Rear axle squaring

[H20rider]

My ‘68 has a skewed rear axle. Measuring from front hub to rear hub, there is an almost 4” difference. The passenger side rear wheel is noticeably farther back in the wheel well than is the driver’s side wheel. The axle does not line up with underside landmarks on the body. Also, the passenger’s rear wheel is roughly 2” closer to the fen). There are no visible distortion in the frame or evidence of accidents.. I have 2” blocks on the rear leaf springs.

I am wondering about diminishing this discrepancy between sides. I am tempted to loosen the U bolts and rear shocks, Jack the frame up slightly, the support the axle and differential, then try tapping the axle until much closer to perpendicular to the drive shaft. Maybe slide the passenger side leaf spring brackets forward on the leaf springs, then relighted the Ubolts.
Would this plan work, if done with care?

Otherwise, what would work?
If I feasible to adjust at home, I will need to go to some driveline shop.
Thanks in advance.

 

[brewchief]

There is a center pin in the spring to locate the axle so you can't just slide it on the spring.
IIRC the centering pin isn't exactly centered, measure from the front spring eye to the pin and see if both sides are the same, one spring may be reversed.

Sent from my SM-G965U using Tapatalk

 

[SteveL]

A friend had this on his 66 and it was a bent frame. The frame had de-arched causing one leafspring to stretch out an inch or 2 longer than the other.

 

[Broncobowsher]

By chance are the blocks aluminum? They are known to dislocate if not just fall out.
I would start by unbolting the shocks, just so they are out of the way. Next unbolt the axle and pull the blocks out and inspect. I expect the centering pin hole in the block to be blown out.

I've seen enough people have enough issues with aluminum blocks I use only cast iron/steel blocks. Other than some axle wrap issues with a set of sagged out 10-leaf springs I have not had issues with iron blocks.

 

[H20rider]

There is a center pin in the spring to locate the axle so you can't just slide it on the spring.
IIRC the centering pin isn't exactly centered, measure from the front spring eye to the pin and see if both sides are the same, one spring may be reversed.

Sent from my SM-G965U using Tapatalk

I will do that. I have found a few farm fixes so far, so the idea of a reversed leaf is certainly possible. Thanks.

 

[H20rider]

A friend had this on his 66 and it was a bent frame. The frame had de-arched causing one leafspring to stretch out an inch or 2 longer than the other.

I will check their lengths. Good tip! Thank you.

 

[H20rider]

By chance are the blocks aluminum? They are known to dislocate if not just fall out.
I would start by unbolting the shocks, just so they are out of the way. Next unbolt the axle and pull the blocks out and inspect. I expect the centering pin hole in the block to be blown out.

I've seen enough people have enough issues with aluminum blocks I use only cast iron/steel blocks. Other than some axle wrap issues with a set of sagged out 10-leaf springs I have not had issues with iron blocks.

Mine are cast iron. But, I am still going to disassemble and inspect. As I mentioned in another reply, this truck (from Oklahoma) was a ranch/farm vehicle and had some interesting “fixes.” Thanks for the idea!

 

[Doyle]

Also possible the centering pin, bolt has sheared allowing block to slide on spring.

 

[.94 OR]

I guess we are also assuming the front axle bushings are all true and not adding to the measurement problem?

 

[Steve83]

The axle is not mounted to the body, so the body is not where you should be measuring from. Measure from the FRAME to the axle to square the axle up. Then measure from the FRAME to the body to square the body up.

 

[DirtDonk]

And even measuring hub to hub is not necessarily a perfect method. Even a slight, slight turn of the steering will skew the front hubs. So a better method I think would be axle tube to axle tube behind the tires. Just means getting underneath and a little more work, but it should be more accurate than hub to hub.
Even if you were very careful about keeping the front steering straight.

