12 Months ago I recently acquired another S4 FC at work from one of our customers. And one very odd thing I found in the history is repeated drive belt failure. The belts (alt and p/s) continually loosen up. This has had me stumped. And everyone who has worked on the car seems to have some weird idea as to why it is, and they've all been wrong.

Since owning the car, I have installed an S5 alt, a dual sleeve alt pulley, and replaced (Bando) belts multiple times because they keep loosening up to the point to where they're so stretched I can't tighten them anymore. Each time I am checking for proper belt tension and even having other guys double check tension (because I keep having this dang issue I'm second guessing myself). I had this sort of problem on a Cobra Mustang super charger serpentine belt once because the alt shim/spacer was missing so I was sure to check pulley alignment with the main, p/s pump and alt. Everything is good. It's not just alt belts and it's not just p/s belts, it's all of them, and they wear at about the same rate. So the only variable would have to be the main, right??

I have now wondered if the stationary gear bearings are failing, causing abnormal wear on my belts. I know that over-zealous tightening of the belts has been known to cause this in the past. Anybody else experience this?

 

Replace the water pump. Remove all pulleys and thuroughly clean them. Check for oil leakage. Try converting the air pump and alternator swivel tensioner bolts with studs and use a locking nut so you can put some real torque down without stripping the aluminum threads. The bolts just dont tighten enough and eventually loosen.

 

Replaced waterpump about 2k miles ago (no change) at that time I cleaned the pulleys. Currently not running an air pump. But it was when it came in. That didn't change anything either.

Would it help if I used lock-tight on the pulley bolts?

 

Something is out of alignment then. How is the condition of the fan? Missing any blades? AP is supposed to be a tensioner. Dual belts never are the exact same length so it could be a problem there.

 

I did all of this about a month ago on a buddy's car. Cleared it right up.

 

do you have all 8 bolts on the Fan pulley?
I know that 4 go to the pulley,and the other four are for the Clutch fan,but If you take the clutch fan off it is best to still have bolts there,as it will tend to make the pulley wobble.
My WP started weeping because of this.I replaced the pump and added the extra bolts.

 

I'm having this issue. My alternator is at the maximum now and it the belt is definitely stretching. I also have tons of belt dust all over the engine bay.

how do I check that everything is in alignment? It looks like the alternator doesn't really have any sort of adjustment other than tension...

 

Does your alternator have the spacer washer? I swapped to manual steering too so I removed the front bits of the main pulley. Don't know if that helps.

 

Yes my fan is in good condition, all the bolts are present. I have not put my hands on them yet. I bought a special wrench just for those so they aren't that bad for me. I will have to check.

I believe I have the spacer there. I can't see why I would have removed it but it's not a bad idea to double check.

And this problem was present prior to switching to dual belts. Saw no difference after switching. Mainly went to dual belts because they keep loosening up and I don't want to deprive my car of any help from the alt. I do keep a pretty close eye on these belts but the big thing to remember here is the P/S belt is doing this too. The alt is not the variable.

 

So the belt becomes loose but no evidence of damage? So just stretching?

 

Yes, and I know usually a little stretch is okay. Then 1 regular adjustment is the fix. If not, use better quality belts. I'm using BANDO belts and as far as I know it doesn't really get better than that. Especially on a stock NA car.

 

Can not having the spacer washer there cause the alt belt to continually squeal and shred off? I replaced my alternator tonight and cannot fix my problem. The only thing I can think of is that I didn't realise there was a washer there when I removed the alt. Maybe it's time to break out the heavy duty magnet...

I have to get this problem solved tonight. Does anybody know the dimensions of said washer?

 

That spacer washer is about a 1/2 inch thick and goes at the back of the alternator.It holds the alternator up close(Front) to the Water pump housing(?? or what the ears are to set in/on).

Order is like this: Bolt going through at front/ alt ear/mount/spacer/alt ear /rearbolt

When you remove that washer,it falls about Center iron/lower manifold area.You almost have to be a damn Gymnast to get it!

Now,IF that washer goes MIA then you can always use a couple flat washers to make the difference up in the space.The Split collar in the back ear of the alternator should compress enough to tighten the alt down to the mount.

If anyone has replaced your alternator,it could happen that they did not put a bearing spacer in to bring the pulley out to go in line with the rest of your system.
This is sometimes a mistake,especially with the FD alternator install.
When you install the alternator and have it in position you should look at the belt and make sure that the belt is straight with ALL pulleys.

 

Now, I have an S5, which I found this morning does not use a washer? However, I installed my alt with a BRAND NEW FC unit. However I do not have a laser pointer to check if I'm in line. If it's off, it's off by a mm. I get even wear on the grooves of my pulley, so I don't know. Inside the alt ears to the mount, there is a thick washer on the inside of the ear, but I was wondering if there was another.