I'm basically a lazy guy. I want to do this once. Here's the deal. Both trailing arms were rebuilt. Had to replace the Left arm because it was bent. Why? A previous dismantler used a torch to cut the bolt. Heated the arm so much that it twisted...about 20 degrees. Wasn't noticeable with the arm installed. Holes from the burning torch were :)

Marked my shims when I removed them. Have a total of 11/16 on each side.

On the "good" Right side, have 4/16 on the "inside" and 7/16 on the "outside".

On the "bad" Left side, have 8/16 on the "inside" and 3/16 on the "outside".

As you can see the alignment situation is nearly "reversed" as to the number of shims. Being the "**** retentive" NCRS member that I am, friends and other NCRS "buds" have convinced me to use the "holed" shims, not the replacement "slotted" models. Once the "holed" shims are in, you have to take the Trailing Arm bolt out to change them. Question??? My gut instinct is to do the "bad" left like the "good" right and make the shims the same on both sides. This is the way my 63 is, and it has holed shims. DO NOT WANT to have to pull the bolts when it goes to the alignment shop. What do you think of my plan? All input appreciated. The car has never been hit...has no frame damage and all the original body panels. Chuck





[Modified by Chuck Gongloff, 5:06 PM 12/11/2001]

 

Chuck,

Say it ain't so! :)

Heck, you even had me talked into using the slotted shims and now you're turning back to the "dark side" and going with the holes? Guess that I better listen up too... Have to go back to the old style shims if you are!

Thanks again for the springs... They are going to work out great!

Regards,


[Modified by Rowdy Rat, 4:07 PM 12/11/2001]

 

Hi Stan. Glad you like the springs. I'm enjoying the added space on my garage floor since they're gone. It wasn't just you, others too have "taken me aside", and pointed out the "error" of my ways. They have talked me into doing "the right thing" :) Went to Tony's on Saturday, talked to a few other guys, etc. Felt like a leper when I mentioned the dreaded "slotted" shims. Sheepishly bought a set of "holer's". Still have my "slotter's". Will probably start the rear re-assembly this weekend. What do you think of the alignment situation? BTW, I like your signature. Check out this picture. Chuck






[Modified by Chuck Gongloff, 5:17 PM 12/11/2001]

 

Chuck, it is interesting to be able to compare notes on these obscure facts that nobody thinks that anybody ever thinks about.

For what it's worth, and this may be worth jack doo, my 70 was set up with the same amount of shims on both sides. Reading from the notes I recorded in my AIM, the driver side had (2) 1/8" shims on the outside of the arm, and (4) 1/8" shims on the inside of the arm. On the passenger side, the arrangement was the same, i.e. (2) 1/8" shims on the outside of the arm and (4) 1/8" shims on the inside of the arm. Note that no 1/16" shims were used.

I don't know if the car had ever been realigned in the rear, but I do know that the original owner lost a rear wheel bearing resulting in the spindle, spindle support, universal joint and other parts being replaced. The shims may not have been changed at that time, but I believe he was at least charged for an alignment.

One thing to think about is that the number of shims is really determined by the configuration of the frame, and I don't know that you can make any conclusions from the shim set-up for my car. For example, if the frame is slightly out of square in one direction, then the shims have to be installed to make the rear wheels track exactly behind the front wheels and to create the correct rear wheel spacing while filling up all the empty space where the control arm mounts; at least that is the way I would look at it.

Have you considered that the burn marks on your original control arm represent a misdirected effort at camber adjustment rather than an attempt to remove the arm. To adjust the alignment on the old solid axle fords, even the later "twin I-beam" suspensions, they had to heat the axle and bend it (holy schmoley, we are talking smoke-stack industry here). I don't see how the guy could twist a control arm 20 degrees trying to remove it, unless that was his original objective.


