Notices
928 Forum 1978-1995
Sponsored by:
Sponsored by: 928 Specialists

Wheel Alignment

Thread Tools
 
Search this Thread
 
Old 12-28-2008, 10:11 PM
  #1  
Michael Robinson
Instructor
Thread Starter
 
Michael Robinson's Avatar
 
Join Date: Jul 2002
Location: Morgantown, WV
Posts: 142
Likes: 0
Received 0 Likes on 0 Posts
Thumbs up Wheel Alignment

Hello All,

I will be doing a wheel alignment tomorrow at a friends shop who happens to have an alignment rack. I have done my 2004 GMC pickup on it. It is a Hunter brand alignment rack and is capable of aligning all 928's (not that there could be too much difference between years). This will be my first attempt at aligning my 928 as I have had some Porsche shops do it in the past and have done it incorrectly (ie. lifting the front end suspension off the ground). But I have heard that the front lip (1986) has to be removed to get an accurate alignment. I have never heard of this and believe that that is a false statement unless someone states otherwise. I realize too that the 928 will have all 4 wheels adjusted.

The following is where my alignment on my 86 928s was on 6/22/01 done by YARK Porsche in Toledo, OH. (I know I keep an amazing record of all things done to my 928.)

All stated in DEG.

L/F: Cam: -0.96; Cast: 3.58; Toe: 0.15
R/F: Cam: -.077; Cast: 3.11; Toe: 0.15
Front: Cross Cam: -0.19; Cross Cast: 0.48; Total Toe: 0.30

L/R: Cam: -1.03; Toe: 0.07
R/R: Cam: -1.08; Toe: 0.17
Rear: Total Toe: 0.24; Thrust Angle: -0.05

I hope to come close to these tolerances tomorrow and hope it goes well. Any suggestions or comments please advise.

Michael Robinson
1986 Porsche 928s
BLK/BLK 5SPD
175+K
Un-molested...
Old 12-28-2008, 10:45 PM
  #2  
jcorenman
Rennlist Member
 
jcorenman's Avatar
 
Join Date: Jan 2008
Location: Friday Harbor, WA
Posts: 4,062
Received 317 Likes on 153 Posts
Default

Michael,

By "front lip" do you mean the spoiler? I can't imagine why that would need to be removed,. Certainly the wheels don't care and that's what you are aligning.

The spec for front toe is 15' +/- 5', that's total toe, not per wheel. They would set each wheel at 7.5' toe-in, that's 0.12 deg so they were quite close. The rear is spec'ed per wheel.

I would try to get better left/right symmetry for front caster/camber but that's just me being a perfectionist/nutjob.


Name:  Pages from 928 Workshop Manual (complete).jpg
Views: 319
Size:  68.9 KB
Old 12-28-2008, 10:50 PM
  #3  
largecar379
Three Wheelin'
 
largecar379's Avatar
 
Join Date: Jan 2007
Location: not where you think I am
Posts: 1,466
Likes: 0
Received 0 Likes on 0 Posts
Default

only time the front spoiler needs to be removed is if you can't drive onto the rack without tearing it off.....in which case, you can place 2x10's at the ramps to raise the attack angle of the car versus rack.....

DO NOT JACK UP THE CAR PRIOR TO ALIGNMENT.




--Russ
Old 12-28-2008, 11:21 PM
  #4  
6mil928
Race Car
 
6mil928's Avatar
 
Join Date: Sep 2007
Location: No where Oklahoma AKA "The Dust Bowl" In The Arm pit Of Hell
Posts: 3,663
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by jcorenman
Michael,

By "front lip" do you mean the spoiler? I can't imagine why that would need to be removed,. Certainly the wheels don't care and that's what you are aligning.

The spec for front toe is 15' +/- 5', that's total toe, not per wheel. They would set each wheel at 7.5' toe-in, that's 0.12 deg so they were quite close. The rear is spec'ed per wheel.

I would try to get better left/right symmetry for front caster/camber but that's just me being a perfectionist/nutjob.


Attachment 324073
does this data apply to all 928 MY's?
Old 12-28-2008, 11:23 PM
  #5  
Bill Ball
Under the Lift
Lifetime Rennlist
Member
 
Bill Ball's Avatar
 
Join Date: Mar 2002
Location: Buckeye, AZ
Posts: 18,647
Received 49 Likes on 36 Posts
Default

Unequal rear toe can cause pull to one side. They should be able to get them closer than they did.

Unequal caster can do the same thing. So, say, in the alignment you got, if the left side was as low as it could go at 3.58, the other side should have been set the same, not lower. It's common in these cars not to be able to get below 4 and that's fine.

Your camber is higher than spec. That may be as low as they could get it due to compression of the upper control arm bushings over the years. Or it could be due to ride height being set too low.
Old 12-30-2008, 09:05 AM
  #6  
Earl Gillstrom
Addict
Rennlist Member

 
Earl Gillstrom's Avatar
 
Join Date: Jul 2002
Location: Glen Mills, PA
Posts: 510
Likes: 0
Received 1 Like on 1 Post
Default

Michael,

All previous replies are excellent. You might go to my web site and print all of the wheel alignment section.
Also read all of the "miscellaneous ramblings"

http://members.rennlist.com/captearlg/
Old 12-30-2008, 06:46 PM
  #7  
jcorenman
Rennlist Member
 
jcorenman's Avatar
 
Join Date: Jan 2008
Location: Friday Harbor, WA
Posts: 4,062
Received 317 Likes on 153 Posts
Default

Originally Posted by 6mil928
does this data apply to all 928 MY's?
I believe that it does, that page in the WSM superceded previous versions. Be sure to read Earl's pages even if you have a shop do it, his info on DIY alignment is really good.

Old 01-04-2009, 04:55 PM
  #8  
6mil928
Race Car
 
6mil928's Avatar
 
Join Date: Sep 2007
Location: No where Oklahoma AKA "The Dust Bowl" In The Arm pit Of Hell
Posts: 3,663
Likes: 0
Received 0 Likes on 0 Posts
Default

I did excellent info.



Quick Reply: Wheel Alignment



All times are GMT -3. The time now is 07:10 PM.