tube, and new compressor) was just shy of $200 including shipping. I purchased from Rock Auto. Nothing against 4 seasons, I'm sure they make good compressors, I just got unlucky. I charged the system with RedTek R12a and 525 mineral oil, and it blows very cold now, colder than modern vehicles I've driven in. You need to transfer mounting brackets to the new compressor, so don't throw that out. Also I put new female spade terminals for the clutch since my old ones were loose and corroded. Good luck! It was a lot of work and money, but so worth it in the end, don't give up!

 

[maxtwms]

Awesome. Thanks for that! I ended up grabbing a ToughOne compressor from Advance (which I've see alluded to as a 4Seasons product) since I could grab it today. Came out to about $155 after discount. I suppose if it doesn't work, I can always return like you did. Mine's been converted to R134a so Im going to try a can of AirPro Synthetic blend I've had laying around and see if that blows cold enough.

Do I need to purchase all the other gadgets like expansion valve, o-rings, orifice tube as well? Or could I just bolt it up and see what happens? Engine bay seems in pretty good shape otherwise, as far as I can tell.

Thanks again for the guidance.