Water pump belt continues to become loose. (1 Viewer)

[fjgdk]

Why does the water pump belt on my 1983 fj60 (stock, not desmogged) continue to come loose after driving 1000 or so miles ? I should note that I installed a new one (not OEM) about 1000 miles ago AND I USE A OTC Belt tension gauge 6673 that is the same type as the one mentioned in the FSM such that I set the recommended "new belt" tension. I am not doing this with some unscientific "I think the belt is set correctly based on my thumb" method.

Could it be the pulleys are not aligned ? If so how do you go about aligning them ?

I hate adjusting this belt because getting the bolt loose on the back of the smog pump to adjust the tension is a beast to get to.

Here is some background:

1) I Purchased 1983 FJ60 from the original owner in 2011 (in Oregon). I had all belts replaced at the original owners dealership (not that going to a dealer matters) about 100 miles after purchase.

2) In the spring of 2017, after about 3000 miles ( I haven't driven the thing much at all), I notice the water temp gauge showing a high temp. Upon inspection, the water pump belt (one that was changed at the dealership) is loose. The belt is also missing a chunk of the underneath part of it.

3) I replaced the water pump and alternator belt with new, albeit non-oem belts. In this process, all three of the ac, alternator and water pump belts were re-tensioned according to FSM spec using the OTC 6673 tension gauge.

4) I drive another 1000 miles or so since (3). Today I warm up the truck for 5 minutes and it starts to get close to overheating. I check the front of the engine and of course the water pump belt is loose (pump not turning). When I hold the belt to the pump and turn it turns. It is just wildly loosened.


So I ask out of desperation, so that I don't have to do this a third time after this fix I will have to undergo, why would the belt keep coming loose ?


Any help is much appreciated !

 

[cps432]

How does the pulley feel on the smog pump? Is it loose? Maybe the hold down bolt on the smog pump is stripped out and isn’t holding it in place well enough to keep the tension. Check all of those things. I can’t imagine your pulleys are out of alignment. Unless something was installed wildly incorrect it just doesn’t make sense.

 

[OSS]

Agreed- if pulleys aren't wobbling, they're fine.

I'd replace that belt with a Toyota belt.
I had one of those Burroughs belt tension gauges too. In the end I didn't like it because it's hard to use reliably with the toothed belt, and can't be used on all of them.

The rule of thumb for belt tension is: if it seems to tight- it is.

If it seems too loose- it is.

If the belt has more than a little vibration while running through the pulley with engine running, it's too loose. You can pretty much eyeball correct belt tension just by watching it run through the pulley.

A belt set on the loose end of acceptable limits is much easier on the bearings of every thing it's powering.

The belt that runs through the waterpump pully should be set so it just barely doesn't squeel (screech) when accelerating with a fully locked fan clutch. (That tension will save the water pump bearing).

 

[Willard]

The rule of thumb for belt tension is: if it seems to tight- it is.

(That tension will save the water pump bearing).

What I was taught eons ago from my old school auto teacher, is if you can move the belt down the same distance as the belt width, then it is correct.
I have used this method for 20 years without an issue. Of course this is only for V-belts cogged or not.

 

[g-man]

Another vote for a worn tensioner bolt or nut. Take them off and inspect the threads of the bolt and nut. there is a lock bolt and and tensioner bolt. If they are not tensioned in the right order it can strip the tensioner bolt.

 

[fjgdk]

When I installed the current belt I took off the smog pump, de-rusted all I could with evapo-rust (various tensioning parts) and re-installed.

I'll have to go re-inspect when the weather improves.

It just seems to me that there is something that is wildly off since the belt seemingly continues to loosen. First with an OEM Toyota belt, then with this aftermarket.

I will probably get a new belt (OEM) when I figure out what this problem is. But I want to find out the cause before going through this mess again.

 

[fjgdk]

Wow, a brand new smog pump runs about $1200 pre-shipping from Japan.

I've been able to get some OEM stuff from Megazip and Amayama that is "out of stock" in the US. I don't think I'll pony up $1200 bucks for a 10psi air pump though.

 

[cps432]

Wow, a brand new smog pump runs about $1200 pre-shipping from Japan.

