Just out of curiosity can it be done? I will be using an adjustable lower control arm in the rear so I can adjust toe and thrust angle as well as an adjustable panhard bar to center the rear end. My question is this, can anything be done to change the camber in the rear? I know on some cars you use shims and stuff to change the angles. I don't mind if I have to modify parts to get the adjustability that I need. Has anyone done this? Are there any parts out there to achieve this? Thanks for taking the time to read this post, Paul Moore

 

No, as far as I know it's impossible. You would have to bend the axle tubes, which would cause the axles to become misaligned.

 

You can't adjust toe either, its a solid rear axle, nothing is adjustable.

 

colonboy14 and ME Leigh are right, it can't be done. Take a rear wheel off and look behind it. There's no cv boot or u-joint and so there's no adjustability.

 

As independant angles(toe and thrust angle) no they can't but I did align my fourth gen with the adjustable lower control arms in the rear. The thrust angle measurement is the difference in toe angles between the left and right sides. For example, if your rear toe looked like this.... -.10 0.0 you thrust angle would be at -.05. I do alignments on cars everyday(I work at a Lexus dealership remember!) and usually if the thrust angle is adjusted to 0 the the toe measurements are dead even between left and right. All I did when I measured the rear in my 4th gen was turn the adjuster until the toe came in to 0, looked at my thrust angle and saw that it was 0 and locked everything down. I know that toe cannot be adjusted by itself so you have to use this method and it will get you close. Maybe I just got lucky with it, who knows.

 

Toe is built into the axle it cannot be adjusted no way no how. By adjusting the LCA length your just moving the axle laterally parallel to the driveline. The only adjusts the pinion angle slightly.

Now i'm not sure what you mean by thrust angle, please define?

 

Errr...Ummm...without giving away TOO many secrets....camber can be adjusted, by a "limited" amount, on a beam axle. Even on stock axle housings. And that's all that I'm going to say about that!! :lala:

I'm sure that theres are some members out there who know what I'm talking about, but my competitors sometimes read this board

Actually...come to think about it...No it is impossible. You can't do it... forget I mentioned it!!! :lala:

 

Hopefully you can read these images. I scanned them from my Toyota Suspension and Handling book, but had to resize them really small due to the 102500 size limit. Here goes 1 of 3..

 

2 of 3....

 

and 3 of 3....

 

Yes you can but its not for the faint of heart.

 

paulmoore,

Now i see what your talking about "thrust angle". You could adjust that by altering the LCA lengths, but that still doesn't change the toe.

However you could slightly adjust the toe (see above posts). It involves big machines.

 

I completely understand what you mean by not being able to adjust the toe. But if you look at the diagram above you can see how it would change it. If the toe measurement is represented as the difference between the front and rear of the wheel, and the axle was perpendicular to the driveshaft, then the toe would be 0 as well as the thrust angle assuming that nothing was bent or damaged. So, if you were to use the LCA's to adjust the thrust angle to 0, your toe would practically be at 0 for all intents and purposes. Let's say that you removed the left LCA and replaced it with a shorter one. The right rear wheel would be shifted outward, the left rear would be inward, and the axle would look like this..... /----/

Since the front egde of the tire has a different reading than the rear of the tire does, your toe would be out of whack as well as the thrust angle. With the adjustable LCA's you do not adjust toe just the thrust angle, however toe will follow it. And the reason why it does is because as long as the driveshaft is hooked up. the rear end will basically 'pivot' from side to side from the rear end yoke.

 

ME Leigh: I just want to clarify that I am not trying to debate with you. I am only trying to explain how I was able to adjust it from my own personal experience. If you do have adjustable LCA's, and access to a state of the art digital alignment machine, I would urge you to take your car to that shop and have them turn the LCA adjusters while you were looking at the live rear end readings and I think that you will see them change. That's only if you are due for an alingment though!!

 

Toe doesn't change, the tires are still parallel. All toe means is that tires aren't parallel to each other. Changing the angle of the rear axle will not change the fact that the tires are still parallel, and have to stay that way. That will only change the thrust angle.

I don't know why you would want to change the trust angle other then to adjust for a bent frame, going in circles, or adjusting for a weight imbalance.

 

Just to square up the rear end and make sure that everything is in line. My 4th gen was in a rear end collision before I bought it so I bought the adjustable LCA's, panhard bar, and torque arm. With the vehicle at ride height I centered up the rear end side to side with the panhard bar, and set thrust angle to 0 with the LCA's. It just so happened that when I set the thrust angle to 0, my toe was also at 0. use the torque arm and put the pinion angle to -2 and she was good to go.

 

Alignment Report on my 83 TA:

FOR THE REAR:

Camber:

L is -1.03

R is -0.87

Toe:

L is 0.10

R is -0.14

Thrust Angle is 0.25

iI guess it sagged a bit over the years..lol.

 

Yep...same thing happened to my car. Well...gravity does take it's toll over the years doesn't it? LOL

 

So i guess i'll go find the oldest 12 bolt i can and install it for better cornering LOL!!!

now theres a trick i bet vsixtoy hasn't tried yet!

on second thought he probably has a rear modified by a NASCAR shop with ball bearings and a slight bend in the tubes!!

 

No I don't, but you better believe I have already spec'ed out a Quickchange aluminum tube rearend for this car in the event I ever need a new rearend for it and I retire it as a daily driver. There are a few tricks I am in secret co-development involving some new rearend suspension features for third gen. The wheel are turning but R&D takes months if not years.

You want rear camber, simply cut here, bend, and re-weld in a measured jig for accuracy. Make sure you are still clearing the alxle housing with the inner axles at the bends. BUT DO NOTE: Do not run more than 1- 1.25* neg camber on the rears or you will excessively wear out the rear inner tire treads on a daily driver.

 

I should also not that even though I do not have more than stock "fixed" rear camber, my rear suspension setup is preped to induce as much roll understeer as possible when on lateral edge. This "kinks the axle forward on the outer tire an slightly pitches the camber more neg as well as increasing the slip angle of the tires to track in the direction of the fronts being turned.

How? Very short LCA's set at optimum geometry angles to promote this with the aid of rear progressive rate springs that will squat the rear more when set into a turn than what linear rears would do. Its all about what you buy and how you set it.

Currently, my rear tires are aging and loosing grip in propartion to the fronts so the 25mm rear bar is a tad excessive and hinders this progression because the rear will slip before compressing as much as it does with fresh tires.- A perfect example how a on-the-fly adj rear swaybar would benefit me to keep the car sharp as things age and change.

 

You can change both the camber and toe in. We used to do it on the stock cars to get them to turn left. It has also been done on roadracers..BUT.... it's awfully hard on the axle splines Some enterprising individuals out there have actually machined the splines egg shaped to allow for this adjustment. Basically, you do it the same way you straighten a truck beam axle. We actually had a fixture that would hold the one end while the other was fit into a press device. A quick search of "adjustable camber rearends" shows a list of track rules that ban rearend camber over 1 degree. If you do this I would use a "c" clip eliminator that would retain the axle if it breaks. Back in the late 80's early 90's Dale Earnhardt lost a race when his camberred rearend broke the axle with about 20 laps left at (I think) Martinsville.
That sort of let the cat out of the bag for the rest of us cheaters.