Vibrating fan belt.

[on-ramp]

Just reinstalled everything after some alternater work. I got the alternator in the same position it was before i took it out.

and placed the 3 shims inside, 3 shims outside, same as before.
but now, the belt is vibrating only on one side (the left side) at idle speed.

what gives?


thanks.

[bell]

sounds like it's a little loose.......belts can stretch, or maybe the alternator housing is sitting in it's "perch" better (did you clean anything up?)
reshim it so it's tighter IMO

[K. Roman]

Is your alternator tightened down on the fan evenly?

[on-ramp]

yeah, it's tightened down evenly.

and i did clean out some dirt that's been sitting after all these years.

i currently have 3 shims inside/3 outside....how do i make the belt tighter?

[Jim Sims]

Move another shim to the outside.

[Gunter]

Is it a new belt? Feel how tight it is by pressing the belt with your thumb halfway between the two pulleys, the belt should move in by about half the thickness of your thumb. A rough estimate. Too tight means a load on the Alt/Fan bearings. Too loose could be possible slipping of the belt when Alt output is needed for A/C, lights, wipers,etc. Make sure that the pulley halves align when tightening the nut. Don't just stick something into the fan to hold it, use the proper special wrench to counter-hold the fan. Less shims on the inside means tighter belt.

[on-ramp]

no, it's an old belt.

but i found out the problem, the 3 outer shims were not sitting properly over the shaft....they had fallen off and as i was tightening the nut, they got crushed and distorted, so the fan belt was not as tight as it should've been.

I actually had to Scoth tape the 3 outer shims together (after banging on them with a hammer to flatten them) to get them to stay on there properly while i secured the nut. did the trick. no more vibration. everything is back to normal (for now).

appreciate your input

[bell]

glad you solved it, over time that may have cause problems

[john_colasante]

Originally posted by on-ramp
I actually had to Scoth tape the 3 outer shims together (after banging on them with a hammer to flatten them) to get them to stay on there properly while i secured the nut.

Anyone who hasn't squashed those shims and had to hammer them flat is lying or has never changed their fan belt.

[on-ramp]

Originally posted by bell
glad you solved it, over time that may have cause problems

thanks...i'm usually very picky about little things that dont look quite right on my car....like a vibrating belt.
sloppy work is recipe for disaster.