Unbelievable: Belt will not fit on new tensioner!

Silly question: is it possible to mount the belt tensioner in other that only 1 position?

IOW, can you mount it by rotating it 30 degrees or so clockwise and then putting in the holding bolts? Maybe this is your problem, maybe not. Just a WAG.

Lg

Hi Lawrence, thanks for asking and for your suggestion. No, the there are nine bolts which attach to the tensioner, and it can only fit one way. The pattern is pretty distinctive. I thought of that, and also whether I had reinstalled the PS pump correctly. But I was able to torque the three PS pump bolts, and the only way to do that is if they went correctly into the bores in the PS pump (otherwise the bolts would just spin repeatedly).

The thing is, the idler pulley on the new tensioner is positioned slightly differently on the tensioner, and I think this slight difference is the problem. But I definitely purchased the correct tensioner, supposedly, as it only works for two or three GM cars. Maybe I will have to buy and genuine GM one?? Or use a "universal" fan belt??

Julie

Julie,

I feel your pain. It may not matter in this case but I have had quality problems with parts I have bought from Advance Auto. I don't know why, but I no longer will buy any parts from them.

Another idea- did you replace the belt at the same time as the idler? I bought a serpentine belt one time from my CarQuest dealer. The belt was mfg by a well-know company, but it did not fit on my car. I just could get it on- very similiar to your issue. The solution was to exchange that belt for the "equivalent" belt made by another well-known company (I can't remember the two companies involved- it was 10+ years ago) and it fit perfectly!!

A work-around may be to see if you can buy another belt that is an inch or so longer than the specified belt. That way you would not need to replace the idler again.

Let us know the outcome.

Rich

"Julie P." wrote:

Unfortunately it 'really' sounds like you have the wrong part.....

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's

You will probably save yourself a lot of time and grief by just getting the part from GM. I know these are a pain in the ass to replace (why GM decided that the tensioner ought to be an integral part of the whole bracket is beyond me), but often aftermarket parts cause nothing but trouble. The other option would be to get a different belt that is just slightly longer.

Ian

Hi sdlomi. Thanks, but when I pulled the idler pulley off, there was only one bore for the bolt. Oh well!

J.

Thanks Rich. Yes, actually on the way to Advance Auto, the existing belt got torn due to the looseness. So I bought a new one there, and also put on the spare belt I had in my trunk, right in the parking lot!

The solution was to

Thanks. I compared the length of all the belts, and they appear to be the same. And neither one would fit on the new tensioner. I compared the old Dayco one with the new no-name one I got at the store. I have an old Gates one lying around--maybe I will try that too.

The only thing, is how will the parts person know which belts are just a little longer? Does their computer list belt lengths? Otherwise, it will have to be by trial and error, and they will not be willing to fetch new belts all day to measure the length just for me!

Julie

Thanks Mike! Yeah, I guess I'll be ordering one from the dealer tomorrow morning, and limiting myself to short, beltless trips if necessary. :) Doubt they will have one in stock.

Hi Ian, yes, I have resigned myself to this fact by now. The good thing is I now know all about installing PS pumps and hoses, so it should be easier this time, and a lot quicker.

The other thing is that one troublesome PS pump bolt actually fell deep within a recess near the engine mount bracket on my car when I finally got it out, and the magnetic pick-up tool only seems to have pushed it back somewhere invisible and out of reach! It's really lost. The PS pump is actually pretty tight with just the three bolts, so I am hoping the final one in the back is not critical. Besides, not having to deal with this final bolt makes removing and installing the pump a heck of a lot easier. :)

J.

They SHOULD have them ordered by length. If it's a standard V-belt, though, you can take it to an industrial parts place and ask them to match you a slightly smaller one. Those guys are much more apt to actually know belts.

If it's a weird profile and not a V-belt, you're probably stuck with the auto parts supply.

--scott

Thanks Scott! I will try calling then tomorrow, and if Advance does not have it, maybe try NAPA or Carquest, since their parts people know more. Might save me from having to reinstall a GM belt tensioner! Then maybe see if an industrial parts place has one. Do you or anyone else know what they would be listed under in the yellow pages? Machine shops? Industrial supply?

