Serpentine Belt Failure Redux

[Fred Munro]

Doh! (smack to the forehead)

Pardon me while I castigate myself.

Doh! (smack)  Doh! (smack)

Ahh, the catharsis....

As you may gather from the above, there was a reason my new s-belt failed.
When you install the hydraulic pump pulley back to front, it is 1/4" out of
alignment with the other pulleys to the front side. There is a nice "FRONT"
stamped on one side of the pulley. Somehow I managed to miss that, didn't
notice it was out of alignment when I visually checked the pulleys, didn't
notice it when I installed the belt, and still didn't notice it when I did
my final job check of the re-installed nuts, bolts, & parts (although the
guard was on at this point). I even didn't notice it when I watched the belt
run at idle, but I might have if the guard had been off. Doh!
I did notice it when I pulled the guard today and saw the remaining strip of
belt was in the back three grooves on the hydraulic pump pulley and in the
front three grooves on all the rest.
I think the belt must have run up on the back flange of the hydraulic pump
pulley and eventually split. Not the fault of the belt, but pilot error as
they say.
However, it was not a total loss. I did learn a few things about s-belt
failures.

Talking to the Service Manager at the dealer, I learned:
1. S-belts do fail soon after installation if you get a bad one.
2. He has seen them take out t-belts and bend valves when they fail (there
you go, Dave, your friend isn't the only one).

Replacing the s-belt today I learned:
1. The danger to the t-belt is real. There was lots of rubber and s-belt
fragments inside the t-belt cover. How it got there I haven't a clue since
everything is closed up by the upper and lower covers.
2. I did come up with a s-belt replacement method which avoids the Bentley
procedure of removing the fan. After much struggling, I also came up with a
simple method of routing the belt. This is not a job you will be doing on
the roadside unless you are truly desperate and don't mind getting really
dirty.

Ah well, back to the dealer to tell them they don't owe me a warranty belt.
Instead it appears I owe them a bit of cash for the new belt they
supplied... Ahh, the embarrassment....

Watch your s-belts. It looks like breaking an s-belt can have the same
result as breaking a t-belt.

Fred Munro
'94 S4 (give me a belt)