AC delete on ‘96 5.7 Vortec - Belt questions

[EarthRocker82]

Hi all, new guy here so forgive me if this has been brought up before. I’ve had my truck for about a year now, got it after my father-in-law passed, and am wanting to fix an annoying issue. The truck at one point had the AC compressor deleted due to it probably locking up and had a dummy pulley put in place. The problem is that pulley squeaks like hell and no amount of spray lube on the bearings will get it to stop. Think 5 mins then squealing again. Tried two different sized pulleys with the same result. I’m wondering if there is a shorter belt that can be put on to just bypass the AC location altogether? If so, anyone have a part #? Thanks in advance!

 

[L31MaxExpress]

Hi all, new guy here so forgive me if this has been brought up before. I’ve had my truck for about a year now, got it after my father-in-law passed, and am wanting to fix an annoying issue. The truck at one point had the AC compressor deleted due to it probably locking up and had a dummy pulley put in place. The problem is that pulley squeaks like hell and no amount of spray lube on the bearings will get it to stop. Think 5 mins then squealing again. Tried two different sized pulleys with the same result. I’m wondering if there is a shorter belt that can be put on to just bypass the AC location altogether? If so, anyone have a part #? Thanks in advance!

The factory bypass used a ribbed idler pulley threaded into the boss on the compressor/power steering pump mounting bracket and the matching length belt.

This is an 8100 with the ac delete idler, but the Vortec SBC and 4.3L are the same. There is no way around having an idler in place to route the belt around the PS pump and over the water pump pulley. If GM could have saved $5 and eliminated that idler they would have. All the factory brackets I have had my hands on have the raised boss that is already threaded for the idler.

You must be registered for see images attach

 

[movietvet]

Welcome to the forum from Oregon.

When you tried the "2 different sized pulleys", did you change the belt size?

You have tried pulleys. How about a new belt to replace the existing one? If changing the pulleys and using the new belt, still has the noise, then I would change the belt, or the noise is coming from a different source.

 

[EarthRocker82]

I believe the pulleys were 125 mm and 127 mm. The belt is in good shape and hasn’t been changed and I figured the tensioner on there had enough give to support the larger size. I have isolated the squeak to the bearing in the pulleys, with both pulleys squeaking, not the belt itself. If I spray the bearings the squeaking stops, until the lube wears off.

I may be wrong, but it seems that whoever did the AC delete just found a bracket that works and stuck it on with a similar sized pulley to the AC compressor…?

 

[GoToGuy]

Is it the belt , or is it time for a new bearing in the idler pulley?
The pulleys need a certain amount of belt " grip " in order to actually be turned by the belt. That is provided by the amount of belt tension and the amount of belt contact with the pulley. For a good reason GM installed the idler, ( along for the ride ) as a better idea. Same belt sizes, same belt routing, same wear conditions. Don't shortcut it. Your oil trick isn't the fix. Look at the bearing for replacement.

 

[L31MaxExpress]

Is it the belt , or is it time for a new bearing in the idler pulley?
The pulleys need a certain amount of belt " grip " in order to actually be turned by the belt. That is provided by the amount of belt tension and the amount of belt contact with the pulley. For a good reason GM installed the idler, ( along for the ride ) as a better idea. Same belt sizes, same belt routing, same wear conditions. Don't shortcut it. Your oil trick isn't the fix. Look at the bearing for replacement.

Except GM built non ac trucks have a smaller idler, in a different postion and use a shorter belt. That is a cheap Dorman bypass setup.

 

[GoToGuy]

Still the the contact surfaces remained. Did they use an existing size idler that is in use already ? For me it's rare to see a non AC truck.

 

[454cid]

Idler pulley, Grooved, non-AC

More Information for GM GENUINE 12580772

You'll need a shorter belt for non-AC.

There should be a boss cast into the bracket under where the compressor used to mount. I assume it's drilled and taped, but I've never verified that on my own truck. You could also just get the compressor bypass pulley like what you've already got.

More Information for DORMAN 34174

More Information for ULTRA-POWER 34174

 

[Cadillacmak]

Hi all, new guy here so forgive me if this has been brought up before. I’ve had my truck for about a year now, got it after my father-in-law passed, and am wanting to fix an annoying issue. The truck at one point had the AC compressor deleted due to it probably locking up and had a dummy pulley put in place. The problem is that pulley squeaks like hell and no amount of spray lube on the bearings will get it to stop. Think 5 mins then squealing again. Tried two different sized pulleys with the same result. I’m wondering if there is a shorter belt that can be put on to just bypass the AC location altogether? If so, anyone have a part #? Thanks in advance!

Welcome from Alaska! Just in case your loaded with extra money, they have some nice belt systems here - https://www.cvfracing.com/

 

[L31MaxExpress]

Still the the contact surfaces remained. Did they use an existing size idler that is in use already ? For me it's rare to see a non AC truck.

New idler on the raised boss on the compressor bracket that I have seen drilled and tapped in every example. Those Dorman setups tend to be what they are. The 8100 I posted a picture of used the same idler setup. The 2005 GMT800 had the same I pulled a L31 from. IIRC the 7.4L Vortect bracket has the same raised mounting boss as well as the 6.5L diesel.

The Dorman pulley is likely sitting at an angle or at the wrong distance relative to the accessory drive. Saw that happen on the same junk Dorman setup on a S10 Blazer. Swapped it to the GM setup and the issue was resolved.

You must be registered for see images attach