 

[.94 OR]

If it were my question, I think I would initially measure from the front of the radius arm mount below the frame to the front of the rear axle housing. You could also use the same base point to measure to spring pads, spring center pin holes, etc. until you figured out where things are out and by how much. I would question the location of the front axle unless you also take measurements from a fixed location to ensure it is square to the frame as well. All assuming the frame is true.

 

[H20rider]

Okay, I found that there is no center bolt on the passenger side leaf spring….and the block bracket is displaces so far back jag I can just see the very edge of the center hole in the top spring. I could not check the driver side yet ( ran out of time). Tomorrow I am going under for som serious measurements and investigation of the presence or absence of center bolts. It could be sheared off or just not there.

There is a 1/2” difference in axle to ground height between sides(passenger lower), and a 1+” diff in respective ride height at the rear wheels. I need to figure that out as well. But, again…tomorrow I can get more precise on the measurements. Step by step….

 

[DirtDonk]

Okay, I found that there is no center bolt on the passenger side leaf spring….and the block bracket is displaces so far back jag I can just see the very edge of the center hole in the top spring.

Well there ya go! As good as fixed!
Easy to find, and easy enough to make your own center-pin/bolt to replace the old busted one. If you see a nut and threads sticking out of the top of the leaf pack, then the old bolt is still there. Just had the head sheered off is all. Glad you found it!

There is a 1/2” difference in axle to ground height between sides(passenger lower), and a 1+” diff in respective ride height at the rear wheels.

Bottom of axle tube to ground? Only things that set that height are the tires. Either you have unequal tire sizes, or low pressure in one side.
I suppose something in there could be seriously bent, but it's hard to do that and not notice a big wobble as the tire on one side goes up and down as you drive.
Check the pressures all around and measure the tires closely.

Paul

 

[H20rider]

As I say, the measurements were quick and dirty. Even tire inflation could be a factor. Tomorrow I will be more rigorous.

 

[savage]

Hey Paul, could his radius arms be off or a coil spring sagging. I know if you have bronco lean ,it can affect the rear. He said it was a farm truck, could the frame be twisted? Just throwing some ideas out their.

 

[DirtDonk]

Yes to all. Anything is possible at this point. Until some more measurements are taken and a lot more crawling around done, any guess is as good as the next.
My radius arm brackets are not only welded on at different points on my '71, but also at different angles! A friend's project had front coil towers that were almost 3/8" different in height and some other bracket (a rear spring hanger maybe) welded on different than the others.
So yeah, lots of things can add to this. Can you say "stacking tolerances"?

 

[H20rider]

Well, I know that quite often someone comes on and asks for help, gets suggestions, and then does not ever report back on the outcome. So, Just in case this occurs with anyone else, here is what I discovered and di to solve the problem:
I noticed that there seemed to be no anchor pin in the the leaf springs of the passenger side (the side that was dragging).
- I loosened the u bolts on both sides of the axle. On the passenger side, I completely removed them allowing the axle to hang free on that side.
- I loosened the lug nuts of both rear wheels and the jacked the rear end up. I then jacked the axle up so I could remove both rear wheels
- I ir moved the raising block on the passenger side and prayed the leafs with penetrating oil. I then worked the leafs and slide the retainer bracket way up the springs freeing then for easier motion.
-The leafs were misaligned so I wiggled, tapped, and banged the leafs until I was able to line up the anchor pin holes.
-I inserted a threaded automotive bolt through the anchor holes, but made sure the hex head would fit into the raising block.
-the new bolt head was well through the leafs was close to 3” in front of the block depression.
-I used a wooden block and a sledge hammer to coax the passenger side’s axle forward. After some movement, but not enough, I tapped the driver’s side rear axle toward the back. This helped but was still insufficient to square the axles.
- I used a small hand winch between the axle and and my nerf bar to pull the axle end forward.
-once I got it all aligned, I bolted things back together. I know I should have used new u-bolts, but these were new from. Few months ago, andiamplanningon replacing the blocks and old leaf springs soon.

