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View Full Version : Bolt / torx? size for the belt tensioner?


JFerg65
03-01-2009, 08:19
Does anybody know off the top of their head / memory what size torx / allen is needed to remove the belt tensioner assembly? I've got every size under the sun except this one! This should be a ten minute job!!! The sun is finally out and this needs to get done today.
JFerg65
03-01-2009, 08:56
Here is the answer for anybody in the future.... T-55 torx
JFerg65
03-01-2009, 09:47
Total time of job once I had the correct torx bit, 30 minutes and that is tools away. Now to get the old pulley off and rebuilt / replaced and I've got a spare to carry. Does anyone happen to know if the pulley with the outside ridges are any better or worse than the smooth pulley?
DmaxMaverick
03-01-2009, 18:23
The pulleys are function-specific. Grooved pulleys are for use with the inside of the belt (grooved), and the smooth pulleys are for use with the outside of the belt (smooth). Using one for the other will cause early belt failure, and sometimes very early. Do not use a smooth pulley for the grooved side of the belt, or vice versa.
simon
03-01-2009, 21:02
I think DMAX mis understood your question. there are indeed smooth pulleys with a flange on the both sided and designed for use on the flat side of the belt. they are used on the later models with the reverse running HO water pumps with a non flanged pully. i think it dont matter one way or the other as long as the flanged pulley is not interfering with the Water pump pully if it has ridges too.on a 96 and up i would use the flanged tensioner pulley to keep the belt aligned with less change of it flipping of.
DmaxMaverick
03-02-2009, 01:52
If your belt is coming off of a smooth pulley, something isn't aligned, or the pulley is bad. It should run true. The "flanged" pulleys won't stop a belt from running off or rolling if it is misaligned. Even with the "flanged" pulley, the belt will run off or roll if it isn't true. Plastic pulleys have the rolled edge because they can flex more than steel, and the raised edge helps stiffen the pulley.
JFerg65
03-02-2009, 04:43
Thanks everybody

Sorry about the confusion on the pulley type. This is on my 96 2500 Burb. It did appear to be one of the change overs to the HO water pump. Late year 96?? Anyhow it did have the pulley with the two outside "flanges" or lips. My new AC Delco one that I installed yesterday does not have the lips or flanges. It tracks true and the truck sounds a hole lot better.

I found a bearing to rebuild the one that went south on the shelf at NAPA.... they had two brands one being a little better built. Anyhow, I came home after the test drive and rebuilt the original and now it sits in the truck tool box with a new SERP belt... Just in case.
simon
03-02-2009, 19:55
If your belt is coming off of a smooth pulley, something isn't aligned, or the pulley is bad. It should run true. The "flanged" pulleys won't stop a belt from running off or rolling if it is misaligned. Even with the "flanged" pulley, the belt will run off or roll if it isn't true. Plastic pulleys have the rolled edge because they can flex more than steel, and the raised edge helps stiffen the pulley. There are steel tensioner pulleys with a raised edge too, got that on my 98. got a steel waterpump pully with raised edges on my 95.These ridges are not to stiffen the pullys up altough it helps.
I agree however that belts have to run true to start with