V-Belt Lengths for AMC360... Fix for squealing PS pump?

[Greg72]

Just dropping this here for anyone who is looking for really basic info on V-belts or for anyone who wants to share their own findings / experiences.

Like a lot of Grand Wagoneers that I've seen/heard mine has a slight PS squeal on acceleration. It's a double-pulley on the PS pump but only one belt is attached (the outer one). Can't really see a configuration that would allow me to use both pulleys unless there is a more elaborate way to route the Alternator / AC Compressor / Waterpump / Crank pulley belts rather than just connecting them all in a big circle....??



Anyway, went on the Gates.com website looking for some basic interchange information that was specific to this vehicle.
The belt that is currently spinning my PS Pump is a #15542 / 11AV1380 belt which looks like about a $5 "Made in Mexico" item.

The specs on it are:
Effective Length: 54.50"
Outside Circumference: 55.32"
Which makes it a match (interchange) to the Gates #7545

Based on the Vehicle Database on their website, the Grand Wagoneer should use the #7535 which is:
Effective Length: 53.51"
Outside Circumference: 54.33"

If I am interpreting this correctly, that seems to indicate that my current belt is about 1" too long for the application and may be contributing to the squealing that I hear...especially if the tensioner is maxed-out and is unable to tighten up the belt any further...

Seemed interesting... and like many of us, I suppose... we can't really trust that what is on the vehicle NOW is actually what is SUPPOSED to be on the vehicle, so it's worth taking a little extra time to confirm the part numbers and double-check things like this.



-G

[tgreese]

Inner pulley is for the air injection pump. Typically hangs below the PS pump.

Have you replaced the belt? Are you trying to turn hugely oversized tires? Should be ok otherwise. Suggest you replace the belt and tension to the factory spec.

[Greg72]

Inner pulley is for the air injection pump.

Ah.... that makes sense. Mine must have come with a bluetooth air pump. Have not seen it anywhere in the engine bay.


-G

[Greg72]

Inner pulley is for the air injection pump. Typically hangs below the PS pump.

Have you replaced the belt? Are you trying to turn hugely oversized tires? Should be ok otherwise. Suggest you replace the belt and tension to the factory spec.

Tgreese,

I did a little research. The Factory Service Manual does not seem to call out the PNs for the belts or show a tensioning procedure(?). I searched the .PDF version for clues but maybe I wasn't using the right keywords to search.

Just got the #7535 belt (1" smaller than what is currently on there) and what I believe to be the "correct" size for this application. Will install it and see if a high-quality belt makes any difference. Will also flush the existing PS fluid to see if it was burnt.

Tires are 31 x 10.50". I hate them but can't seem to find the whitewall tire that I want in stock anywhere. Eventually, it will get back to the stock 235/75-15 size.


-G

[tgreese]

The parts book will have the PNs, not the TSM. There is a 88J parts book on the Tom Collins site that covers '89 IIRC.

Maybe there's no tension spec in the TSM. Not something I've looked for. Does your bracket have the square hole for a 1/2" drive? If so, I'd expect a torque spec in the steering chapter. There may also be a mention of amount of deflection in the text? V-belt tension gauges exist, but I think a line mechanic would use his calibrated forearm.

If the belt fits, it should be fine. It needs to be long enough to install over the pulleys and short enough so it can be adjusted good-and-tight.

[Greg72]

Hmm... I will keep looking on the Tom Collins site. I have a feeling that I'm missing one of the critical manuals from there.

I don't see a square hole on the bracket (presumably for a socket wrench to add prybar-type tension to the pump while tightening)... but with the current belt the adjustment slots DO seem to be fully maxed-out.



Removed old belt and compared to new Gates one, and this new one is definitely shorter. That should put the PS Pump much closer to the center of those adjuster slots than before and may resolve this whole issue.


-G

[tgreese]

Looking at the '82 manual (that's what I have), the belt tensions are clearly stated in pounds. They use a special tool (of course - profit for Jeep Corp) which I expect is the same as belt tension tools you can find online.

Yes, it should be in the middle-ish of the slots. That belt is too long.

If you have a square socket, it will be on the steel bracket part.