Julie

The tensioner, or some other pulley, will have a tension adjustment. This could be a screw drive, or simply a bolt. There might be a lock bolt that has to be loosened before the tension adjustment can be done. Many a time, I've found that a new belt is too tight simply because the tension adjustment is way out having been correct for the old belt. You adjust it all the way in , install the new belt, then tension it out so that you have 1/2" play on the longest span. a couple of days later, you check, and it is usually too loose, so you tension it again. This is not for your specific car, but it could be the issue.

Thanks Nexus. I did remove the pulley, but the tension does not seem to be adjustable, unlike with my old belt tensioner. The tension part is sealed once you remove the pulley, so you cannot access the bearings or whatever. No bolt holes or anything else, other than the one for the pulley. Unless I am supposed to somehow manually spin the tensioner clockwise or counter-clockwise a little??? But there are no alignment markings like on my old one.

Ok, this is what I have learned so far. The idler pulley on my car is fed by the PS pump pulley at 8 o'clock and the crankshaft pulley at 6 o'clock (assuming the idler pulley is in the center of the clock), so the longest distance from the middle of these two feeder pulleys to the farthest point on the idler pulley would be from 7 o'clock pointing at 1 o'clock. So rotating an idler pulley, for example, clockwise towards from 1 o'clock to 2 o'clock would make the distance shorter, hence, easier, for the belt to be installed.

So I compared the old and new belt tensioners. On the old, GM tensioner, the line from the center bolt of the movable tension part to the bolt for the idler pulley is pointing towards 4 o'clock. So when you move the pulley clockwise towards 5 o'clock to put the belt on, the distance becomes super shorter (the shortest distance would be if it were pointing at 7 o'clock when turned clockwise).

But on the new, aftermarket tensioner, the line from the center bolt of the movable tension part to the bolt for the idler pulley is pointing towards 12 o'clock! This means when I turn the idler pulley clockwise to 1 o'clock, the distance actually becomes *longer*, and even harder to put the belt on!! This is unreal!!

There is no way to adjust the movable tension part on this new tensioner, unless I were to pry the over off?? But I unbolted the movable tensioner part from the old GM tensioner, and it appears you can only install it one way, assuming the designs are the same. So there would be no way to adjust this on the new tensioner anyway, so this has to be a design flaw for the aftermarket part. Unless I am reading the mechanism on the old tensioner incorrectly? I can't figure out why the old tensioner does not work, or how exactly it is supposed to work in the first place. I think there needs to be a spring to return the pulley when it reaches the farthest clockwise point, but the spring there is not long enough. The official Chevy shop manual has nothing about rebuilding a belt tensioner.

So it's either live with the design flaw and find a new belt, or get a GM tensioner and try to return the other tensioner to the store, even though it is all dirty now from the installation!

Julie

The numbers on the belts usually mean the length and some other stuff. For example: Belt # 3850 is 85 cm, or 85 mm, or 85 inches length. You have probably already checked:

This has gotten way way too complicated. Is the belt correct? Is the replacement part the same? Can you verify from a junk yard model, photo, or something of what is valid anymore?

Sounds like two simple things. The belt being tieh right one and routed correctly, and a tensioner being correct. hell, you may as well go back to what you had at this rate.

maybe the original problem was misdiagnosed from the start?

Yes, belt is correct. New is the same length as the old one (Dayco), and the old one is the same length as the even older one (Gates)! Placement is the same and matches all diagrams. I have done it numerous times on the old tensioner. The tensioners are different, although this new one is "supposed" to work for my car.

I know! :)

Well, the old tensioner is shot. It no longer holds the tension on the belt. Just pressing the belt causes it to go to the "install" position and the belt becomes loose. I might be able to rebuild it, but I don;t know how, and the manual is silent on the issue. The new tensioner is nice and tight, but the pulley is placed in such a way that you cannot install the belt, and there is no way to adjust it! I blame the aftermarket parts industry for this. :)

Julie

Thanks Paul! I will check this out then.

Julie