Being a rookie I did a Search but could not find dimensions for a stock 1968 trailing arm. Does anyone have a drawing of the stock offset and angles (when looking down at the top view of the arm)?

I forgot to check the arms before rebuilding them. Now I'm having trouble getting enough Toe-OUT on the DRIVER'S side arm. The bushing is against the outboard side of the pocket, and I still need another .125" to be in Toe-Tolerance.

Let me rephrase the question using a diagram of a stock C3 trailing arm.....................................







What would be the Off-set distance between the machine surface and the parallel surface of the arm shown above? Several responses would be appreciated to get an average distance

 

It is 3". If you need another 1/8" it is most likely bent

 

Thanks for taking the time to respond.....

I'll go to the garage and check it now.....I MIGHT be removing the arm this morning to "straighten it" on the 10 ton press.

I'll keep re-checking this thread in the meantime.

The good news is.....with all that new hardware and grease installed/applied last month....I should have the car on jackstands and the arm off in less than 30 minutes!

 

The measurement you're looking for is 1.92 inches from the machined surface to the front of the trailing arm.
Mike

 

I measured.....it seems like 3" would be to the far side of the trailing arm......even at that---the arm is bent about ???????.

1.92 is more in the ballpark of the spot I'm measuring......that would mean that the arm is bent about ONE inch..........no wonder this rookie can only adjust the toe within 1/8" of spec./no room in the pocket for outboard shims.



EDIT: Since the pocket allows a "gap" of 3/8" per side on the trailing arm............I "straightened" the arm to approx. 2" "between the front end of the trailing arm and the machined surface.

After assembling everything and installing the wheel, the difference is very noticeable and I will now be able to set the Toe to the correct specs.

Thanks very much for getting me out of a rookie-jam.



This Problem is Officially Solved!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

 

Good job!
Mike

 

doorgunner,
Question: Did you replace the trailing arm bushing....and if so...what type....original rubber or polyurethane..and whose poly did you use if you did???

Just curious????

DUB

 

Well.....what happened was....a previous owner installed 15 x 8" rims and 295 rear tires....then he decided to "arch" the trailing arms to keep the E-brake brackets on the trailing arms from rubbing on the monster tires......which threw the Toe inboard 1/4" on each tire! I straightened the trailing arm and removed the e-brake bracket for re-location later...I will re-shim the Toe and adjust the Camber on the driver trailing arm tomorrow----then tackle the passenger trailing arm now that I have a clue as to what has been "done".

The previous owner replaced the bushings with good rubber bushings...after "Off-setting "both trailing arms

At least now I/rookie have an idea/plan for finishing the rear alignment!

 

47mm

 

C3 D K..............................thanks!






Rescuing this car is turning into a real learning experience

 

Excellent picture. Thank you for posting it. For everyone else looking at it that measurement should be 1.92 inches.
Mike

 

].......


The above photo was posted by C3 dk as a reference for me to look at.



Now picture this........The previous owner had the arm arched so much that the bushing was only 1/4 " from the straight-edge....


it's a good thing he didn't put many miles on the tires---they would have been worn out in 6 months.

 

I do not mean to throw sticks in the spokes...but there are 2 issues I would like to give a comment on FROM EXPERIENCE.

In the photo's the urethane bushing appear to be Vette Brakes and Products trailing arm bushings. Although these bushings can be installed at a persons home with no really specific tools to stake them...there is a slight design flaw with them. And the flaw is that they are wider than original bushings...so when they get installed...there is a chance that the trailing arm may need to be removed and "tweaked" due to the area needed for an alignment has been reduced...and the trailing arm had an issue that is now identifiable ...but with the original bushings...it could be aligned. I am just saying that this has bit me more than one time and I do not use these bushing any longer...I use other urethane bushings that are just like the rubber style when installed.

The other issue is that using this measuring method is good for a basic idea...but often times the problem that I have run into is that the flat surface where the bearing housing seats against the trailing arm gets tweaked and it can be identified on how well centered the outer bearing/U-joint flange is attached to the spindle in relation to the large hole that is in the trailing arm where the bearing/U-joint flange spins. You would think that it is strong at this mounting area...but do not be fooled. Just saying.

DUB

 

I know exactly what you are referring to (only because I've been "hugging" that trailing arm assembly for two days)......I'm going to the garage now and check overall width of the bushing.

I did pay close attention to the machined-flat area that the hub bolts to---it was in good shape.
But I will measure the hole-to-flange clearance just to be sure.

Thanks for letting me know what to look for so I won't have to remove the trailing arm a third time....but I am getting faster at it......LOL!

 

YEP...before you know it you will snap your fingers and it will be on the ground.

DUB

 

Both of my original arms were bent, basically where they necked down to the skinny part. You could see definite marks from a hyd-press on the outside of each arm and corresponding marks on the insides. My guess was someone made their own "off-set" arms to mount wider tires at some point in it's lifetime.
M

 

The rubber bushings were slightly under 2 1/4" wide....a total of 11/16" stack of shims equaled 3/32" Toe-IN on that rear wheel.

Thanks for making Saturday morning easy! Now......Saturday afternoon is a different story......the A.D.D. kicked in while I was staring at the driver-side front wheel!

The previous owner must have worked at a pipe manufacturing facility......there were no marks on the arm---just a radius at the "smaller" section of the arm.

After I "straightened" the arm and reinstalled it, the 295 tire would have contacted the e-brake bracket when cornering (which explains the scratch/rub mark on the inboard tire wall.....I did as forum members suggested---cut off the E-bracket and saved it to weld on in another location.

Thanks for helping me with this...it would have taken me a month to figure it out on my own!

 

Yup... same here
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M

 

Thanks for the pic.....how do I get the car upside down to weld the bracket on?













But......you never know......me being a rookie )

 

Just move the trailing arms to the other side