AC Compressor Belt

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texasmike

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I recently installed a new Murray (manufactured by Four Seasons) compressor and accumulator along with the specified Gates 7555 v-belt. Everything else in the cooling system is original. I adjusted the belt tight but not real taut. The AC worked great, real cold air and no noises. 550 miles later, the AC belt started squealing after driving awhile and rising engine compartment temperature. I re-tightened the belt and am now out of adjustment room. The noise is gone but if the belt stretches again, I will have to replace it with a new belt. I believe the 7550 belt is 1/2" shorter. Are these belts not made as good as they use to be or am I the only one having this issue?
 

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squarelyfe

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I'd find a slightly shorter belt, then retension. Some stretching is normal. Are you sure the bolt or nut didn't loosen up? The rising temps aka heat will naturally soften the rubber allowing for some stretch especially if over tensioned. I've also found belt dressing to be your friend.
 

texasmike

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I had to loosen three adjustment bolts and two pivot bolts to get it to move so I don't think it was a loose bolt. Belt dressing is a good point, however. Thanks.
 

Snoots

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That belt is sitting WAY TOO LOW in the pulley. Consider getting a wider belt.
 

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That belt is sitting WAY TOO LOW in the pulley. Consider getting a wider belt.
i concur, you are likely eating small amounts, especially once it squealed, so that it had behaved as if its a longer belt, meaning less room to tension. does your compressor have a part number for a belt to use? does the groove your using to drive the compressor on the crank have the same dimensions to it like it sits the same in both pulleys?same with the water pump groove. if your belt , when new, is proper on the ac comp its possible the pulleys are worn or just are made for a different kind of belt.
 

texasmike

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The belt connects with the fan, crank and power steering pulley's and fits flush with the top of all three. I agree and it looks like the belt is too small for the compressor but the vendor says it specifies the 7/16" wide belt. I'm certainly not going to try to change the other pulley's to accommodate a wider belt. I guess I'll try to contact the manufacturer to see what they say.
 

AuroraGirl

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The belt connects with the fan, crank and power steering pulley's and fits flush with the top of all three. I agree and it looks like the belt is too small for the compressor but the vendor says it specifies the 7/16" wide belt. I'm certainly not going to try to change the other pulley's to accommodate a wider belt. I guess I'll try to contact the manufacturer to see what they say.
is the belt confirmed to be the right one, like perhaps a incorrect printing of the number on a different belt or wrong one provided
When the belt was new, how did it sit
 

scape

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Any update on this? I'm trying to find the right AC belt for my 85.
 

fast 99

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7550 will be about 1/2" shorter. Does appear belt is low in that pully but how deep is it in the others? Could just be the clutch/pully design?
 

texasmike

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7555 is the correct one for a OE stock setup, approx. 7/16" wide. I told the shop that replaced the compressor, I wanted to keep the original one but they turned it in as a core. All of the new OE compressors that I have looked at require a 1/2" (95 series) belt to fill the clutch pulley. The 7/16" belt fits the engine pulleys perfect, flush with the top. I am currently using a 9565 belt which works for the compressor but rides high on the remaining pulleys. This setup slowly eats up the sides of the belt and won't last more than about 2k miles.
I have been told that UAC in Mansfield, TX manufactures both a Piston (CO 11184MC) and a Scroll (CO 11184F) replacement R4 compressor that is correct. I plan to call them when I get a chance, and ask them how wide the pulley groove is at the top. I wonder if anyone has tried one of their compressors???
 

fast 99

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Does the narrow belt bottom out in the AC pully? If not, other than appearing wrong it should work. As you say the wider one will fail.
 

texasmike

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I’m not sure if it bottoms out but it stretches and starts to fray and then slips. It doesn’t take very long for the width to narrow.
 

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