I've been able to get some OEM stuff from Megazip and Amayama that is "out of stock" in the US. I don't think I'll pony up $1200 bucks for a 10psi air pump though.


View attachment 1879878

Oreilly sells a remanufactured pump for $250.

 

[Gretsch]

Shouldn't you just expect a certain level of belt stretch on new belts? I just replaced mine in the last 2 months and have already re-tensioned several times to compensate for the stretch. I could originally barely get the WP belt on when replacing it with everything full loose. Checked it again and it was loose enough that it needed a re-tension. @beno mentioned to me when I bought the belts that re-tensioning them every 1000 miles or so is to be expected. Not sure if that's in the FSM officially but its something at least I have experienced. I just thought it was a normal part of use. I guess you could mark the location of the tensioner gear and see if it moves when its lose. That would tell you if its belt stretch or moving tensioning gear.

 

[cps432]

Shouldn't you just expect a certain level of belt stretch on new belts? I just replaced mine in the last 2 months and have already re-tensioned several times to compensate for the stretch. I could originally barely get the WP belt on when replacing it with everything full loose. Checked it again and it was loose enough that it needed a re-tension. @beno mentioned to me when I bought the belts that re-tensioning them every 1000 miles or so is to be expected. Not sure if that's in the FSM officially but its something at least I have experienced. I just thought it was a normal part of use. I guess you could mark the location of the tensioner gear and see if it moves when its lose. That would tell you if its belt stretch or moving tensioning gear.

Good thoughts.

 

[fjgdk]

Shouldn't you just expect a certain level of belt stretch on new belts? I just replaced mine in the last 2 months and have already re-tensioned several times to compensate for the stretch. I could originally barely get the WP belt on when replacing it with everything full loose. Checked it again and it was loose enough that it needed a re-tension. @beno mentioned to me when I bought the belts that re-tensioning them every 1000 miles or so is to be expected. Not sure if that's in the FSM officially but its something at least I have experienced. I just thought it was a normal part of use. I guess you could mark the location of the tensioner gear and see if it moves when its lose. That would tell you if its belt stretch or moving tensioning gear.

I don’t know if that is to be expected or not.

What I do know is is that I trust the belt tensioning gauge and tensionspecs more than a guess I could make at whether or not a belt is tensioned properly. Belts are made differently and the same eyeball test cant be used for all. I am assuming the tension was correct and something else is wrong.

 

[RodrigzCrzr]

Did you make sure you have the bushings on the lower bolt to the bracket. If you don’t have that it is probably why it is Loosning.
Just a little play and it can cause havoc.
I was missing mine and once I replaced it with new metal Bushing or spacer it is nice and tight.

 

[cps432]

When you replaced that belt did you change the others? If it is an issue with the belt naturally stretching I would expect the rest of them to also do the same. I just recently changed all my belts and had to re-tension them just a bit after a week or so. I like the idea of putting a mark on the tensioning rod to see if it’s walking itself inward somehow. That’s the only thing I can think of that would cause your problems, other than the belts naturally loosening up once you’ve run them for a while.

Or maybe you have a vibration in your harmonic balancer that’s causing that belt to slip. But I would expect it to throw the others too if it’s bouncing around that much.

 

[cps432]

Did you make sure you have the bushings on the lower bolt to the bracket. If you don’t have that it is probably why it is Loosning.
Just a little play and it can cause havoc.
I was missing mine and once I replaced it with new metal Bushing or spacer it is nice and tight.

THIS! Do check the bushings! I forgot about that...

 

[RodrigzCrzr]

Check the bushings on the air pump.
They are located below the air pump and fit in the bracket holes. The long bolt slides into it and keeps it aligned and tight.

 

[fjgdk]

Did you make sure you have the bushings on the lower bolt to the bracket. If you don’t have that it is probably why it is Loosning.
Just a little play and it can cause havoc.
I was missing mine and once I replaced it with new metal Bushing or spacer it is nice and tight.

Yes I spent quite some time dealing with the bushing (singular).
I couldn't get the old one to fit back in so had to find a new one.
I spent some time ordering various spacers until I found one that was just right from Grainger and the local hardware store. It was the right ID and OD but too long so I had to trim it down to fit in the hole.

