Have you been driving a crooked truck?

[Swar]

Good morning, so I put "new" rubber on and wanted to check the toe in. I learned about the string method so I tried it and found the rear wheels are not lined up with the front.
The rear end appears to be pushed to the right/passenger side.

[Swar]

Everything seems to be straight up front, including the pitman arm and idler arm.
According to the string though, things are off center.

[FlameOut]

Mine may be off a bit too. I'm having a heck of a time getting my newly installed bed lined up. Not sure if cab is off center too. I may have to try this method to see if my frame may be out of wack a bit

[joeydurango]

Not sure on my truck... but my old Nova used to leave four tire tracks on a dirt road.

[Swar]

Haha Joey that sounds pretty bad.
Bill, I think that's my problem, the frame seems to be tweaked to the right.
When you string it up, it's best if you can get the string in the center of the wheel, in my case, the truck rides too low for that, so it's up as high as it will go. I have the same measurement at each wheel though.

[67ChevyRedneck]

The track width on GM trucks, even today, is greater on the front than the rear. That's why I put 8's on the rear and 7's on the front of my truck with the same offset.

[Swar]

Good point. However, my truck is bagged with aftermarket control arms, which appear to shorten the track.

[Swar]

It gets weirder...
I adjusted the track bar in all the way, and the wheels still aren't lining up.
The frame is definitely tweaked to the right.

[Swar]

This is the strangest part, the owner before me had cut the frame, but I don't know why.
This is an original swb frame, the trailing arm cross member is riveted in from factory.
Someone cut the frame and possibly added the rear end from a different truck.
I've been driving this thing for 12 years now and never had a problem, it feels straight as an arrow going down the highway.
It wasn't until I started measuring things and did the string method that I found these problems, so I guess I have some work to do.
Oh yeah, and my bed is out of square by an inch, so yes I have been driving a crooked truck.

[DBK81]

Adjust your panhard bar, that's what is causing you grief I bet.

[Swar]

Well, I did. But the string shows the whole rear end, with the frame is shifted to the right.
So most likely the frame is twisted, or welded out of square.

If anyone wants to learn the string method, watch this video:

https://www.youtube.com/watch?v=0sguZ-gRF9I

[hugger6933]

Go and search my threads on the X method. That will help you find where your problem lies. If you can't dig up anything I can go through it with you. Too bad your not closer my frame machine is just sitting empty it was probably something I could have done without but I had to have a frame machine.[Some day I'm adding two more towers to make it a 4 tower machine.]Jim

[Swar]

Thanks for the help, much appreciated. I searched but no luck. Can you send me a link? Or explain the x method? Thanks

[snipescastle2]

When I changed rear ends on Mine, I used a 12 bolt posi rear end out of a '64 C10, basically the same rear end, except the track bar was different. Which necessitated fabricating a new track bar. I had replaced the bushings in my control arms while it was apart as well. It wasn't until after I bolted on my bed that it was evident my tires were not centered in the wheel wells/ chassis.
Since I made my track bar adjustable, it was easy to center the wheels, maybe that is the problem you are having now that it's lowered?
Ben

[snipescastle2]

When I changed rear ends on Mine, I used a 12 bolt posi rear end out of a '64 C10, basically the same rear end, except the track bar was different. Which necessitated fabricating a new track bar. I had replaced the bushings in my control arms while it was apart as well. It wasn't until after I bolted on my bed that it was evident my tires were not centered in the wheel wells/ chassis.
Since I made my track bar adjustable, it was easy to center the wheels, maybe that is the problem you are having now that it's lowered?
Ben

[67ChevyRedneck]

Centering should be easy, looks like he already has the ECE (or equivalent) adjustable track bar.

[snipescastle2]

Sorry! double post

[davepl]

Long thread, so I might have missed it, but isn't the rear track width narrower than the front? I remember that because it seemed so weird.

So if you don't take the track width front and rear into account you'll never get them to line up without spacers to account for the difference.

If you're past that point, just ignore me!

[Swar]

Originally Posted by 67ChevyRedneck

Centering should be easy, looks like he already has the ECE (or equivalent) adjustable track bar.

You are correct, the ECE track bar had to be mounted below the trailing arm to clear the frame, but still works fine.

The frame itself is the problem, not the track bar adjustment.

Snipes & Dave, thanks for your input. What I realized by using the string is that my front wheels are tracked slightly narrower than the rear wheels.

I can get a straight line off the passenger's side rear wheel.
The string is about an inch away from the front wheel.

However, the driver's side string hits the front wheel before the rear sidewall.
This is with the track bar adjusted all the way to the driver's side.
This picture shows the rear wheel, look at the space.

[kehstr]

Originally Posted by DBK81

Adjust your panhard bar, that's what is causing you grief I bet.

agreed, especially with a lower truck

[DBK81]

Sorry. Like a few of us I should have read the whole thread, didn't realize your whole frame was shifted. That's a whole other can of worms.

[clemsonteg]

I have only seen the string method using 4 jackstands, not 2. Using 2 jack stands on each side and setting the string on one side so that on the rear wheel it is whatever you like (1, 2, 12 inches) from the forward and rear position of the rear tire which should establish a straight line all the way to the front. Then you can measure whatever number you wish that is greater than the track width to locate the other 2 jackstands on the opposite side of the truck and verify it forms a straight line with the other rear wheel and is parallel to the first string.

I am not discounting that the frame may be bent or tweaked. It is certainly possible after 40+ years, not to mention suspensions modifications and who knows what amount of goobering PO's have done. With that said, it might be worth checking the wheels as well to make sure they are all the same width and offset, especially using the measuring method you are by wrapping the string around the rear tires.

[Swar]

Originally Posted by DBK81

Sorry. Like a few of us I should have read the whole thread, didn't realize your whole frame was shifted. That's a whole other can of worms.

No problem, there's a lot going on here. It really is a can of worms and I just opened it.

Originally Posted by clemsonteg

I have only seen the string method using 4 jackstands, not 2. Using 2 jack stands on each side and setting the string on one side so that on the rear wheel it is whatever you like (1, 2, 12 inches) from the forward and rear position of the rear tire which should establish a straight line all the way to the front. Then you can measure whatever number you wish that is greater than the track width to locate the other 2 jackstands on the opposite side of the truck and verify it forms a straight line with the other rear wheel and is parallel to the first string.

I am not discounting that the frame may be bent or tweaked. It is certainly possible after 40+ years, not to mention suspensions modifications and who knows what amount of goobering PO's have done. With that said, it might be worth checking the wheels as well to make sure they are all the same width and offset, especially using the measuring method you are by wrapping the string around the rear tires.

Very good advice. Thanks. I will check the rim & tire measurements, and try 4 jack stands to get 2 parallel strings, then i can get the string in the center of the wheels.

[WarMonger]

I watched that string video. That was pretty cool. I'm gonna have to go home and try that out now.

[DBK81]

I don't dare try this on my vehicle, ignorance is bliss hahaha