98 GTP supercharger idler and tensioner pulley help

**BillA** · 05-16-2012

Hi! I've had no luck finding a definitive answer to this. I'm trying to replace the two supercharger idler pulleys (one smooth and one grooved) and the entire supercharger tensioner subassembly on a stock 1998 Grand Prix GTP. I purchased the correct parts, and a T50 bit and an E8 bit. I think the T50 is really supposed to be a T47, not sure if that makes a big difference. My first question: for each of those bolts, are they reverse or normal threaded? The E8 bolt seems like it's going to sheer off. Second question: the bottom smooth tensioner is very difficult to get at. A rachet with the torx bit on it is a bit too long to fit between the bolt and the inner fender. How can I get to this? I prefer to buy the right tools for each job if they exist. Thanks!

**Scottydoggs** · 05-16-2012

that would be the tentioner and the idler. the idler down low i got off with a t 50 iirc, on the end of a 3/8 ratchet, its regular threads. you should be able to walk into any parts store and ask for them.

the tentioner pulley maybe reverse threads, not sure never took that one off. and i don't know what a E8 socket is, im sure i haven't used one. the tentioner does come off as a whole unit by removing the bolt in the middle of it. you need a deep socket. and its regular threads as well.

**BillBoost37** · 05-16-2012

Tensioner bolt loosens in the opposite direction you go to release the tension. That way it tightens the bolt when you put the belt on.

I believe both are normal threads. It's the alternator bracket tensioner (accessory belt) that is backwards.

**BillA** · 05-16-2012

Thanks for the replies guys. Just to clarify, I want to remove the whole s/c tensioner (spring housing plus pulley), not just the pulley. The spring housing is held by a single torx bolt thru the middle of the spring housing, surrounded by that star shape. I'm pretty sure it's a TORX E8, but it seems like it can strip so easily (I tried it with great pressure in both directions with no luck) so I want to make sure I loosen it the correct way.

**Scottydoggs** · 05-16-2012

just had may whole tentioner off last month, mine was a 13 or14 or 15 mm deep socket, regular threads, righty tighty, lefty loosey.

**Dragon1972** · 05-17-2012

It is actually held on to the stud by a 15mm nut, to access it you need a thin wall socket.

**Scottydoggs** · 05-17-2012

thin walled nothing. i used a regular deep husky socket form a 25 dollar socket set, no special tools are needed at all. and its a bolt that looks like a stud.

**BillBoost37** · 05-17-2012

What's up with you guys..

It's a 13mm nut. Right down the center. The torx is the stud that goes into teh head and helps position the ICM/Coil pack bracket.

FWIW guard that nut with your life. it's not the average nut. It's a M10 x 1.5 nut in a 13mm head. Usually that large of a bore is a 15mm nut

**BillA** · 05-18-2012

Awesome! The s/c tensioner body was indeed held by a normally threaded 13mm nut! On my 2nd question, any advice for fitting the T47 TORX bit into the bolt holding the lowermost s/c idler pulley on? It's a very tight fit between the pulley and inner fenderwell. Rachet won't fit. Do I need to grind down the rachet and TORX a little bit?

**Scottydoggs** · 05-18-2012

screw it in by hand as far as you can, a 3/8 ratchet should fit. thats all i have so it has to work lol

**Dragon1972** · 05-19-2012

I agree with Scottydoggs, just a 3/8 ths ratchet.

**Swiggles** · 05-22-2012

take your battery out if its in the way. that one might be reverse threaded too.

**BillBoost37** · 05-22-2012

Originally Posted by Swiggles

take your battery out if its in the way. that one might be reverse threaded too.

The torx head bolt is found in the #9 location. All pulley bolts on a W body are regular threaded except #3. The only reason to reverse the thread on a bolt is because a tensioner would need to be pushed counter clockwise to release or tension a belt.

**cloead** · 09-20-2012

Originally Posted by BillBoost37

The torx head bolt is found in the #9 location. All pulley bolts on a W body are regular threaded except #3. The only reason to reverse the thread on a bolt is because a tensioner would need to be pushed counter clockwise to release or tension a belt.

ahhhhhhh

this would explain what happened to me today. went to swap out #3 tensioner pulley. broke it loose by turning it counter clockwise and it threaded somewhat normally all the way out. when i went to put the new pulley on i find that the threads are gone. ended up trying to retap it and no luck. put a bigger bolt in and snapped the housing.

whole new tensioner assembly for me =/

Thread: 98 GTP supercharger idler and tensioner pulley help

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