Pics from my last belt replacement back on 10/2017

Pic 1 - Spacer/bushing which came out.
Pic 2 - Air pump mounting bracket - the bushing came out of the rear hole.
Pic 3 - Receipt for 2 bushing sizes I ordered from Grainger. Seems the brass one was the one that was a winner.
Pic 4 - My grinder setup to trim down the length of the spacer.
Pic 5 - How I had to hold the spacer to work with the grinder. I purchased a "sacrificial" bolt and nuts to allow for some stabilization and grip on the grinder stand as I cut through the brass spacer.



Pic 1.

Pic 2.

Pic 3.

Pic 4.

Pic 5.

 

[RodrigzCrzr]

Yes I spent quite some time dealing with the bushing (singular).
I couldn't get the old one to fit back in so had to find a new one.
I spent some time ordering various spacers until I found one that was just right from Grainger and the local hardware store. It was the right ID and OD but too long so I had to trim it down to fit in the hole.

Pics from my last belt replacement back on 10/2017

Pic 1 - Spacer/bushing which came out.
Pic 2 - Air pump mounting bracket - the bushing came out of the rear hole.
Pic 3 - Receipt for 2 bushing sizes I ordered from Grainger. Seems the brass one was the one that was a winner.
Pic 4 - My grinder setup to trim down the length of the spacer.
Pic 5 - How I had to hold the spacer to work with the grinder. I purchased a "sacrificial" bolt and nuts to allow for some stabilization and grip on the grinder stand as I cut through the brass spacer.



Pic 1.
View attachment 1880397




Pic 2.
View attachment 1880394



Pic 3.


View attachment 1880400


Pic 4.

View attachment 1880402


Pic 5.

View attachment 1880403

Yup that’s the one!
Ok so you have already done that!
Good
Do you have all the correct tensioners and adjusters on the air pump to tighten it.?
Have you checked your pulley on the water pump and the fan clutch that they are all nice and tight and no wobble?

 

[fjgdk]

When you replaced that belt did you change the others? If it is an issue with the belt naturally stretching I would expect the rest of them to also do the same. I just recently changed all my belts and had to re-tension them just a bit after a week or so. I like the idea of putting a mark on the tensioning rod to see if it’s walking itself inward somehow. That’s the only thing I can think of that would cause your problems, other than the belts naturally loosening up once you’ve run them for a while.

Or maybe you have a vibration in your harmonic balancer that’s causing that belt to slip. But I would expect it to throw the others too if it’s bouncing around that much.

When I did the replacement, here is what I replaced them with:

AC Compressor belt - New
Alternator X PS Pump belt - New
Air pump x Water pump - New

I tensioned them all to the "new belt tension" spec per the FSM with the OTC gauge.

I haven't had any problems with the other belts.

Pardon my stupidity, I have very little knowledge of engines - but do inline engines have harmonic balancers ? I thought those were only for V-configuration engines. Again pardon my lack of understanding.

 

[fjgdk]

Yup that’s the one!
Ok so you have already done that!
Good
Do you have all the correct tensioners and adjusters on the air pump to tighten it.?
Have you checked your pulley on the water pump and the fan clutch that they are all nice and tight and no wobble?

I do believe I got all the correct tensioners and adjusters.

When the problem of a "slipped" belt first happened back in October 2017, I noticed that one part of the tensioning system was missing from the smog pump (I don't remember what). I actually think it was the "bar".

When I realized what was missing, I found it odd that the person who put on the belt six years prior could have done it without that part.

Anyhow, I couldn't find the part new online except out of Japan for big $$. Fortunately there was someone on a local Craigslist who was parting out his FJ60 and so I purchased the set (bar, bolts, washers) of his truck for both the air pump and alternator. I got the alternator adjusting set too because I realized after having looked for the parts new that I couldn't get them new so I wanted to keep the alternator parts on hand just in case.

When I did this, it was my first time accessing the air pump and to do so I removed the PS pump pulley (bolt woodruff etc) to make it easier to access. The alternator / PS belt is working fine it seems.

Something is consistently going on between the water pump and smog pump it seems.


How can I tell if the amount of "play" in the water pump or air pump is too much/too little when I spin them by hand ?

 

[RodrigzCrzr]

Does it look anything like this?