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Rear axle "alignment" and rear tire wear

12K views 94 replies 10 participants last post by  pmou 
#1 ·
OK so, got something weird going on with the rear end.. gonna try to explain as best as possible (and please be patient with my ignorance, I have not owned a solid axle vehicle before):

currently, i have the JOR kit installed with new shackles and hangers. I verified today that they are all in the correct orientation.. I will take pics (see next post) for sanity but for this moment let's assume I am not a total space cadet. Also did leaf spring bushings at that time and new shocks. Left the stock leaf springs (hence bushings). This van was in a front PS accident that required a new front body panel and new PS door. Nothing past that that i could see in the immediate area when i bought it. There's definitely something minor in the front rad support & bumper is slightly tweaked (the actual bumper, not mounts, crumple zones, etc). Subframe looked untouched as well as all suspension parts so i thought good.

The van had some real old tires on it, fine with me i was going to put bigger ones anyway. I noticed right away that the rear DS rear tire had heavy camber wear on the outside knobs. figured the van had just never been aligned at all. Installed lift & 30.5x10.5 tires on new rims. When i went to install the shocks, i noticed that the mounts seemed to be off to the PS. Enough so that the DS one would have rubbed the mount if I didn't space it out to the PS at the top mount about 3/4".. which I did just to have the thing be driveable. Thought maybe it had just been sitting and a quick drive around the block everything settles in and we are good. Well, it's still off. The tires are also noticeably sitting in different spots relative to the wheel wells, off to the PS. I did about 900 mi of driving on it over the weekend, was planning to get an alignment after that. Even just in that short amount of time the outside knobs on that driver side tire are wayy worn, like noticeably so and have lost some minor details that no other tire or part of a tire is showing.

Called firestone as that's where I'd usually get an alignment. They said there's no adjustments to be made there, and they will need to do a full inspection before the alignment to figure out what is bent or otherwise off.

Called a shop I usually use for diff and transmission work, they said this wouldn't be anything internal to the axle which is about where they stop. He suggested bent leafs.

Anyone else want to throw something out there? It'll be going to firestone on monday as that's the soonest i could get it over there, but I'd like to have a little better understanding as to what is going on before I hand it off to them.
 
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#78 ·
Hey woodbutcher, appreciate anything you can offer at this point! there's a lot to follow, so no worries--

Some of the photos in this thread should be identified, but --

The wear I am describing and time frame I described for this wear is on a set of tires I put on, and that tire was always in that location.

The previous tires, which were on there before I got the van also had a similar wear on the rear tire in this location (driver's side). Whether this could have come from another location the tire was used in, I can't say. the fact that both tires had this happen in that rear DS spot made me think that was the cause (as well as the axle being off towards the passenger side at least a bit).

Perhaps the front toe could contribute to some weird overall tracking that is causing the wear in the rear? I'm not sure
 
#79 ·
Lets start at that 121K mileage. Any original rubber bushings & pads have had a good life. It is time to order up replacements. The spring pads clearly show that they are collapsing and allowing the axle to move. Note center pin shoved into the lip. I would not be surprised if the spring eye bushings are starting to show signs of tearing also.

The clamshell clamps are simple stamped steel parts. It takes very little effort to stretch and deform them. Upgrading to a proper u-bolt & plate to insure proper clamping force on the springs is recommended.

Also check the front subframe bushings. If the have degraded they will allow the subframe to shift.
I did not notice if you used the pucks on the front lift or just cranked up the torsion bars.

Torqueing to yield on suspension components is a very bad idea. You will never get proper clamping/holding force. If the fastener feels like it is stretching. Throw it out and get new.
 
#80 ·
Hey Ghost -- thanks for your input! I have replaced the subframe bushings when i did the front lift, they were definitely not looking so good at that time. I also replaced the leaf spring eye bushings as a part of the lift as well, used poly inserts.. you are correct again they were looking pretty bad at that point. The rubber spring isolators I thought didn't look terrible, but i will probably replace them at some point here -- some of this is a bit moot as I've done some work in the meantime.

I ended up ordering 22-1195 springs from sdtrucksprings to replace my possibly worn springs. dcsleeper gave the nudge, and they had a black friday sale so i ordered a pair, they arrived a couple weeks ago. Just got them installed this weekend when an upcoming long drive (8hrs, to SLC) lit a fire under my butt. I thought it was a bit odd that they are very different dimensions than the stock springs, mainly the arch height -- I think it's about 2" shorter on the SD springs. Oh well, I actually didn't measure before/after ride height as my driveway is not level at all, i feel like it may have not changed much as it just sits higher in the travel on these.