[Modified by Chuck Sangerhausen, 3:36 PM 12/11/2001]


[Modified by Chuck Sangerhausen, 3:42 PM 12/11/2001]

 

Chuck..
Having someone else work on your car can be very stressful, and there is
always the possibility they could cause some damage.
I would use the slotted shims for the alignment and then go home and one day when you feel ambitious, replace them with the exact configuration
using the "holer's".
I wouldn't think this would change the alignment.
Just a suggestion.
Thanks, Barry

 

Patrick: My goal is to take it to the alignment shop and have them say.."Man, that rear end toe is right on the money", "don't need to touch it". I know how tough it is to pull that bolt and change shims. I've "been there, done that" before. :) It's hard enough without the spring attached. It's virtually impossible with the spring torquing the arm.

Chuck: Don't think it was a camber adjustment attempt. The guy had actually burned a few holes in the trailing arm itself, near the pivot bushings. I think he got it too hot, then tried to gorilla the arm out. He obviously got it out, but twisted it. I didn't measure the "twist" with a protractor. Maybe 20 degrees is a bit exaggerated. 15 might be closer. In any event it is very obvious when you stand the bent arm up next to a good, straight arm. The twist is up in the most narrow point of the trailing arm....inside the "pocket" in the frame. It was not noticeable with the arm on the car. Sounds like the alignment shims from your car were equal on both sides, and also symmetrical in placement. I know this is a "crap shoot", trying to guess-timate shim counts. Chuck

 

Am I missing something?? Are shims judged, or are we just tryng to be good NCRS boys :)

 

Shims are judged, as is the presence or absence of the cotter pin used to retain the slotted shims. Chuck

 

Tony did the rebuild of the T Arms and A Frames, but I'm the "general contractor" on this job. I took all the pieces off, and brought them to him. I'll be re-assembling the car and will likely take it for an alignment locally. Chuck

 

Chuck,

There is a neat peice in a little handbook I got from Herb Adams many years ago about setting alignment for your Corvette at home... I'll photocopy the pages that apply and snail mail 'em down to you.

Check out the new Grassroots Motorsports magazine if you get a chance (if you can't find a copy, let me know and I'll copy the article for you)... Cover story is "Old Mini vs. New Mini"... About a four or five page article. I won't spoil it for you, but the old Mini does pretty well. :)

I like the photo! I remember Collinsville was very hot... 100+ every day we were there. Lots of fun on the road tour though!

Regards,


[Modified by Rowdy Rat, 8:36 AM 12/12/2001]

 

For some unknown reason, I received a "free" issue of Grassroots Motorsports this month. Never subscribed to the mag. Saw the Mini article and the Mini cover. Wish I still had my 67 Cooper S. Sold it to a guy in Valley Forge, PA about 4 years ago, and have never seen it again. Chuck

 

Chuck -

IMO, there's no way to accurately "estimate" the correct shim pack and get the toe absolutely equal on both sides (which is critical); too many variations in all the components. I'd use slotted shims, have the alignment done correctly, then swap them at home for an identical shim pack with the "hole" shims. The "hole" shims require a lot more time ($$$) at the alignment shop, and are more likely to cause the tech to call it "close enough" early in the process rather than to disassemble the damn bolt again and do it right.

In production, the rear toe fixture held the hubs in the correct toe position with the spring compressed to ride height (with the frame upside down), and we just "stuff-shimmed" the resulting gaps in the frame pockets on both sides of the bushing; there was no "standard shim pack", and the car-to-car variations were significant.

 

Chuck, man, I don't think this is gonna happen unless you're the luckiest guy I know. You can probably get close, but unless the alignment guy's willing to accept a high degree of mediocrity (and I hope he won't), he's gonna have to add or subtract some shims. If you are able to set it up within the tolerance, you can probably sell your method for a lot of money. :cool:

 

Put both rebuilt arms on today. Didn't take anyone's advice :) Used the holed shims. Set the "good" right T Arm with the same shims I had removed and marked before the rebuild. Decided to do the left one the same way. Used the identical shim configuration. Will need to get it aligned anyway. I've "been there, done that" before with rear hole shims at my alignment shop. The fellow I use does a lot of Corvettes, and has done them for 30 years. He really doesn't mind doing them as long as his customers realize the work involved. Since all is new back there, it shouldn't be too hateful to change some shims if I need to do so. I'm just tired of looking at the car on jackstands. Maybe I'll get lucky. Chuck