Leaf Centre Pins out of square

[[memphis]]

I am building a custom frame.
WB is around 86”

Unfortunately, measuring centre pins with all four main eyes bolted in and having the frame upside down (springs unloaded)

I am 3/8” or so out of square including a bit of measuring tape sag

When I was measuring the actual frame corner to corner I was within 1/8” to 3/16”

It’s all handmade by me so when is good enough good enough? I don’t want the axle dog tracking down the road but I’m not really sure how to fix this.

I haven’t moved my leaf springs around to determine if it’s a spring issue. I guess that’s the next step?

My main eye mounts are just tacked in place but measuring square on these I am within a 1/16”

 

[Clb]

Old frame guys used 1/8 as acceptable, 1/4 max.

Can you pull tape and read accurately? ( same exact spots)
Use a string and remesaure the ink marks?

Are the eyes to pin equal?
Are the pins bent/ loose?
Are the arches equal?

Kinda sounds like you have a hanger issue...

 

[Slander]

Did you forget to put a bushing sleeve in? If it was my rig and the mounts were all square I would just run it. I mean realistically when one side sags more than the other, like all leaf spring trucks do, you will be more out of square than that anyway.

 

[BDK]

My 1994 Explorer frame is almost a inch lower on one side. Ford said that was within specs when I noticed it while it was still under warranty.

 

[Squamch]

My leaf swapped 4runner somehow ended up about 1/4" out on leaf mounts. It was pretty bent to begin with. I did the alignment so it feels straight, apparently if you look hard you can see it dog tracking, but there's enough other WTF going on that it's not the first thing you notice

 

[[memphis]]

Old frame guys used 1/8 as acceptable, 1/4 max.

Can you pull tape and read accurately? ( same exact spots)
Use a string and remesaure the ink marks?

Are the eyes to pin equal?
Are the pins bent/ loose?
Are the arches equal?

Kinda sounds like you have a hanger issue...

Everything is “new” within the last four years because I build slower than cold tar.

I did measure off some fixed points:

Inside face of rear bumper to centre pin and found a different length. Basically 1/4” which might be my wheel base difference I found side to side

Inside face of front bumper to pins was within 1/16 side to side

The one rear spring (all four are the same part number) has a lower arch than the rest and appears to be physically shorter than the rest.

I’ll try swapping it around and see what I come up with.

 

[AKnate]

Old timer body/frame guy once told me it was common for off the factory floor stuff to be off 1/2".
Dunno how true that is, but given panel fitments of 70s-80s stuff, probably is.

I know my Jeep was off about 3/8" before I cut the factory stuff off. And it went down the road fine.

 

[Clb]

2 slow^^^
yea man

Try using the fixed hard points as reference.
The issue of the spring will foul you up.
Can you Plumb Bob to the floor?
If it's all effd up forget it.
Yes it's not a frame plate but if the plane is close to level/flat it would work.
Square the frame and suspension mounting, then Square the axles.
Good luck , keep plugging away.

 

[[memphis]]

Just so you guys don’t think I’m completely dumb.

On the rear I had to change my fixed reference point because there was a tack weld in the way so you’ll see a measurement of 17.xx” instead of the front

Edit:

My rear fixed mounts appear to be a little out but I plan to swap a spring side to side and measure again

I can slip into all of the suspension mounts with threaded rod except for the leaf pack I was doubting which I’ll post below to avoid confusion

 

[[memphis]]

Shackles mounts are inline on the rear. Please ignore the nasty vertical up welds, I plan to grind those out and cap them

As you can see one spring is in fact shorter than the other… not to mention the eye is twisted and even twisting the thread rod around doesn’t straighten it out

Edit:

The pic measuring 17-11/16” is the spring I suspect is short… which could be the entire issue

The other side is 17-7/8”
I plan to move one of the front springs to the back as I figure they are pretty consistent side to side as a test but will have to do it later. Parental duties now!

So

 

[[memphis]]

I swapped one of the front springs to the position I was questioning (driver rear) and what do you know… the wheel base got longer!

For shits I also checked the frame mounts and the rails are twisted a bit from the initial welding. I am sitting on a pipe wrench taking this photo. I’m sure I can straighten it a bit with some heat

 

[Mr Priceless]

can you cross diagonally measure the distance between rear (passenger) inner hanger mount eye to front (driver) hanger mount eye? and vice versa? I'm basing this question off of tandem trailer measurement experience. those two numbers would give me my square reference


edit, disregard

 

[Skinny]

Depends

Are you building to British or Japanese standards? 🤣

British is looks good run it mate. Japanese is the measurement is off by a millimeter, time to kill your family.

Seriously on a leaf sprung offroad truck close is pretty good. There is so much slop and imprecision with leafs it won't matter. Fuck if I could keep all my leaf sprung rigs from squatting on a random corner I'd be happy.

 

[[memphis]]

Depends

Are you building to British or Japanese standards? 🤣

British is looks good run it mate. Japanese is the measurement is off by a millimeter, time to kill your family.