PSpumpAdjuster.jpg

[Greg72]

AHA!!!

That photo clears it all up....

Not sure if this was a factory configuration or something creative from a previous owner, but it looks like my adjuster was repurposed to hold the air injection hose bracket instead which camouflaged it from me initially...




Bracket removed to reveal that 1/2" square-drive hole you were referring to...





New belt installed and tensioned with plenty of room now on those adjuster slots for future retensioning when needed...





Thanks a lot for the help and persistence on this one. The squealing is completely gone, and I even got a little fresh black paint on that PS pulley to get some of the "ugly" out of my engine bay...


-G

[tgreese]

Woohoo!

[devildog80]

Suggest you turn your distributor to OEM position on vac advance position. I recently was able to do the same on mine, as it was up in the belts like yours, but initially did not have room by the power steering pump, until I changed with new belts.
Here was my process and pics of before & after.
Yours does run much farther away than mine was, so if you do not want to do this, probably ok where it is. Just plan for sure you will need to replace vac advance, if you ever lose the power steering belt.

**Reset my distributor vac position, as test drive with radiator engine was pinging a bit on hard acceleration, and I could not drop my timing back enough without getting into the power steering belt.
I looked at this last year, but seemed it would not work as PS pump was too close. Maybe new belts or something cleared a little more room as it worked today.
Simple procedure - Set a marker on any part of the cap or plug wires, keeping everything in place just like you run it, then make a second reference point just like the first on the next plug wire. Now loosen the distributor and turn the whole distributor until you line up on the second mark, just one plug away from the first. At this point you will pull your #1 wire off the cap, and move it back to where it was before you turned the distributor.
So to clarify my process, I made my reference point, loosened the distributor and turned it one plug wire counter clockwise, which moved my vac advance down towards the power steering pump. I then took my #1 wire (the actual one going to plug #1) and moved it clockwise to the hole that is now where my #1 used to be. I continued moving one wire at a time clockwise until I was back at my #1.
Can be confusing, but remember, you DO NOT remove the cap, you DO NOT remove the distributor!
All you are doing is turning the distributor by one plug wire distance, then resetting your wires back to the original position they would have been at, when looking down at the cap from above.

Starting position of my vac advance. See how it is under the power steering belt?
20230924_120707 by Scott Weckerly, on Flickr

End position of vac advance after turning one plug wire counter clockwise.
See I marked a #1 with black marker on the cap? The original position of my #1 was the next one to the right, which has the #1 formed on the cap.
20230930_141025 by Scott Weckerly, on Flickr

[Greg72]

You guys are awesome!

I can't believe how much nicer it is to be learning about a completely unfamiliar vehicle with help from a group of friendly and knowledgeable folks...

For the price of a new V-belt and a little time on the internet, the squealing issue was fixed and I ended up revealing the square-hole tensioner that would have taken me forever to find on my own.

That distributor trick seems pretty straightforward and a clever way to gain some extra clearance and margin of safety basically just rotate 45* for each "skip" of the #1 plug wire (8 plugs / 45* each / 360* total)... would it make sense to rotate it 2 positions and maybe get it closer to the driver side valve cover?

On that note: I should probably spend more time building a little photographic database of engine bay pictures. Every time I see a really nice BaT auction vehicle or something that appears to be a 100% survivor-type Wagoneer, seeing the wire routing and position of all of the underhood items would be immensely helpful. I never realized my distributor was "off" from the OEM position.... but after 34 years (and several different owners) guess you really can't assume things are correct and should verify everything.

That's probably the biggest challenge at the moment. I didn't have a good service history on this '89 and everything that I'm digging into (like the recent brake bleeding event) either shows issues or outright neglect. The only way to be sure that things are OK is to do a complete "baseline" service (Coolant flush, Oil Change, Transmission Flush, Transfercase flush, Gear Lube change in both axles)... then start chipping away at other items like coolant thermostat, ball joints, tie rods ends, draglink ends. Eventually, there is enough fresh life-blood everywhere that you can start to build some "trust" in the vehicle and start taking it on longer drives without the constant worry about breakdowns or catastrophic failures.

Thanks again guys, really appreciate all the guidance and helpful tips!


-G