Serpentine belt issue, 95 D1

[Reddisco1]

Has anyone ever encountered a serpentine belt start to slip off the AC and crank pulley? This happens to me after several thousand miles. It slips off about 1/4 of an inch. I re-install it, several thousand miles later it start to slip off again. All the pulleys seem to be straight and aligned correctly. Could the tensioner pulley be causing this?

Thanks
C

 

[R_Lefebvre]

Something must be out of alignment to do that. Could be any of the pulleys, or could be the tensioner pivot. How old is the belt? Could be some crazy thing like broken fabric on one side of the belt but I doubt it.

 

[Reddisco1]

Something must be out of alignment to do that. Could be any of the pulleys, or could be the tensioner pivot. How old is the belt? Could be some crazy thing like broken fabric on one side of the belt but I doubt it.

Thanks for your reply, it's done it with 3 new belts. First time I noticed it, a couple of years ago, I replaced the belt, got one from BP. that one ended up getting torn up, I replaced it, several thousand miles later the same issue. I replaced that belt thinking is was just a bad belt. Several thousand miles same thing. All pulleys look like they line up correctly. I'm thinking it's got be the tensensor pulley. I'm going to replace that soon, see if that resolves the issue.

Thanks for your help

C

 

[WILL.TILLERY]

Can you take a pic of your alternator and post it?

 

[agbuckle98]

I'll bet you are missing the engine lifting bracket behind the PS pump.

 

[Reddisco1]

Can you take a pic of your alternator and post it?

Here you go Will.

http://claudspics.smugmug.com/gallery/7443707_Ywsp4#480041044_2BBtK


Thanks for your time
Claudio

 

[Reddisco1]

I'll bet you are missing the engine lifting bracket behind the PS pump.

I'll check it out when I get back home.

Thanks
C

 

[They call me Pete]

Is it on right ? This is speaking from experience

 

[Reddisco1]

Is it on right ? This is speaking from experience

Yeah, according to the illustration in my shop manual, it?s on right. It is perfectly seated on the all the pulleys as well.

Thanks
C

 

[robertf]

have you replaced the alternator?

I'm thinking you've got a 96+ alternator pulley and a 94/95 serpentine belt. It kind of works for a while, then slips off and the process repeats.

 

[Reddisco1]

have you replaced the alternator? I'm thinking you've got a 96+ alternator pulley and a 94/95 serpentine belt. It kind of works for a while, then slips off and the process repeats.

Speaking of the alternator??.When Will asked me for some alternator pics , I got to thinking, maybe it has something to to with the altenator. I replaced the alternator 3 years. According to my log, the belt issue started shortly afterwards. The alternator came with the same size pulley, I matched them up. Also, I don?t think it?s possible to install a 96-99 alternator on a 94-95, is it??? I know the pulleys are a different size.


Thanks
Claudio

 

[PeterTh]

It is for sure the tensioner pulley. It is a well known problem/phenomenon that it is getting out of alignment with age, when the spring gets tired and I am sure it must have been discussed in this forum several times if you search for it. One quick fix besides getting a new tensioner is to put something behind it to straighten it up (thin sheet metal or similar). I don?t remember if it need to be on the top or the bottom of the pulley as it was several years ago I did this on my truck. Has been ok since.

Peter

 

[robertf]

Speaking of the alternator…….When Will asked me for some alternator pics , I got to thinking, maybe it has something to to with the altenator. I replaced the alternator 3 years. According to my log, the belt issue started shortly afterwards. The alternator came with the same size pulley, I matched them up. Also, I don’t think it’s possible to install a 96-99 alternator on a 94-95, is it??? I know the pulleys are a different size.


Thanks
Claudio

my 95 has a 96+ alt and it threw the belt. swapped belts and it was fine. As far as I can tell the only differences are the pulley OD and the + terminal diameter, and the terminal might just be manufacturer differences.

 

[R_Lefebvre]

It is for sure the tensioner pulley. It is a well known problem/phenomenon that it is getting out of alignment with age, when the spring gets tired and I am sure it must have been discussed in this forum several times if you search for it. One quick fix besides getting a new tensioner is to put something behind it to straighten it up (thin sheet metal or similar). I don?t remember if it need to be on the top or the bottom of the pulley as it was several years ago I did this on my truck. Has been ok since.

Peter

It's probably not the tensioner pulley per-say, it's really the tensioner pivot. The bushing wears and they pitch over, which also results in the pulley pitching over, but the pulley itself is not the root cause.

This is a very well known failure mode, and it's pretty one of the main things we tested for on durability rigs. How long could the tensioner go before it pitches over too far.

The bushings wear unevenly and pitch over because the centre of the force through the bushing is not centered on the bushing.

 

[Reddisco1]

I'll bet you are missing the engine lifting bracket behind the PS pump.

A missing bracket behind the PS pump would certainly cause the pulley alignment to be off. That?s not the case with mine, it?s there, thanks though!

Claudio

 

[Reddisco1]

my 95 has a 96+ alt and it threw the belt. swapped belts and it was fine. As far as I can tell the only differences are the pulley OD and the + terminal diameter, and the terminal might just be manufacturer differences.

I just confirmed that my alternator is for a 95.

Thanks
Claudio

 

[Reddisco1]

It's probably not the tensioner pulley per-say, it's really the tensioner pivot. The bushing wears and they pitch over, which also results in the pulley pitching over, but the pulley itself is not the root cause.

This is a very well known failure mode, and it's pretty one of the main things we tested for on durability rigs. How long could the tensioner go before it pitches over too far.

The bushings wear unevenly and pitch over because the centre of the force through the bushing is not centered on the bushing.

This makes the most sense to me. I?ll be replacing the tensioner this weekend. I think it?s pass due, it?s got 180,000 miles on it.

I thank everyone for their input.

Cheers
Claudio