Belt Tensioner Question

[george_01]

Want to replace pully on belt tensioner. ALLDATA shows a sqare hole for 1/2 in breaker bar to relieve tension. Mine has no such hole. ALLDATA says to turn counter clockwise to relieve tension. Looking at it ... it appears that if you would turn it clockwise it would lift up from belt? One post I saw in the search section said the newer tensioners had a hole for a 3/8 socket to relieve tension. I see no such hole? Can any one tell me what is the right way to do this....before this novice diesel mech. turns a $20.00 job into a major catastrophy?!?!?

[TJ Moose]

Mine has no 1/2" square hole for a drive either - I just put (I think its a) 18mm socket on my 1/2" breaker bar. Go CW to lift pulley upwards off belt. If removing idler - you can lift idler up off belt first to get belt out of the way, then lower it and go CCW to loosen idler nut.

[TJ Moose]

Ooops - sorry - one more detail (fingers going faster than brain) that 18mm socket goes on bolt in middle of idler pulley.

[george_01]

Mine has no 1/2" square hole for a drive either - I just put (I think its a) 18mm socket on my 1/2" breaker bar. Go CW to lift pulley upwards off belt. If removing idler - you can lift idler up off belt first to get belt out of the way, then lower it and go CCW to loosen idler nut. This may be a stupid question.....but... to determine Counter Clockwise....would that be sitting in the drivers seat or standing in front of truck looking back? And the only place to put the breaker bar socket is on the bolt that goes all the way through. Is that where to put breaker bar? There is no other place on the whole unit to put a socket onto except the pully it self? Thanks for your help!

[GMC Hauler]

Mine on my 96 is similar as you describe it. It turns counterclockwise to loosen. I carry a spare 1/2" drive breaker bar to operate the tensioner (which has the square head). Maybe it's for another year?

[george_01]

This may be a stupid question.....but... to determine Counter Clockwise....would that be sitting in the drivers seat or standing in front of truck looking to back? Thanks for your help!

[TJ Moose]

Yep, George 01 - the nut (or bolt - heck, I can't remember sitting at my desk at work) in the middle of the pulley. And CW or CCW is from standing in front of your rig looking into the engine compartment (like you're standing in front of your rig looking to the back of it), straight on at your pulley. It does take a long bar (like 12 to 18 inches)to make it easier. I first tried doing this with a regular 1/2 inch ratchet drive crafstman handle - and the spring tension was a real fight. The longer bar made it easier.

[george_01]

Thanks alot... you are a great help....made it understandable...going to tackle it right after dinner.........THANKS!!!!!

[george_01]

Done everything as explained. Belt tensioner lifted up counter clockwise as it is supposed to. However it does not lift up enough to clear the belt or take all the pressure off belt. Not enough clearance. What else do I have to loosen or take off to get belt off? Thanks again Guys for your patience.

[TJ Moose]

Well - that's one of those things that make ya go "hmmmm." I've not had that problem. I'd check a few things -
First - make sure you've pulled the idler up (using the wrench method) as far as it'll go. That's one stiff spring on it.
Second - if you weren't the one to do belt service on this previously, you might check to make sure you have the right belt. Maybe someone somewhere along the line either got the wrong belt, or put on a short belt. (Don't know why that's be - but people are funny, and I've seen some mighty strange things under the hood of cars that someone has touched before I have....) That tensioner should easily lift an inch or so, and slipping the belt off the pulleys should be a piece'o'cake.
If you find you have a short belt - you might buy the right one, and just take a knife to the old one.
OR - conversely - maybe your whole tensioner assembly (as opposed to just a pulley problem) is jammed up - which may be why you're doing this in the fist place. In that case - maybe same solution - to get at the tensioner, hold as much tension off the belt as you can, cut the old belt and slip it off - change out whatever on the idler pulley/tensioner assembly isn't functioning properly, then get your new belt wound around all the pulleys in the correct manner, and then put your wrench back on the idler pulley bolt to lift the tensioner up, slide the belt under, and you should be sucessful.
I can't impagine why you don't have enough clearance to get off your belt. I can only think of a few things that would affect it -short belt, hung up tensioner assembly that won't seing far enough, or perhaps there is a component with with a non-stock size pulley (easiest to get a different pulley the alternator?)but I'd first start again with using a little more force on the pulley tensioner to make sure its swinging all the way out of the way, then start going through the other possibilities.
Good luck George - you got me scratching my head on this one.......

[TJ Moose]

Oh - and now you have me thinking (dangerous when that happens) if all the other things check out - I suppose you could always ask your parts place to get you a slightly longer belt - just enoughg to route and slip under the tensioner. That'd be my last choice - because if everything else is right, you shouldn't be having this problem. But its just one more solution to keep in your bag of fixes. More than one way to skin a kitty cat......
(Legal dsicalimer - figure of speech only - no animals were injured during the course of this repair.....) :)

[TJ Moose]

One more thing - maybe the pulley on the tensioner is the wrong size if someone changed that in the past. That'd be the easiest hard component to install as a wrong part.