Anyway, that went pretty smoothly. Had to ditch the rubber inserts, but kept the clamshells. Also had to cut the bottom of the center pins off, they were too long to fit in the cradles. It did not seem to changed the angle that the DS shock is at relative to the axle. At the wheel wells, I think it may have evened things out slightly, but a little hard to say. Guess the tire rub will tell.

PXL_20201226_181419532.jpg


Also, used @mmusicman's socket trick to get the center pin in place -- thanks for sharing that, huge help. I was able to get it close, then when i tightened it halfway i hit the socket with a hammer to shift the leaf ever so slightly before the full tightening. 15mm deep impact was the magic size for me.

PXL_20201226_191228157.jpg


Pins are centered now, I'll probably double check after the big drive (mostly just big highways) to see if they moved.

PXL_20201226_191235864.MP.jpg


PXL_20201226_181447041.jpg


I think I also would like to go to u-bolts / plates now -- mainly to get some insulators in there. I feel like i can notice the ride sounding a bit harsher and noisier in the back with that metal on metal. See how this goes first.

I also noticed that the front DS tire is having what appears toe / camber outer edge wear. Looks like that idler arm was rough and letting that wheel flop around a bit - maybe related to wear on the back as well? Have that replaced now so we will see. May swap tires PS / DS before the drive as well to see if the wear is still present.
 
#81 ·
Since installed, the axle has slipped. Granted, i did go into a ditch at one point when i went off the road in a snowstorm.. but I think I'd like things more solid than they seem to be at this moment.. The DS seems to have not moved but the PS slipped backwards so that the centering pin is resting against the back of the clamshell centering hole.

Guess that means it's time to try out the plate / u-bolt upgrade. I ordered a couple parts from ruffstuff specialties: ubolts -- UB275, and plates (3", to clear the perch) -- 3F-UPLT .. also ordered some isolators/pads -- energy 3.6112G to install at the same time. I'm a little concerned about the clearance of the u-bolts to the "frame" rails in the body, but I'm not sure I have too many other options so going to give it a shot. Should have all the parts and time in the next couple of weeks here.
 
#82 ·
pmou said:
..the PS slipped backwards so that the centering pin is resting against the back of the clamshell centering hole..
This was discussed way back on page 1. The center-pin bolt on mine was installed upside-down (with threads sticking up). I found a perfect sized "centering spacer" solution.. a socket from a cheap 3/8 ratchet set that fit the bolt as well as inside the clamshell opening perfectly. This was also fastened in place so it's permanent. My axle absolutely can no longer "shift" around on the springs, and has worked for me ever since.

Photo from page 1:



The clamshell is a poor design (with issues..especially if you modify anything)
None the less.. the upgraded plate and u-bolts should be the best solution.
 
#84 ·
ohh!! mmusicman -- sorry, i think i originally misunderstood. I did use a socket to align the pins, which i thought was what you were suggesting. I didn't realize you left them in place to hold it all solid. Thats a good solution! I don't think at the moment i have a socket i'd like to sacrifice, and as you've said the U-bolts will be about as solid as i can get, which is sounding pretty good right about now.

dcsleeper said:
does your rear have 3" perches or is that assumed by a post from a member with the old FG leafs?
So my van has steel springs and I would assume the narrower perches as far as these vans go. However, in my measuring it looked like i would still need a 3" plate to be able to clear the perch. It looks like the perch is a bit wider than the 2.5" spring.. i was debating trying a 2.75" wide plate however the perch seems to "flare" a bit as it goes down and i wasn't confident that a narrower plat would allow the bots to actually clear. I am planning to destroy the one non-ubolt side of the perch in order to accomodate the 2x u-bolts. even still, i think 3" will be just wide enough. I intended to order the same items referenced part way down here: https://www.astrosafari.com/viewtopic.php?f=41&t=127346

Here's a few pics of me roughly measuring the width:

PXL_20210120_142947222.MP.jpg


PXL_20210120_142923454.jpg


PXL_20210120_142838178.jpg


You'll have to trust me a little bit that these measurements on the calipers line up with what you are seeing, i couldn't really fit my calipers all the way in to measure with everything still bolted together. Anyway, you can see that 2.5" and likely even 2.75" would be too narrow. I think 2.75" could maybe work with some minor trimming, hard to say. decided to play it safe. Also looking at that pics in that thread i referenced, it doesn't look like they had 1/4" on their 3" plates to spare.
 
#86 ·
MI_Ghost said:
Here is a different approach to doing the U bolts.

