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I did not buy a "Red Dot" Sanden compressor, but I did buy a U4311 which is supposed to be the correct part number.
Problem is the pulley supplied with the Red Dot kit has a 3/8 belt groove just like the rest of the belt grooves on the HMMWV, the belt supplied is a 10Axxx which is 10MM wide.
The compressor has an A groove (1/2"/13MM) pulley, this pulley is too wide to be correctly driven by a 10MM wide belt.
I have consulted with a nation wide distributor of Sanden compressors and he tells me the A groove pulley is the narrowest (groove) pulley offered by Sanden, And that my part number is supposed to have an A groove pulley so unless Sanden made pulleys specifically for Red Dot then all kits have the A groove pulleys.
SO has anyone else had these issues?
I have noticed many replacing the alternator belt with the 11A1625 or 7460 belt, these are 7/16"/11MM belts and do ride a little higher in the pulleys but probably not enough to be a problem.
I am also wondering if my compressor actually has an A groove pulley, a 1/2" belt does seem to fit correctly, I measure the flat area in the bottom of the groove at about .25" If anyone has a factory Red Dot compressor please measure that area and get back to me.
On another note I did order 6, XL7460 (Gates) belts (the ones that came with the 200A kit were hopelessly and permanently twisted) hoping to find a set of three that match, 3 came in yesterday and the good news is that 2 of them had the same date code and match perfectly, hopefully of the three coming today there will be a combination that gives me three matching date codes.
Problem is the pulley supplied with the Red Dot kit has a 3/8 belt groove just like the rest of the belt grooves on the HMMWV, the belt supplied is a 10Axxx which is 10MM wide.
The compressor has an A groove (1/2"/13MM) pulley, this pulley is too wide to be correctly driven by a 10MM wide belt.
I have consulted with a nation wide distributor of Sanden compressors and he tells me the A groove pulley is the narrowest (groove) pulley offered by Sanden, And that my part number is supposed to have an A groove pulley so unless Sanden made pulleys specifically for Red Dot then all kits have the A groove pulleys.
SO has anyone else had these issues?
I have noticed many replacing the alternator belt with the 11A1625 or 7460 belt, these are 7/16"/11MM belts and do ride a little higher in the pulleys but probably not enough to be a problem.
I am also wondering if my compressor actually has an A groove pulley, a 1/2" belt does seem to fit correctly, I measure the flat area in the bottom of the groove at about .25" If anyone has a factory Red Dot compressor please measure that area and get back to me.
On another note I did order 6, XL7460 (Gates) belts (the ones that came with the 200A kit were hopelessly and permanently twisted) hoping to find a set of three that match, 3 came in yesterday and the good news is that 2 of them had the same date code and match perfectly, hopefully of the three coming today there will be a combination that gives me three matching date codes.

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