On another note, this was again a case in which professional mechanics shied away from e en trying to repair/adjust. I got everything from, “It just looks crooked”, to, “That’s within tolerance…must have been from the factory, to”you’ll need to replace the whole rear end.” Fortunately, we have this forum that can be so helpful. Thanks everyone who chimed in. I wouldn’t probably wouldn’t have tackled this otherwise.️

 

[DirtDonk]

Thanks for the update and success story!

 

[jamesroney]

Well, I know that quite often someone comes on and asks for help, gets suggestions, and then does not ever report back on the outcome. So, Just in case this occurs with anyone else, here is what I discovered and di to solve the problem:
I noticed that there seemed to be no anchor pin in the the leaf springs of the passenger side (the side that was dragging).
- I loosened the u bolts on both sides of the axle. On the passenger side, I completely removed them allowing the axle to hang free on that side.
- I loosened the lug nuts of both rear wheels and the jacked the rear end up. I then jacked the axle up so I could remove both rear wheels
- I ir moved the raising block on the passenger side and prayed the leafs with penetrating oil. I then worked the leafs and slide the retainer bracket way up the springs freeing then for easier motion.
-The leafs were misaligned so I wiggled, tapped, and banged the leafs until I was able to line up the anchor pin holes.
-I inserted a threaded automotive bolt through the anchor holes, but made sure the hex head would fit into the raising block.
-the new bolt head was well through the leafs was close to 3” in front of the block depression.
-I used a wooden block and a sledge hammer to coax the passenger side’s axle forward. After some movement, but not enough, I tapped the driver’s side rear axle toward the back. This helped but was still insufficient to square the axles.
- I used a small hand winch between the axle and and my nerf bar to pull the axle end forward.
-once I got it all aligned, I bolted things back together. I know I should have used new u-bolts, but these were new from. Few months ago, andiamplanningon replacing the blocks and old leaf springs soon.

On another note, this was again a case in which professional mechanics shied away from e en trying to repair/adjust. I got everything from, “It just looks crooked”, to, “That’s within tolerance…must have been from the factory, to”you’ll need to replace the whole rear end.” Fortunately, we have this forum that can be so helpful. Thanks everyone who chimed in. I wouldn’t probably wouldn’t have tackled this otherwise.️

So I was sitting on the sidelines, watching this thread, and trying to stay quiet. But now you got me.

You claim that the passenger side leaf spring center bolt is missing. BUT, you also claim that the u-bolts are "new from. few months ago"

OK, what's the story? Who installed the lift blocks, and where is the old center bolt? What is the probability that whoever removed the passenger center bolt didn't pull the driver's center bolt? why would anyone take out a spring center bolt? There has to be a reason. (Usually it's because the bolt head is too big for the lift block.)

You also claim that you had to use a come-along to square the axle. But you say that you "tapped the driver's side toward the back" Sorry, but that's not right. If the driver's side MOVED when you hit it, then there's something wrong over there. My guess is that the same person that left out the center bolt on the right also left out the center bolt on the left. And if the u-bolts are torqued correctly, that axle is not moving even if the center bolt is broken. I highly recommend that you check BOTH sides.

People are funny, because they think that spring center bolts break and cause the u-bolts to come loose. But that is completely backwards. The u-bolts come loose, and then the movement of the axle breaks the center bolt. Your situation is unique because the bolt was GONE. It didn't vaporize. Where is it?

And there's nothing wrong with re-using a good leaf spring u-bolt. As long as the threads are good, and the bolt is not damaged, it is perfectly acceptable to re-use them. Usually the threads are not good, and usually they are rusty and junk. But as long as they are clean, and the nuts turn easily by hand, (all the way) then they are fine.

The good news is that you've already fixed the passenger side. Now go finish the job. Then take a string, or tape measure, and loop it around the front and rear axle. Measure both sides. If they are within 1/8 inch, then you are good. Still rooting for you!

James.