[frank2w87]

I have the 80 amp alternator in my 1972 T/A. It is flipping belts and the pulley screams at low rpms. I believe the bearing is bad. Can this bearing be replaced and any idea who would do this. One guy told me the pulley is not designed to have the bearing replaced. I have not seen a replacement pulley in the catalogs. Thanks

[455hota]

Your friend is correct, the pulley bearing is not designed to be replaced. On my 71 TA, I took the pulley to a competent machine shop and had them remove the old one and install a new one. Once I had the old one out I was able to get dimensions off it to select a replacement one. Make sure you use a sealed bearing, since you will not be able to lube it once it is in place. Once I did this I had no more problems with belts coming off.

...Steve

[frank2w87]

Thanks, Steve. Nothing is ever easy...

[RAM AIR 1967]

It is the same bearing that is in the altenator.

[455hota]

No, it is a larger bearing than the alternator.

PS do not try to rrun the car with out the idler pulley. I tried with out the correct setup and the resulting amount of side load on the waterpump caused me to wear out two waterpumps after only 50 miles on each waterpump. It took me two waterpumps to realize it was me not the waterpumps. That is when I found out that Pontiac engineers install things for a good reason.....

...Steve

[njsteve]

He's wrong about the non-replaceability. My grandmother's 75 Firebird (original owner family heirloom) has the same 80 amp setup. It screamed under acceleration no matter what the adjustment was on the belt. The bearing went and I unbolted the pulley from the bracket, pressed out the bearing and went to my local Napa auto parts store and they matched up the part number on the original bearing. (unfortunately the part number is on the side that faces the inside of the pulley) They even had it in stock. It presses back in very easily. BTW this setup screaches even with a new bearing. It has more to do with the harmonic vibration that the long section of unsupported belt creates than any bad bearings. But the bearings do get noisy after 30+ years of use.

[frank2w87]

Thanks Steve - I'll try that. I was going to send it to Paul at Ram Air Restorations. He said he did one a few years ago and it would be about $100. But if I can do it locally I will save $ and time.

[njsteve]

I think I paid about $8 for the bearing and was able to press it back in with a bench vice and a socket. I never even had to use the hydraulic press.

[schneidsd455]

Steve,

Does the bearing press out toward the front or back of the pulley? To me it looks like it presses out toward the back, but I don't want to try without knowing for sure.

Thanks,
Jeff

[njsteve]

It only presses out one way, so if it looks like the back, that must be it. Good luck on your project.

[njsteve]

I dug through my old parts and found the old idler pulley bearing. It is part number 6203 RS. Have your local autoparts store cross reference it and you're on easy street.

[schneidsd455]

One way, yes, but which way did it press out? Just want to make sure that I'm seeing it correctly.

[engineer]

look at it and see which side has a lip to prevent removal.

[Don57]

Has anybody tried to locate an aftermarket V-belt idler pulley? Would they handle the RPM? How about those Ford pulleys? My idler pulley squeals as well.

[zbuickman]

When you change that bearing dont forget the loctite green!!!!!!! This is the press fit bearing correct??? parts store may have to order the green loctite but, it for press fit applications

[njsteve]

I now see what you mean. I guess there were two different pulley designs. Anyone have an extra later model pulley?

Here's what I just posted in my thread: http://forums.maxperformanceinc.com/...t=idler+pulley

I was tracking down a grumbling sound in the belts and it turns out that the bearing in the idler pulley on the 80 amp alternator setup is going. The bearing is actually loose in the pulley.

The 1972 pulley is different than the same set up on my 75 Firebird. The 1975 has a replaceable bearing but the 1972 is sealed in and doesn't look like there's any way to remove it.

Anyone run into this before? I replaced the bearing in the 1975 pulley and it was the same bearing as in an alternator rebuild kit.




and here is the removeable bearing in the 1975 pulley. It has a snap ring that keeps it in place.

[455hota]

Yes the 72 pulley in your first pic is exactly what I had to deal with on my 1971. Like I said I took it to my local (competent) machine shop, (hard to find some times). I showed them the issue, and they were able to remove the old bearing. We then matched up a suitable replacement one, and they then pressed it back in and re-swagged over the lip. It cost me over $100.00 but at the time I had no option. It worked like a charm! no more noise!

['ol Pinion head]

Steve, Have several 80 amp idler set-ups I'll ck my tub & see what I have extra.

[Pepi]

'ol Pinion head, I have been looking for one of those pulleys also if you have more than one.

[RicksGTO]

Steve, I had the same problem on my '72, ended up sending it to Ron at Potomac as he had a source to have them pressed out and a new bearing knurled in place. Runs quiet so far on mine.