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View Full Version : FJ40 How to get fan belt straight


RicardoJM
09-13-2008, 06:14 PM
A couple of weeks ago I put in a new alternator and fan belt. The fan belt failed. I looked at the belt and it appears to have worn on one edge pretty heavily prior to failing.

I've got a new belt to put in there and the pulleys for the water pump and crank case are lined up but the alternator pulley is off (closer to the firewall) from the others. I believe this is what caused the premature demise of the belt.

How does one adjust the position of the alternator pulley to get it back in alignment. Do I remove the pulley from the alternator and put some spacer in there? Do I put a spacer between the alternator mounting arm and the water pump. The bottom connection for the alternator is fixed between two arms and there does not appear to be any adjustment there.

treerootCO
09-13-2008, 06:21 PM
Probably the wrong water pump/pulley if I had to guess. Is everything under your hood stock? There isn't an adjustment that I am aware of.

The belt fell off and now your ham radio is connected to a circuit that has constant power?

RicardoJM
09-13-2008, 06:41 PM
Is everything under your hood stock?

The belt fell off and now your ham radio is connected to a circuit that has constant power?

I believe everything under my hood is stock.

The belt did no fall off, the belt came apart.

I'll edit my original post to clear things up a bit:o. A couple of weeks ago I put in a new alternator and replaced the fan belt. After just a couple of weeks the fan belt came apart. When I looked at the old fan belt is looked like it had worn unevenly before it failed. I have a new fan belt on now, and when I look close it is not aligned straight up and down.

kvanoort
09-13-2008, 08:22 PM
If your alternator is located on the drivers side, you can add a spacer or a couple washer to move the alternator bracket out where it attaches at the waterpump. That should get everything lined up. I have a spacer if you want it.

Kent

RicardoJM
09-13-2008, 08:52 PM
Kent, I'll give the washers a go. I'm also wondering if it is possible I tightened the belt too much.

How do others check to see if the belt is too tight, too loose or just right?

Shark Bait
09-13-2008, 08:56 PM
Do you have a FSM, Ricardo? Once you tension the belt , when you push on it, it should only go in less than 1". :)

RicardoJM
09-13-2008, 09:11 PM
I forgot to consult my manual. There is absolutely no play at all, perhaps I do have the belt too tight.

subzali
09-14-2008, 07:39 AM
The pulleys should be in alignment. If they aren't then you have to figure out the reason why they aren't. I would be surprised if from the factory Toyota didn't have them dern close ;).

If the belt is too tight it can also cause too much side force on the shaft/bearings of the alternator and kill your alternator prematurely.

RicardoJM
09-14-2008, 12:42 PM
you can add a spacer or a couple washer to move the alternator bracket out where it attaches at the waterpump. Kent

Kent thanks for the tip, I added a few washers to the spacer and everything lines up very nicely now. I also did not pull the belt so tight. Looks like everything is much better now.

Rzeppa
09-14-2008, 12:54 PM
Looks like the other posts got you straightened out. Sounds like you had 2 issues - the alternator isn't quite right for the application (kinda sorta fits but makes the pulley too far forward or rearward), plus the belt was too tight. If the misalignment isn't too bad (less than ~.1" or so) you can shim it with washers as you have done successfully.

A too-tight belt will cause the water pump and alternator bushings to wear prematurely even when it's lined up right with all 3 pulleys. You always want some deflection - I usually go 1-2" or so.