Downward Facing Square U-Bolt Option for Rear Springs
https://www.astrosafari.com/viewtopic.php?f=40&t=145188
Dang, i actually like that option a lot better. It's a little more work.. but it doesn't seem like a huge difference really. I had been concerned about the U-bolts hitting the frame..

My order hasn't shipped yet so I'm going to see if I can cancel it. If so, I'm going to start looking into collecting the pieces for this conversion instead.
 
#87 ·
okay, i was able to cancel that order. My housemate will be at a JY in a few days, i'm going to ask him to grab the extra bottom plates from a random van there. I think i'm going to go with the idea shown in there of re-purposing the clamshell top to act as a leaf spring top plate. I had bought different isolators as I thought I was going to be using a flat top plate.. I think it may end up working out better to re-use the rubber isolators that were on the van as they are shaped to the clamshell a bit and were in decent shape. Let you know how it all works out. Given that this is likely now a bit of a longer term thing, I think I'm going to re-set the rear axle to be square and see if I can get it to stick that way for any reasonable amount of time.
 
#88 ·
OK so based looking through that other thread, I've had a hard time tracking down anything that anyone else used for the square U bolts. After some searching I came across these options:

5/8" (grade 8 "equivalent") https://store.uboltsdirect.com/5/8-u-bo ... side-width
1/2" (grade 5 "equivalent") https://store.uboltsdirect.com/1/2-u-bo ... side-width
3/8 (grade 5 "equivalent") https://store.uboltsdirect.com/3/8-u-bo ... side-width

There are some price differences, and the 3/8 is only offered up to 8 5/16" long which may rule that one out. If so, then i would think it would come down mainly to what size holes I would be able to use, and what grade would be acceptable. I am leaning towards 5/8, as they are grade 8 but am also wondering if the little clamps that would form the bottom of this could accept a 5/8" hole. It looks to me like other folks used 1/2" and possibly not even something officially graded. Based on the pictures from dit / sportsboy, i believe a 5/8" hole would be okay in those perches (of course i don't have a bit that big...).

Anyone have any thoughts? or any other sources for this sort of bolt?
 
#89 ·
Okay, actually maybe this will be the determining factor:

https://www.uboltsdirect.com/torque-specs.html

I believe if I'm remembering correctly that the original clamshell torque was around 70 ft/lb -- so I believe i would want to go at least that high if not higher. According to their torque recommendations, that would mean 1/2" would barely make it, and 5/8" would probably be the safe bet.
 
#90 ·
I ended up ordering 9/16 x 3" x 7 1/8" (a little extra long) + their hardware (nuts + washers) for $66 shipped. much cheaper than bolts and plates as well. Still need to obtain the extra brackets from the JY, that may happen this weekend.

I talked with someone on the phone about their product, they seem like a good company. That said, i would strongly recommend paypal payment on their aging website if anyone else buys from them.
 
#91 ·
Just re-positioned the rear axle for the time being -- getting the studs out of those brackets is not for the faint of heart. I would really probably only attempt that again with a plasma cutter or drill press. I may try to grab some brackets off of a Dodge 2500/3500 this weekend -- they are 3" wide. Or i'm just going to hold off on the square ubolts for now.

anyhow, noticed the passenger side leaf bushing looking a bit odd when i was under there -- these are new as of a few weeks probably like 1100mi at most. rear didn't look like that.

PXL_20210203_235548729.jpg


maybe it's nothing, but figured i'd share for armchair consideration.

I re-torqued the bolts to 80ft lb all around, 6ft higher than last time / recommended torque. on the DS where i didn't loosen anything i probably got 1/2-3/4 turn out of it to hit 80ft/lb. we'll see if it's more solid
 
#95 ·
Oh, i also got new tires .. just had to happen the ones i was running were garbage craigslist dried out tires. wow what a difference first of all. the alignment report again said thrust angle at about +0.36deg.. i decided to do some maths last night and i measured the center pins to be 49.5" apart. based on that, i came up with the tan(0.36) * 24.75 is 0.155" or about 5/32" -- so if this alignment is to be trusted, and this is what was causing the wear, to make the thrust angle 0 i would need to scoot the PS wheel forward 5/32" and the DS wheel back 5/32" .. which seems incredibly minor.. i'm almost inclined to think the dynamic nature of highway driving would practically negate a difference that small. anyone else have any thoughts?

edit: now for consideration, you could say the tire is possibly +12" wider at it's widest point from the center pin.. so that would work out to 1/4" at the tire. or for arguments sake, assume 24" wider (per side) -- that would be 0.3".. still seems quite small.
 
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