NOOB question. How to tighten 1HDT alternator belt (1 Viewer)

[Lumpskie]

Hey guys,

I am getting some squealing from my alternator belt(s). I see this adjusting mechanism here:

Do I loosen the bolt on the right then tighten the adjusting bolt to increase tension?

Please forgive my noob question. I just want to do it right.

Thanks,

 

[mudgudgeon]

Correct.
Loosen the bolt on the right, but also loosen the bolt that the alternator is mounted with so the alternator can pivot more easily

 

[hj 60]

You might need new belts so to prevent getting the wrong ones try to write down the numbers on them, also good to buy new and keep old as spare.
And getting close to a live alternator better / maybe remove one battery cable to prevent sparks, do you have a fsm for your cruiser?, nice to read/print before wrenching.

Also maybe the tensioner pulley (if you have that) or any pulley bearing might be seizing up so the belt squeeks, just to know.

This is for a HJ60 so maybe not for your 1HDT engine but to get an idea:

 

[Mookies]

Even with that main bolt turning easily, I've found it's tough to get enough tension especially with fresh belts...too easy to round that bolt head or even snap the bolt in the carrier (ask me how I know) A lever between the side of the block and the the alternator works wonders.
I agree with Mudgudgeon that you might as well replace the belts if you don't know the history.

 

[Lumpskie]

Thanks for the feedback, guys. It looks like I should put new alternator belts on my long term list. (with all the snow and water inside my garage from driving, I'd rather do that job in spring!) For now, I can tell that they are really loose. With the engine running I can see them wiggle... especially if I give the engine a rev. One more noob question before I tackle this after work... Do you tighten or loosen the adjusting bolt? (I can't tell if the bracket moves or that small block moves. I guess I can guess and check.)

 

[IanB]

Loosen the bolt in the small block so it doesn't clamp, then tightening the bolt on the bracket should tighten the belts, then tighten the bolt in the small block so it clamps and holds tension.

 

[Lumpskie]

Thanks @IanB . I'll only have a few minutes free after work tonight and getting these details straight in my head is a big help.

 

[Lumpskie]

Belts tightened and they don't seem to squeak! Tomorrow's commute will be the real test.

Thanks guys.

 

[mudgudgeon]

It's probably time to think about getting some replacements.
I've always thought if they have worn to the point of slipping, and you are retensioning them, they're just about on borrowed time.

Cost of replacement vs consequences and inconvenience of a failure?

 

[HillCountryTX]

@Lumpskie , did adjusting the tension on your alternator belts get rid of the squealing? I am about to do this...however, I just got new alternator belts installed on my HDJ81 and it has started to squeal. Upon inspection I noticed that one of the belts is much looser than the other, so I am going to adjust the alternator to adjust the belt tension.

Any helpful tidbits or advice would be appreciated. Did you attack the bottom "pivot" bolt (on the alternator) from below the vehicle, or did you do everything from above (i.e. engine bay)?

Thanks!!

 

[Lumpskie]

@Lumpskie , did adjusting the tension on your alternator belts get rid of the squealing? I am about to do this...however, I just got new alternator belts installed on my HDJ81 and it has started to squeal. Upon inspection I noticed that one of the belts is much looser than the other, so I am going to adjust the alternator to adjust the belt tension.

Any helpful tidbits or advice would be appreciated. Did you attack the bottom "pivot" bolt (on the alternator) from below the vehicle, or did you do everything from above (i.e. engine bay)?

Thanks!!

Yes sir, no more squeaking after adjusting. I was fortunate in that both belts felt pretty similar in tension. If one is much looser than the other, I can see it being tricky to get a tension that would make both belts happy. I did all my work from the top and didn't mess with the pivot bolt. Outcome has been good so far!

 

[IanB]

When you buy new OEM alternator belts from Toyota, they come as a matched pair, so proper tension on 1 of the belts = proper tension on both belts.

 

[HillCountryTX]

I had Gates belts installed (identical belts). I spoke with the mechanic who did the work and he said it could be that one of the belts is "bad" and may need to be replaced. I too found it odd that one belt would be looser than the other when they are supposed to be identical. He thought it would be worth trying to adjust the tension on the alternator to see if that fixes it...

 

[HillCountryTX]

So the plot thickens...I went to check the alternator set bolt/adjustment bolt to and the adjustment bolt is GONE (i.e. missing).

 

[IanB]

Well that's a problem, lol. Are the threads OK? As in, all you need is a new bolt and it should hold tension?

 

[mudgudgeon]

It would be worth checking the part numbers on the belts are the same i.e. same length belts
They should both have the same tension on them, if you can feel a difference, they aren't matched

 

[HillCountryTX]

@IanB and @mudgudgeon , yes, it blew my mind The threads appear ok on the alternator belt tension set "block"...it's just the adjusting bolt that is gone. The belts have the same Gates model # and appear to be identical in every respect (they are on the truck, so I can't see about relative length/circumference of the two 'identical' belts). Right now the alternator is held by the set block and the bottom pivot bolt.

My plan is to first loosen the pivot bolt on the bottom of the alternator, then loosen the set block bolt and use some leverage (instead of the adjusting bolt/screw) against the A/C compressor and hopefully get more appropriate tension on the alternator belts so they are equally tensioned and don't squeal. My guess is the adjustment bolt/screw simply worked its way out of the threaded set "block"...perhaps it didn't have enough tension on it when the set block was tightened? Who knows...

 

[Lumpskie]

If I remember right, if you loosen the block bolt, adjust with the adjusting bolt (left in my picture) and retighten the block bolt when you're done, your adjusting bolt is still loose and could fall out. After tightening the block bolt, you need to remember to tighten the adjusting bolt as well.

Long winded way of saying, I can see how that can happen. Once you get a new adjusting bolt, be sure to tighten it and you should be good.

 

[HillCountryTX]

Thanks @Lumpskie ! I can see how that could happen. I've been told that the adjustment bolt is an M8x1.25 and it's around 3-1/4inches in length.

I believe you have to loosen the "pivot" bolt at the bottom of the alternator to allow the alternator to actually move though, correct?

 

[Lumpskie]

Thanks @Lumpskie ! I can see how that could happen. I've been told that the adjustment bolt is an M8x1.25 and it's around 3-1/4inches in length.

I believe you have to loosen the "pivot" bolt at the bottom of the alternator to allow the alternator to actually move though, correct?

You are supposed to. But, I didn't have to the last time I adjusted. Being the pivot, it would have to be really tight to keep assembly from moving for adjustment.