Alternator Belt slip trouble

[sodave]

Hello everyone. I have searched the forums and not found an answer to my Q so here I am starting a new topic. I have a 1994 Ford 5.8 EFI mated to a OMC cobra SX outdrive. I have trouble with the alternator belt slipping then failing. I had the trouble last year, using 3 belts in the season. I started this year on a fresh one, which i destroyed last night.

My original mistake was I left the belt slightly loose, using measured deflection as the gauge for tension. Later my mechanic friend told me that when checking alternator belt tension that when you grab the fins on the alternator (behind pulley) that you should not be able to slip the belt at all, & when i do that - the belt lasts longer.

More background - last year I ran the engine & sanded the pulleys to make sure they are clean. The alternator spins free and easy by hand - bearing feels good. The pulleys look to be in alignment. When the belt slips it seems to ride down in to the alt pulley.

What can I do about this? I don't like having to worry about belts every time I go out.

Thanks -Dave

 

[Don S]

Re: Alternator Belt slip trouble

I know you said you sanded the pulleys, but they have to be really smooth and painted or they will keep wearing out belts. A rusty corroded pulley acts just like sand paper on the belts.
If the pulleys are to bad to clean up, they should be replaced.

 

[chiefalen]

Re: Alternator Belt slip trouble

i had a bad alternator that also turned easy with no belt on.i sanded and painted the pulleys.before i did that i went thru belts also.than i went thru another belt and i had a friend on the water watch the alternator while underway and drawing power with the radio and fishfinder on.damn alternator kept freezing and the belt started to smoke.could be a bad alternator and u don't even know it.good luck

 

[Fishermark]

Re: Alternator Belt slip trouble

I'm not that familiar with Fords - so this may or may not help... is that a serpentine belt or a v belt?

If it is a serpentine belt, the tensioner pulley could be wearing out. This happended on my truck engine with a serpentine belt. It looked fine, but apparently the busing inside the upper part of the spring loaded tensioner, (did you follow that? ), wore out and caused a misalignment. Replaced the tensioner and had no more problems.

Just something to check.

 

[sodave]

Re: Alternator Belt slip trouble

Thanks for the ideas. It is a V belt by the way. I'm heading down tonight after work to check & sand the pulleys if needed.

I will let you know how it seems.

 

[Dakota47]

Re: Alternator Belt slip trouble

you really need a dremmel to get it perfect.

 

[sodave]

Re: Alternator Belt slip trouble

I went down last night & the alternator pulley had significant rust & rubber on it. I sanded for a while by hand, then put the new belt on & started the motor. I then carefully put the sandpaper in the open spot of the pulley & "power sanded" the alternator pulley.

I went out for a test run & through all the RPM's it did not squeal once. I will have to wait & see if it holds for the season.

Thanks for the help. if it goes again I'm taking the alt in to get checked.

 

[chiefalen]

Re: Alternator Belt slip trouble

hope that did it for you.good luck and clear sailing.

 

[bekosh]

Re: Alternator Belt slip trouble

i had a bad alternator that also turned easy with no belt on.i sanded and painted the pulleys.before i did that i went thru belts also.than i went thru another belt and i had a friend on the water watch the alternator while underway and drawing power with the radio and fishfinder on.damn alternator kept freezing and the belt started to smoke.could be a bad alternator and u don't even know it.good luck

What chief said. I had the same problem. Alternator tested fine on the bench. Rotated smooth, and ran fine until there was a load on the electrical system. Then the alternator tightened up and the belt would squeal, ultimately eating it thru.
The only thing that finally fixed it was to replace the alternator.