Alternator and power steering belts keep coming off

[82_k10]

Truck is an 1982 non a/c truck with a 350. Had problems with alternator belt squeaking after replacing heads. Changed the bracket for the alternator still squeaked. Changed the alternator and it finally quit squeaking but once I took it for a little test drive the belt popped off completely. Tried adding washers and spacers to areas of the bracket to get it to line up better on the water pump pulley but it’s pretty close. Even had a straight edge on the pulleys and they touch both sides of both pulleys. I’ve tried having the belt looser, tighter nothing seemed to work. One day belt popped off and I looked under the hood and the power steering pump belt was crooked. It’s hard to explain but it was still in all grooves of the pulleys and working just fine but it was crooked. I took the belt off put it on correctly and put the alternator belt back on. And they both popped off. Put both back on and they popped off again. Unbelievable. Tired of messing with it, need help. Sounds like something I’m doing wrong but I feel like putting a belt on is pretty simple. Thanks

 

[fast 99]

Pictures would help. Could be mismatched diameters between the crank, WP and PS. Misalignment won't help. PS pully should be flush with pump shaft.

 

[82_k10]

Pictures would help. Could be mismatched diameters between the crank, WP and PS. Misalignment won't help. PS pully should be flush with pump shaft.

I’ll try to get pictures as soon as I can tomorrow.

 

[Bennyt]

No other changes other than heads?

Did you add headers by any chance and not install the stabilizer bracket?

Do you have the back bracket on the p/s pump?

Once you have everything lined up, I'd put an indicator and check the run-out, ensure pulley isn't bent or out of round. Make sure grooves are clean and belts are new.

Also, use welding rod to line up pulleys and bend/ wrap it to route like a belt.

 

[82_k10]

You must be registered for see images attach

You must be registered for see images attach

You must be registered for see images attach

 

[82_k10]

No other changes other than heads?

Did you add headers by any chance and not install the stabilizer bracket?

Do you have the back bracket on the p/s pump?

Once you have everything lined up, I'd put an indicator and check the run-out, ensure pulley isn't bent or out of round. Make sure grooves are clean and belts are new.

Also, use welding rod to line up pulleys and bend/ wrap it to route like a belt.

We did put headers on it but that was before the heads were even changed. The ps bracket had a piece that bolted onto the exhaust manifold which is why we bought a new ps bracket which worked fine until very recently. The original alternator bracket had nothing that bolted to the manifold.

Pictures are ps and alternator original brackets

 

[82_k10]

Forgot to say that a while back I noticed the crank pulley wobbles a tiny bit while running. Don’t know if that matters since it worked so long with it like that.

 

[fast 99]

Hard to tell from pictures, are the 2 sheaves on the water pump the same diameter and are the 2 sheaves crank the same. If they are not one belt has to slip.

 

[Bennyt]

Can you physically move the PS pump or alt fore/aft by hand?

 

[82_k10]

Hard to tell from pictures, are the 2 sheaves on the water pump the same diameter and are the 2 sheaves crank the same. If they are not one belt has to slip.

You must be registered for see images attach

This is the crank pulley it is a little hard to tell but it has three slots or sheaves I think you called them. It has 2 sheaves that are the same diameter as the water pump pulley and a third towards the front that is slightly larger. Never noticed this before but it looks like the larger sheave is not attached to the actual pulley and is just bolted on instead.

You must be registered for see images attach

You must be registered for see images attach

I hope you can see the picture fine but the front sheave (larger one) of the crank pulley aligned with the front sheave of the water pump which goes to alternator. The middle sheave of the crank (same diameter of both water pump sheaves) lines up with the second sheave of the water pump and goes to the front sheave of the ps pump. Now In the first picture the last sheave of the crank pulley lines up with the 2nd sheave of the ps pulley but doesn’t line up with waters pump. So I understand what your talking about with the different diameters because it would change the ratios and they would be fighting each other but how could I fix this. Get a new crank pulley? Thanks

 

[82_k10]

Can you physically move the PS pump or alt fore/aft by hand?

Once the belt is on and tightened everything is solid.

 

[fast 99]

That wont work. Just went out to and took some pictures. Truck is a 85 K20 with AC so it's a little different. All 3 crank pully sheaves are the same diameter. Both groves are same on the WP except the added air pump pully. Last picture is crank pully from underneath.

Appears to me either the crank pully or WP pully is wrong on your truck. I remember seeing WP pulleys with 2 different diameters. May be someone else has an idea what the applications are.

 

[Copymutt]

Pulley diameter is not the only factor that can cause rotational mismatch. Belts must be the same contact pitch and width. That last shot under the crank, front belt looks a little canted.
Ive set up accessories from scratch and fasten archery arrows to the face of the pulleys. Stand back a ways to sight in alignment.

You must be registered for see images attach