[BigMikeO]

I have a 95 also and I could not get my tensioner to move enough when I was replacing my alternator. But, what I was able to do was remove the nuts holding on the Alternator, the bottom bolt holding it on is a lot longer than the others so I Slowly pulled, tapped, yanked the alternator towards the front of the truck and I was able to tilt it towards the drivers side fender and then down so it was hanging to release the tension. I did the oposite to put everything back together.

Oh, if you do this make sure you unplug your Alternator first :rolleyes:

Mike.

[rjwest]

Sounds like a lot of aftermarket stuff that almost fits..

Take out the pully bolt to get belt to clear pully. Need to hold tensinor at stop and lossen atsame time... Need extra hands WATCH the fingers.

My experience, BUY GM Tensioner/pully assembly, and GM belt. Went through many belts with AFM cr*p

If with GM parts and still a problem than one of the other pullys are non standard , Also cheap belts will strech and fray...

[TJ Moose]

George - I'm with RJWest - if you don't want to start by cutting your belt off, swing your tensioner as far as you can, block it with something solid, and unbolt the pulley. One bolt, easy to get to on something that is far less critical (at least less involved) to vehicle operation than an alternator. Tell me what you find - you got me curious now.....

[george_01]

Well guys all this started because of a noise under the hood. Sounded like something rattling....got worse as days went on and could't see or feel anything loose. Guy at the auto parts store listened and thought it might be the tensioner because it had a little play in it. Not much at all (commom fail item he said). Now the rest of the story..... You guys all had good ideas. This 95 truck Standing in front looking to back the tensioner turns -Clock Wise- to release the tension. The 18 mil socket on the pully nut with a small cheater bar worked great. Once the tenioner was lifted I had pleanty of clearance to remove the belt quite easily by myself. I then checkeked all the auxiliaries, none seemed bad, the A/C compressor has just a tiny amount of play....not much at all. I started the motor with the belt off and had no noise.....This pusseled me. OPP'S there is one pully I didn't check. The crank shaft pully. I checked it and it wobbled in my hand. The rubber in that pully that holds everything tight is cracked, hard and brittle. Can't emagine why the truck only has 285000 miles on it. (Just being facious.) Any way...it only has four bolts holding it. Took it off. Parts stores don't carry it. Going to my local GM dealer in just a few minutes to order one. I'll let you know when I'm done. Thanks again fellows!! This novice couldn't do it with out "yall"......

[TJ Moose]

Ahhh - the old "falling apart harmonic balancer" trick. Nice detective work. Glad to be of help.

[DmaxMaverick]

Good find. That problem is more common than generally thought. Problem is, that part is so danged expensive for what it is. For the best price, try www.gmpartsdirect.com (http://www.gmpartsdirect.com) . The S&H is a little high, but much better than it used to be. Be sure to email them with your vin to ensure you get the correct part, and they will respond quickly. The online catalog is not always accurate, and can be difficult to navigate. Their price will be near or below 1/2 of GM list price.

The pulley and balancer have essentially the same rubber in them. I would strongly suggest the balancer be replaced now, while you are in the neighborhood. If the rubber in the balancer has failed, noises will continue, until you hear the noise of a broken crank.

[tom.mcinerney]

Just want to 'second' DMaxMav on the new crank HarmonicBalancer to save the crank while you're there.
Also to echo another post above--I originally intended to replace only the idler pulley on the tensioner, but was not able to find one. So i renewed the tensioner, OEM new. Turns out it was a real good move, as the new tensioner only applied maybe 1/4-1/8 the tension of the old, which had developed a sort of ratcheting-tighter mode (?). The clutch on my AC compressor was machining itself to death. So the tensioner spring should be stiff, but the arm should rock freely. I had to exert a lot of effort on a decent breaker bar to release my old one.

[george_01]

Replaced pully. Cost $190.00 total at local GM dealer. Ordered friday got here monday put on today. He says that is cost to him total. Sounds reasonable. Internet companies wanted $166.00 Plus tax & shiping. Plus 7 to 14 day wait time. Its a good idea to change the harmonic balancer as suggested. However.... I checked it with a pry bar and hammer and could see some of the rubber and it seemed OK. Budget being as it is I didn't replace it. Put everything back together. Sounds good no rattle at all. Getting ready to take a test drive. There was a couple of small cracks in belt. Going to change it in a few days. Now that I have done this job with all of you guys help. The changing of the belt...I guess wont take but a good half an hour. THANKS GUYS YOU ARE ALL A GREAT HELP!!!!! Would have been a night mare and very costly without YOU ALL!!!!!

[Bigg R]

If the bearing is sqeaking and the tensioner seems to still work properly,you can take the tensioner pulley off and read the bearing part number,it is a standard sealed bearing readily available at most part stores and cost about $3.00 and some change to fix! Just F.Y.I.

BIGG R

[David_Jennings]

Take a good close look at your tensioner before you put a socket on the pulley bolt. I just went through this on my 99 and found the square insert hidden behind the sousaphone thingy that comes off the Turbo. I stripped the bolt on my idler.