Seriously on a leaf sprung offroad truck close is pretty good. There is so much slop and imprecision with leafs it won't matter. Fuck if I could keep all my leaf sprung rigs from squatting on a random corner I'd be happy.

I’m trying to keep my tolerances tight so when it comes to the next stage of fitment everything should go together like Lego. I understand stuff is going to move around and settle but the more I can account for that… the better in my opinion.

Obviously I can’t control the quality and fitment of the leaf springs but I am going to ask Rubicon Express for help. These things have never seen a load on them

 

[Clb]

If all 4 are new and 1 is different....
I say call them NOW.
Boy howdy
Save the headache
Eta
Removed the china rant from this one...

 

[[memphis]]

If all 4 are new and 1 is different....
I say call them NOW.
Boy howdy
Save the headache
Eta
Removed the china rant from this one...

Due to the timeframe they may tell me to pound sand. It’s been +3 years I’ve been accumulating parts.

On their website it does say lifetime warranty on their products and this appears to be a manufacturer defect

 

[Clb]

lifetime 👍
Apparently still means something to some of us

 

[Skinny]

Good luck

I bought a set of springs from Rockauto. I believe they were made by Dayton. First of all Rockauto sucks 90% of the time. Firmly believe the whole thing is run by AI, not a single human on staff.

Dayton doesn't give a shit either.

Leafs installed and one say and inch and a half lower. Granted I bought them a year ago but the stickers still on them, not a single road mile. Go pound sand.

Personally I'd rather buy bags of shit from a vendor that stands behind those bags of shit.

 

[mobil1syn]

so the frame and fixed points are all within an acceptable tolerance but the leaf springs with not bolted to a shackle is slightly off?

 

[[memphis]]

so the frame and fixed points are all within an acceptable tolerance but the leaf springs with not bolted to a shackle is slightly off?

Correct
With the shackle disconnected or connected there is a discrepancy.

The spring causing this fuss appears to be about 1/2” to 5/8” of an inch shorter over all and it sits lower than the rest of the packs by about 1/2” so it’s not a matter of it settling and matching the others

 

[[memphis]]

My replacement spring showed up from the Jungle. No answer from Rubicon Express regarding a warranty… the spring is noticeably longer and installed but I’m still out of square.

I am going to use a string line on the pins to see just how off a tape measure is. I know it’s never going to be perfect but the fixed mounts as correct as they seem to be… are only tacked in place and can be moved if required

 

[[memphis]]

Placed the frame under tension as I found the pins to be about 5/16” out of square. With it under tension with a ratchet strap I can get the pins square but as soon as I loosen tension it bounces back to where it’s out… advice?

 

[mobil1syn]

run some welds on the side of the frame you want to pull

 

[Clb]

Sounds like the frame is twisted didn't you say it was square on pg. 1?

Have you measured the level plane of the frame?

 

[[memphis]]

Sounds like the frame is twisted didn't you say it was square on pg. 1?

Have you measured the level plane of the frame?

I haven’t measured level plan
On page one I said the frame was around 1/8 to 3/16 out of square

But my fixed mounts appear square. Even with the strap pulling it, the fixed mounts are within a 1/16-1/8” of each other

 

[Clb]

I like the weld a bead to draw the frame in the desired direction mobil posted above.

Find out if the level plane is out, causing the issues you fix with the strap.

Figure out the location of the bead that you are looking for with the strap.

My .02 but I'm not on site, and could be wrong

 

[Slander]

Personally I would stop measuring the squareness at the leaf spring center pin, there are too many factors affecting that. The spring pin hole could be drilled in the wrong spot at the factory, the spring compressed slightly more than the other, the frame is twisted a bit, the bushing deflected and so on.... it's going to cause you to start cutting stuff off and moving things around just to hit dead on, and you could throw it even further out of whack, or waste even more time for no real gain.

 

[Winchested]

Personally I would stop measuring the squareness at the leaf spring center pin, there are too many factors affecting that. The spring pin hole could be drilled in the wrong spot at the factory, the spring compressed slightly more than the other, the frame is twisted a bit, the bushing deflected and so on.... it's going to cause you to start cutting stuff off and moving things around just to hit dead on, and you could throw it even further out of whack, or waste even more time for no real gain.

Ya really most leaf spring perches have bigger holes than the center pin head. Friggen move the axle around to square it up frig.

 

[[memphis]]

Ya really most leaf spring perches have bigger holes than the center pin head. Friggen move the axle around to square it up frig.

I’m building a zero tolerance rocket ship damn it! Or hoping for better tolerance than Tesla 😝

The good news is the replacement spring I just ordered and installed fixed and confirmed one issue

 

[the_ham_sami]

97 Explorer I put Deavers on was 1/2" out of square when it came to me. OEM hangers and bumpstops were 1/2" farther forward on one side, relative to the front OEM lower control arm mounts. No idea on the vehicles history but there weren't any obvious signs of crash damage. We squared up the rear end/spring hangers with the LCA mounts and called it good.