Rear axle "alignment" and rear tire wear

[pmou]

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.

[Mmusicman]

..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.

[dcsleeper]

does your rear have 3" perches or is that assumed by a post from a member with the old FG leafs?

[pmou]

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.

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:

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.

[MI_Ghost]

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

[pmou]

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.

[pmou]

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.

[pmou]

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?

[pmou]

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.

[pmou]

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.

[pmou]

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.

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

[WoodButcher]

Did the bushing slide on the sleeve?

[pmou]

Did the bushing slide on the sleeve?

That is certainly what it looks like to me, although i thought that shouldn't really be possible as I thought they would be bonded to each other in some way? And the bushing should occupy the full width (3") of the opening?

[pmou]

U bolts arrived, look good to me. 9/16 x 18tpi

and their quality control is top notch

going to be at a JY this weekend to look into grabbing plates from a dodge truck, see if these can end up being used with that.

[pmou]

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.