Belt Jumping XJ 4.0 1991

Hi all, not the one to typically ask this sort of stupid question if it involves simple mechanics, but here goes.

Had this xj for a couple months, stripped it out, drove it a bit, put a new belt on it as the other one was starting to crack.

Today I noticed the belt was slipped of a couple teeth of the crank snout gear.

Figured it was the a/c compressor bypass, but I measured it and shimmed it to be perfectly in line.

Reset belt, tightened it, tightened P/S pump down good, drove it around the block nice and easy, got back, belt slipped/jumped first 2-3 grooves again.

Wtf? What'd my dumb arse go mess up?

Last pic is of the shimmed/aligned ac bypass.



https://www.facebook.com/photo.php?...325921.-2207520000.1479604210.&type=3&theater

https://www.facebook.com/photo.php?...325921.-2207520000.1479604210.&type=3&theater

Check the harmonic balancer.

Jeep Driver said:

Check the harmonic balancer.

Click to expand...

This.

And count the number of grooves in the belt. Don't assume the number is correct. I've seen mismatched pulley and belt before. Sometimes it is the belt, sometimes the alternator pulley. But most likely a wobble in the harmonic balancer.

8Mud said:

This.

And count the number of grooves in the belt. Don't assume the number is correct. I've seen mismatched pulley and belt before. Sometimes it is the belt, sometimes the alternator pulley. But most likely a wobble in the harmonic balancer.

Click to expand...

Thanks, was under it again today and grooves are right. Also ran it and it does not appear to wobble at all, nor vibrate when i had a finger on the side of it. Rubber looks good.

Can the whole assembly walk forward a 1/4" or should I just try a new $60 balancer and see what happens?

SneakyRussians said:

Thanks, was under it again today and grooves are right. Also ran it and it does not appear to wobble at all, nor vibrate when i had a finger on the side of it. Rubber looks good.

Can the whole assembly walk forward a 1/4" or should I just try a new $60 balancer and see what happens?

Click to expand...

Yes.

hey well i got a new balancer, the old one still looks perfectly fine but i put in a new seal and got it on and now the belt is riding perfect. thanks for the help guys. $60 and harbor freight later its good to go.