Question- Replaced the waterpump today on my '01 TJ 4.0. Went to put the serp belt back on, and it was really loose. Huh? I grabbed the tensioner and it was "sprung" all the way in as far as it would go. Thinking hmm, the belt must have stretched three or four inches since I took it off, I bought a new belt, and what do you know, it's also too loose. It's loose enough to squawk off idle or when the lights or AC is on. What is going on here? Is there a way to "re-set" the tensioner? It has some marks on it and a little pin coming out the side but I'm not sure what it means. The Haynes is completely useless in this regard. (the pics are for a V-belt setup!)

I need a solution ASAP as this is my daily. <img src="/forums/images/graemlins/scared.gif" alt="" />

Thanks!

Brendan

If the pump came with a pully already on it check for size differences between the old one and the new one..
If You installed the pully yourself which is usual.. then the culpret is prolly typing questions..
I have seen all sorts of wrong belt installation from many different guys... However I have never seen a tensioner go bad when the belt was off of it.
Big Jim <img src="/forums/images/graemlins/pfft.gif" alt="" />

The pump did not come with a pulley. There is only 4 bolts on the pulley to hub mounting and it self-centers on the hub. I also compared the new belt to the old one and they are the same size. I've also verified the proper belt routing so that's not it either. Anybody know what the little pin on the belt tensioner does?

Thanks-
Brendan

I'm not looking at one this minute but I'd bet the "little pin" is the end of the tensioning spring.. I'd also bet you arn't pretensioning the belt while installing it.. How did you get the belt off in the first place? Did you insert a wrench and back off on the tension?
Big Jim <img src="/forums/images/graemlins/pfft.gif" alt="" />

Ah yes, I bet you are right about the "pin" being the spring. When I took the belt off, I used a pair of channelocks and grabbed the end of the tensioner, (opposite the pulley side) and twisted it clockwise until there was enough slack to pull the belt off the alternator. When I put it back on (and subsequently put the new belt on as well) I only needed to torque the tensioner about 1/4 inch and the belt slipped on. When I let go of the tensioner, it basically came back to the stop and is barely putting tension on the belt. I should have marked where the tensioner was positioned before I took the belt off so I'd have a better idea of what's going on. :P

What do you mean by pre-tension the belt?
P.S. I've installed probably a dozen serpentine belts on five or six different cars before and have never had this kind of problem. :P

Thanks,
Brendan

Channel locks? Can't you find a square hole for a socket wrench to fit into? Then you put all the torque on the wrench you can find.. then you install the belt.. I betcha everything is fine with the equpment and the installation is incorrect..
Big Jim <img src="/forums/images/graemlins/pfft.gif" alt="" />

yea thats what im guessing too is that he somehow routed it wrong