Question on Stripped Serpentine Belt Tensioner Bolt...

smokedvw · October 26th, 2010, 22:09

Today while replacing my alternator I was putting the serpentine belt tensioner back on and stripped the thread which the longer bolt goes into... (the top one in this picture).

I am assuming I am going to have to go with a helicoil kit to fix this. The bolt does not seem to come out on the other side to use a nut and it looks like a helicoil is the only way. We pulled out the windshield washer container and figured it might be to difficult to get a small drill in this area and may have to create a manual one with the kit and a socket set.

Is this going to be a problem to not fix this bolt and rely on the other 2 to hold the tensioner? It seems like this bolt takes more of the load for the tensioner.

I was looking for any suggestions from anyone who has had to fix this at this location before.

A hard pipe (I believe AC line) runs at the bottom of where the windshield wiper holder is and because of this its hard to get a drill at a level position with the hole that the bolt goes into. I have 2 small makita drills and the driver looks like it would be just small enough but the smaller drill hits the line and cant get level.

Joester · October 26th, 2010, 22:32

mine did the exact same thing when i was replacing the alternator. its been running fine on 2 bolts for about 5 months now, i forgot which one of mine stripped though.

I thought about it too, and i think a helicoil would be the only plausible solution.

I figure when it does break ill say "aww shucks" get AAA tot ow me home and Helicoil it. im kinda relying on luck to let it break someplace and some time convenient

EDIT: i think we actually stripped the same bolt. thats the one that part of the bolt shaft is smooth before the threads appear right?

if you do end up helicoiling it tell me how it goes.

wolfman79 · October 29th, 2010, 07:10

I just stripped the same bolt while installing my new tensioner! Has anyone checked to see how far the threaded hole extends into the engine block?...maybe a slightly longer bolt could be used to reach good threads?

Joester · November 1st, 2010, 12:28

IIRC the bolt goes all the way through, it actually doesnt go into the engine block i dont think, it goes in an aluminum part mounted to the engine block, but its such a giant part, you might as well just take out the engine to replace the part that bolt goes into.

VW Petrolero · November 1st, 2010, 14:33

Quote:

Originally Posted by smokedvw

Today while replacing my alternator I was putting the serpentine belt tensioner back on and stripped the thread which the longer bolt goes into... (the top one in this picture).

I am assuming I am going to have to go with a helicoil kit to fix this. The bolt does not seem to come out on the other side to use a nut and it looks like a helicoil is the only way. We pulled out the windshield washer container and figured it might be to difficult to get a small drill in this area and may have to create a manual one with the kit and a socket set.

Is this going to be a problem to not fix this bolt and rely on the other 2 to hold the tensioner? It seems like this bolt takes more of the load for the tensioner.

I was looking for any suggestions from anyone who has had to fix this at this location before.

A hard pipe (I believe AC line) runs at the bottom of where the windshield wiper holder is and because of this its hard to get a drill at a level position with the hole that the bolt goes into. I have 2 small makita drills and the driver looks like it would be just small enough but the smaller drill hits the line and cant get level.

Just do the Helicoil repair and you 'll be OK THAT BOLT DOES MOST OF THE WORK IN KEEPING THE TENSIONER IN PLACE.
Later

iantyler · November 1st, 2010, 17:47

oof very tight squeeze in there. good luck on it!

DanG144 · November 1st, 2010, 18:29

Ask DidJettarun for some tech tips on this.

He had a stripped bolt, and did two helicoil repairs.

Dan

mike92105 · February 3rd, 2011, 14:59

I just did the same thing,stripped the longest bolt on the tensioner. At first I thought it was a helicoil that the factory put in because it came out looking like a helicoil. I've never done a helicoil so I guess this will be a new skill set for me. I thought about just drilling the hole all the way through as it appears the bracket is just aluminum, but figure I'll try the helicoil first and if that doesn't work I can always drill it all the way through. I'm pretty sure I never put more than 25 ft/llbs on the socket wrench. Still not sure why the factory didn't put more threads in there knowing it was aluminum and therefore not very strong.

DidJettarun · February 4th, 2011, 13:29

Yep the bolt brings out the threads with it and it looks just like a failed helicoil...And yes when I did the repair I used two helicoils...one for the failed bolt and one for the good one that I drilled out by mistake talking to DanG144 while I was working...LOL

mike92105 · February 4th, 2011, 14:39

Just finished, the bolt is a 8mm 1.25 pitch 3.25 inch long bolt. When doing a heli-coil you will need a 21/64 drill bit and an angle drill adapter. It was my first heli-coil so I took my time. Needless to say it took me a while, thought I busted out the tang, but on inspection with a mirror it was still there, several attempts later, gonzo! I was a little hesitant to put too much torque on it when I was done, does anybody know what the torque should be on this bolt?

mike92105 · February 4th, 2011, 14:41

The good news is the tensioner does not have to come out. You can drill and heli-coil right through it.

r72gsaol · February 28th, 2011, 17:11

Found this bolt missing on my beetle while doing the timing belt.

I just tapped it out to 3/8x16 SAE thread. The tap will go right into the existing hole with a little work and the hole in the tensioner needs to be opened up just a hair to 3/8.

Easy quick 30 minute fix.