alignment question

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Belgian1979
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alignment question

Post by Belgian1979 » Mon Mar 25, 2013 3:44 pm

I have an old alignment rack, that I was able to buy for a couple of bux. It still uses elastics to connect the various sensors etc, but seems to work okay.

I'm new to this tool, and just this weekend used it fully for the first time to set my alignment after a full body off resto. Anyway the procedure to set alignment was : finding vehicle axle, setting rear camber, rear toe in, front caster, wheel turn toe out, camber with toe for that wheel at 0, and finally toe in on the front. Then a control measurement of total toe with axle offset.

After a couple of tries with switching/changing several shims I got it okay, in the sense that I finally got front axle offset right after I managed to get caster in te front equal. I got a minor difference in camber on the front after that from 13' vs 17' minutes (which should have been 15'). I cannot seem to be able to correct that anymore due to not thin enough shims.

Anyway, my question : I reconnected the heads today to verify everything I did yesterday and it comes up okay, but front toe seems to be off. Off in the sense that total toe in is correct but right and left toe is wrong....

Is there something I could be missing here ?

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Re: alignment question

Post by Olefud » Mon Mar 25, 2013 4:56 pm

Are you saying the steering wheel wasn’t centered the same?

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Re: alignment question

Post by Belgian1979 » Mon Mar 25, 2013 5:16 pm

Olefud wrote:Are you saying the steering wheel wasn’t centered the same?
No, steering wheel is on center. It was blocked there while setting toe.
There is no indication as to wat the center on the steering wheel is, except for the flat on the steering housing input shaft that needs to be in the 12 o'clock position, combined with the pitman arm turning point and connection to the center bar inline. I turned it full left and full right counting amount of turns and turned it back half way. The pitman arm seemed to line up well.

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Re: alignment question

Post by af2 » Mon Mar 25, 2013 5:45 pm

Belgian1979 wrote:I have an old alignment rack, that I was able to buy for a couple of bux. It still uses elastics to connect the various sensors etc, but seems to work okay.

I'm new to this tool, and just this weekend used it fully for the first time to set my alignment after a full body off resto. Anyway the procedure to set alignment was : finding vehicle axle, setting rear camber, rear toe in, front caster, wheel turn toe out, camber with toe for that wheel at 0, and finally toe in on the front. Then a control measurement of total toe with axle offset.

After a couple of tries with switching/changing several shims I got it okay, in the sense that I finally got front axle offset right after I managed to get caster in te front equal. I got a minor difference in camber on the front after that from 13' vs 17' minutes (which should have been 15'). I cannot seem to be able to correct that anymore due to not thin enough shims.

Anyway, my question : I reconnected the heads today to verify everything I did yesterday and it comes up okay, but front toe seems to be off. Off in the sense that total toe in is correct but right and left toe is wrong....

Is there something I could be missing here ?
Why are you working on the rear??? Unless in an accident the front is where you need to address..
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Re: alignment question

Post by Belgian1979 » Mon Mar 25, 2013 6:22 pm

af2 wrote:
Belgian1979 wrote:I have an old alignment rack, that I was able to buy for a couple of bux. It still uses elastics to connect the various sensors etc, but seems to work okay.

I'm new to this tool, and just this weekend used it fully for the first time to set my alignment after a full body off resto. Anyway the procedure to set alignment was : finding vehicle axle, setting rear camber, rear toe in, front caster, wheel turn toe out, camber with toe for that wheel at 0, and finally toe in on the front. Then a control measurement of total toe with axle offset.

After a couple of tries with switching/changing several shims I got it okay, in the sense that I finally got front axle offset right after I managed to get caster in te front equal. I got a minor difference in camber on the front after that from 13' vs 17' minutes (which should have been 15'). I cannot seem to be able to correct that anymore due to not thin enough shims.

Anyway, my question : I reconnected the heads today to verify everything I did yesterday and it comes up okay, but front toe seems to be off. Off in the sense that total toe in is correct but right and left toe is wrong....

Is there something I could be missing here ?
Why are you working on the rear??? Unless in an accident the front is where you need to address..
Car was body off restored. Everything was apart and put back together...

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Re: alignment question

Post by Olefud » Mon Mar 25, 2013 6:52 pm

Maybe I misunderstand the symptoms. But if the steering shifted it would add to one side while subtracting from the other while not changing the total toe –assuming no Ackerman.

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Re: alignment question

Post by Belgian1979 » Mon Mar 25, 2013 7:21 pm

Olefud wrote:Maybe I misunderstand the symptoms. But if the steering shifted it would add to one side while subtracting from the other while not changing the total toe –assuming no Ackerman.
How can it shift ? Everything is in a fixed relationship to the other component. The only thing that can be adjusted are the steering arms.

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Re: alignment question

Post by Olefud » Tue Mar 26, 2013 11:42 am

I’m not there so I’m only guessing. Keep in mind the compliance and lash in the steering system. Often the steering wheel can be turned from side to side without affecting the wheels. In view of this I’m guessing that when you removed and remounted the sensors the wheels moved a bit to change the individual wheel toe while maintaining the overall original toe setting, or some similar upset.

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Re: alignment question

Post by Belgian1979 » Wed Mar 27, 2013 5:04 am

Olefud wrote:I’m not there so I’m only guessing. Keep in mind the compliance and lash in the steering system. Often the steering wheel can be turned from side to side without affecting the wheels. In view of this I’m guessing that when you removed and remounted the sensors the wheels moved a bit to change the individual wheel toe while maintaining the overall original toe setting, or some similar upset.
Thanks !! Seems you were right. There was too much play in my steering housing, causing the steering wheel to turn without the wheels turning and probably not returning exactly to their initial position. Corrected play and it came in right.

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Re: alignment question

Post by Belgian1979 » Tue Apr 02, 2013 5:03 pm

I have yet another question. After a small testdrive, I noticed the car was nervous with regards to steering input. Could this be caused by too little toe in or by too much ?

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Re: alignment question

Post by TEROL » Tue Apr 02, 2013 6:37 pm

You probably need more caster.

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Re: alignment question

Post by Belgian1979 » Wed Apr 03, 2013 9:56 am

TEROL wrote:You probably need more caster.
Not sure. These cars were designed for 2 3/4 caster. I'm running an offset upper A-arm which currently gives me 5 1/2. I think this should be plenty.

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Re: alignment question

Post by flyingwedge » Wed Apr 03, 2013 12:04 pm

>>Mr. 1979, you have checked and negated bump steer, throughout suspension travel range ? Scrub radius is acceptable ? Eccessive Ackerman can act "darty". Good Luck, flyingwedge. :)

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Re: alignment question

Post by ijames » Wed Apr 03, 2013 5:02 pm

Belgian1979 wrote:I have yet another question. After a small testdrive, I noticed the car was nervous with regards to steering input. Could this be caused by too little toe in or by too much ?
If the problem is toein, too little will make it nervous, way too little will make it do donuts by itself, and too much will just scrub rubber off the front tires and wear them out faster and faster as you go to more and more toein.

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Re: alignment question

Post by Belgian1979 » Thu Apr 04, 2013 4:08 am

flyingwedge wrote:>>Mr. 1979, you have checked and negated bump steer, throughout suspension travel range ? Scrub radius is acceptable ? Eccessive Ackerman can act "darty". Good Luck, flyingwedge. :)
concerning bump steer, it still is stock and on a 1979 corvette there is actually some bump steer. To get that minimized would mean changing/modifying the center steering link, which is not possible.

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