Engine Drive Belts

Paul Steinberg

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Today, I looked up the OEM (original equipment manufacturer) part numbers for my 1969 Cadillac Commercial Chassis Ambulance engine for a reference point. I then went to Rockauto.com and put in the information for my car, and found the belt part numbers. To my surprise, the part descriptions differed from the original sizes listed in the Cadillac parts book. I then went to the Gates.com website, and searched by application, only to find the same information. Then I tried putting in the OEM part numbers, and it came back without any changes. Knowing that 1/2" or 3/4" can make the difference between a belt fitting properly, I placed a call to a friend at a local auto parts store. I gave him the belt dimensions from the parts book, and he was able to give me the replacement part numbers within a very close tolerance. Only one of the belts that was "recommended" by the Gates website actually was an acceptable substitute. If you need replacement belts, I suggest that you try to find the original factory specification size, and have that converted to a belt number. My friend explained that some sizes are not that popular, and the catalogs today, will round the size the belt up or down so the stores don't have to carry such an extensive assortment.
For the 1969 / 1970 commercial chassis ambulance, the belt numbers are as listed below. The only differance between the ambulance and the hearse is the alternator (generator) belt length is different. I didn't have that part number available to me, so it isn't listed below.

A/C & Power Steering pump with 2 belts.
1602011 (GM)
7590 (Gates)
3/8" x 59 1/2"

Generator
1489483 (GM)
7650 (Gates)
15/32" x 56 7/16"

A.I.R. Pump
9433744 (GM)
9463 (Gates)
15/32" x 46"
 
The differance is in ether the crank shaft pulley or the fan/water pump pulley. I can't recall with out comparing what I have. But I know when I removed pulleys from my two parts cars, both 73 M-M's, there were differant pulleys on each car.
 
it still falls back on who changed what and when. as the cars got into the later stages of they work life or there next live, they could really be cobbled in an attempt to save money and get one more round of of it. I have said it before and I'll say it again the hardest part of any restoration is returning the car back to stock. undoing some of the weirdest things that some mothers child has done to the car. for who knows what reason.

the production changes and difference between ambulances and hearses and limos is understandable confusing sometimes but you can usually reason out why. but the mix matching of parts from other cars and aftermarket sources is really a mystery. it's so much easier to just put it back right the first time. that is unless you have a 68 with factory air and the rust in the gas tank has plugged the filter that is no longer available so no you have no return hose back to the gas tank. now what.
 
unless you have a 68 with factory air and the rust in the gas tank has plugged the filter that is no longer available so no you have no return hose back to the gas tank. now what.

Ed is SO very right on this one. The fuel filter on the '68s with factory air is a specific, ONE year only part. These filters are not available in any auto parts store or dealer, no longer made is what I kept getting. After seeing AC Delco ones one Ebay start at $100 each, I happened across a listing by chance for 4 of said fuel filters made by Carter. I got all four of them for $100.
 
now I know who to ask if I have trouble again. it the stair parts that one needs to get a replacement one of what was around yesterday might not be tomorrow and they are not fresh fruit they will keep with a minor amount of care. on doesn't have to get everything at once but just a little at a time.
 
Today, I looked up the OEM (original equipment manufacturer) part numbers for my 1969 Cadillac Commercial Chassis Ambulance engine for a reference point. I then went to Rockauto.com and put in the information for my car, and found the belt part numbers. To my surprise, the part descriptions differed from the original sizes listed in the Cadillac parts book. I then went to the Gates.com website, and searched by application, only to find the same information. Then I tried putting in the OEM part numbers, and it came back without any changes. Knowing that 1/2" or 3/4" can make the difference between a belt fitting properly, I placed a call to a friend at a local auto parts store. I gave him the belt dimensions from the parts book, and he was able to give me the replacement part numbers within a very close tolerance. Only one of the belts that was "recommended" by the Gates website actually was an acceptable substitute. If you need replacement belts, I suggest that you try to find the original factory specification size, and have that converted to a belt number. My friend explained that some sizes are not that popular, and the catalogs today, will round the size the belt up or down so the stores don't have to carry such an extensive assortment.
For the 1969 / 1970 commercial chassis ambulance, the belt numbers are as listed below. The only differance between the ambulance and the hearse is the alternator (generator) belt length is different. I didn't have that part number available to me, so it isn't listed below.

A/C & Power Steering pump with 2 belts.
1602011 (GM) = Discontinued by GM
7590 (Gates)
3/8" x 59 1/2"

Generator
1489483 (GM) superseded number = 943918 = 1490175 = Discontinued by GM
7650 (Gates)
15/32" x 56 7/16"

A.I.R. Pump
9433744 (GM) 7/16 x 46" Still a current part number in the GM catalog
9463 (Gates)
15/32" x 46"


I was asked for this information today, so I did a search to find it. One last time.. For all those that have these cars, make a note of this belt information. One day I might not be able to remember how to find it... Paul
 
All i could come up with was the 7590 number. But as i remember there was so little movement in the alternator the belt had to be rolled on.
 
Pictures of the belt locations from the 1969 Cadillac Service Manual. I believe that the 1970 is different because it doesn't have an air injection reactor pump commonly known as a AIR pump.
 

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I will have access to a 1970 Cadillac parts book later today, and I should be able to get the correct part numbers for the 1970 Commercial Chassis belt part numbers, which I believe will be different than those for the 1969, because of the elimination of the AIR pump.
 
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