How to measure a frame to see if it’s straight? (1 Viewer)

[Old74FJ40]

Hello all! I recently bought an FJ40 project. Long story short, someone had cut the frame in half and Jerry rigged it with another half of a frame to make one. In the interest of safety, I am looking at buying a frame for it.

Question is, what measurements do I need to take to make sure the frame is square?

I put a level on the body mounts and they are perfectly level. Want to make sure I am getting a straight frame. Thank you all in advance! Have a good day.

 

[brian]

In some of fsms

 

[45Dougal]

Id start by measuring the triangulation across known symmetrical points.
I seem to remember it's easier if you do it upside down??

chassis/frame dimensions fj40

i just pulled the body off the frame of my 40. i noticed that the frame was slightly bent up.does any one have the original dimensions of the frame or can anyone direct me to a site where i can find a layout/bluprint?i believe i saw a site before just cant remember where. :-/tnx

forum.ih8mud.com

 

[Old74FJ40]

Thank you!

 

[charliemeyer007]

Do you have a local frame shop? There must be some sort of data base they access for the computer alignment and such. Perhaps for a few bucks they could print out the specs.

 

[Mark Jennings]

In the Chassis and Body FSM….there is a whole section on dimensions and frame repair.

 

[Paul_A]

I would start with diagonal measurements from front right to back left, then the other way, compare the measurement and see how square. Then look across to see how much torque there is. It's just a start, but if the numbers add up you might be OK.

 

[bikersmurf]

Hello all! I recently bought an FJ40 project. Long story short, someone had cut the frame in half and Jerry rigged it with another half of a frame to make one. In the interest of safety, I am looking at buying a frame for it.

Question is, what measurements do I need to take to make sure the frame is square?

I put a level on the body mounts and they are perfectly level. Want to make sure I am getting a straight frame. Thank you all in advance! Have a good day.

I have swapped a newer frame into my 40 and know how much work is involved to prep and swap in a new frame. Unless there is something else wrong with your current frame, I'd have the join in the frame fixed and continue on with your build.

 

[jim land]

Use 4 jack stand , two under the front frame horns and two in rear , under the rear crossmember (bumper) close to the shackles hangers
Make the rear level using small shims under the stand
Next , make the front level , if it is twisted it can not be level front and rear and one of the corner will lift off the stand

Hope i make this understandable

 

[Mark W]

I have swapped a newer frame into my 40 and know how much work is involved to prep and swap in a new frame. Unless there is something else wrong with your current frame, I'd have the join in the frame fixed and continue on with your build.

Depends on just exactly what has been done to the frame that is under the rig right now. I've seen some scary stupid stuff done when backyard hacks start cutting and welding on frames. I have also done plenty of frame up projects. I'd take the new frame approach over trying to fix someone elses death trap any day.

Mark...

 

[Fedtime]

I pulled the frame out of my Bj42 for sand blasting and repair. To check it as my work progressed, I placed the frame on a flat concrete floor, then took the triangulation measurement mentioned above. I aimed for, and achieved, a 1/16 of an inch max variance, corner to corner which I think was close to stock.

 

[Old74FJ40]

Depends on just exactly what has been done to the frame that is under the rig right now. I've seen some scary stupid stuff done when backyard hacks start cutting and welding on frames. I have also done plenty of frame up projects. I'd take the new frame approach over trying to fix someone elses death trap any day.

Mark...

That’s the issue. The PO hacked the crap out of it. My kids will be riding in it and I am not taking the chance of using a compromised frame.

 

[Old74FJ40]

Ok. I measured…

Rear driver to front passenger: 145 1/2
Rear passenger to front driver: 145 3/4

I am guessing this means it’s is tweaked to some degree…am I correct?

 

[Homey15]

Ok. I measured…

Rear driver to front passenger: 145 1/2
Rear passenger to front driver: 145 3/4

I am guessing this means it’s is tweaked to some degree…am I correct?

I would not be the least bit concerned about 1/4" variance on a ladder frame chassis. That small of an amount of racking in the frame should cause zero body alignment issues, and certainly won't affect the way it drives/handles to any degree you'd ever notice. I wouldn't be at all surprised if that amount was within allowable tolerance when it was new.

 

[franklin40]

i would agree that amount of variance is not enough to worry about. it’s the actual hack job/modifications i’d be worried about. if it was cut and not welded or gusseted correctly that’ll be way more dangerous than a slightly off square frame. you’ll never notice 1/4 inch!!

 

[45Dougal]

Sounds pretty small.
How do the other smalls triangulation look?

Also.. its a Toyota, so maybe time to buy a metric tape measure ?

 

[456z]

My view,
1/4" difference hypotenuse on frame rail ends tells me generally how close the frame might be and nothing more.

Most important hypotenuse is on the spring mounts ( non shackle ends first) as this is what aligns the axles.
This becomes the square that all else works from. Tolerances for this would be less than my old eyes can see on a tape.

Shackle ends next also making sure they are centered left/right with center line of spring mounts.

Short wheel base means alignment is more critical to avoid white knuckles.