Gears & Axles Driveshafts | Rearends | Differentials | Gears | 12 Bolt | 9 Inch | Dana

Rearend alignment HELP!

Thread Tools
 
Search this Thread
 
Old 11-10-2003, 02:36 PM
  #1  
On The Tree
Thread Starter
iTrader: (4)
 
jpbgto's Avatar
 
Join Date: Oct 2003
Location: Panama City, FL
Posts: 160
Likes: 0
Received 0 Likes on 0 Posts
Default Rearend alignment HELP!

Recently on a trip home (from Fort Stewart to Panama City) my front tires got completely eaten up. So I figure it is my alignment and I take it in. The mechanics fix the front alignment, but show me on a computer print out that my rear is crooked. They said they had to drop the rear leaf springs drill some new holes and mount it back really tight to keep it straight. There hasn't been any irregular wear on the rear but I am still worried. Does this sound right? Is there any other solution? I have a 99 z28 m6 with 83,000 on it. Thanks for the help.
Old 11-10-2003, 03:27 PM
  #2  
TECH Fanatic
iTrader: (12)
 
NOBR8KSS's Avatar
 
Join Date: Mar 2002
Location: Greenville, SC
Posts: 1,126
Likes: 0
Received 0 Likes on 0 Posts

Default

My advise is take it to another shop. Leaf springs haven't been on f-bodies since the 70s.
We have coil springs and they have absolutely nothing to do with thrust angle.
If the thrust angle needs to be adjusted, you will need adjustable lower control arms. If the pinion angle is off, you will need and adjustable torque arm. An adjustable panhard rod wouldn't hurt either. I would get everything from www.lgmotorsports.com ... they are more expensive than most, but they are definitely worth it. Give them a call...they can answer all of your alignment questions.
Old 11-10-2003, 03:37 PM
  #3  
On The Tree
Thread Starter
iTrader: (4)
 
jpbgto's Avatar
 
Join Date: Oct 2003
Location: Panama City, FL
Posts: 160
Likes: 0
Received 0 Likes on 0 Posts
Default

Great thanks for the help. I knew something didn't sound right but the people who owned the shop go to my church. I will give them the benefit of the doubt maybe they haven't worked on this sort of problem. Thanks for the advise though, I was thinking the same thing about the panhard rod and torque arm. Thanks again.
Old 11-10-2003, 04:02 PM
  #4  
On The Tree
Thread Starter
iTrader: (4)
 
jpbgto's Avatar
 
Join Date: Oct 2003
Location: Panama City, FL
Posts: 160
Likes: 0
Received 0 Likes on 0 Posts
Default

Can you explain the difference between pinion and thrust angles?
Old 11-10-2003, 04:34 PM
  #5  
Moderator
iTrader: (11)
 
jimmyblue's Avatar
 
Join Date: Mar 2002
Location: East Central Florida
Posts: 12,605
Likes: 0
Received 6 Likes on 6 Posts

Default

Pinion angle is in the vertical plane (set by
the torque arm and axle height relative to
body).

Thrust angle is in the horizontal plane and
is set by the lower control arms & their
mounts.

To have a rear end misalignment you would
almost certainly have to have bent some
mount (or have adjustable LCAs, which
were misadjusted). On a stock rear it's
well nigh impossible to have a really bad
thrust alignment. Much lower odds than,
say, running across a weasel at a tire shop.

Rear end being out of line would result in
some "crabbing" but it's not going to chew
the fronts, unless your front align changes
a whole lot from a little off-axis steering.
In which case, you would chew the fronts
anyway every time you turn.
Old 11-10-2003, 09:34 PM
  #6  
wrencher
iTrader: (2)
 
wrencher's Avatar
 
Join Date: Aug 2002
Location: Chicagoland
Posts: 4,762
Likes: 0
Received 0 Likes on 0 Posts

Default

Originally Posted by seabassz28
The mechanics fix the front alignment, but show me on a computer print out that my rear is crooked. They said they had to drop the rear leaf springs drill some new holes and mount it back really tight to keep it straight.
Those guy where trying to drill something ,but not on your car!
Old 11-10-2003, 10:27 PM
  #7  
TECH Enthusiast
iTrader: (14)
 
skippytheloon's Avatar
 
Join Date: May 2003
Location: Nacogdoches, TX
Posts: 700
Likes: 0
Received 0 Likes on 0 Posts
Default

can you explain "crabbing" please?

leaf springs? they should at least know what those look like if they are mechanics, no matter how bad of a mechanic they are!
I'd like to know what they did to your car...
Old 11-11-2003, 12:56 PM
  #8  
On The Tree
Thread Starter
iTrader: (4)
 
jpbgto's Avatar
 
Join Date: Oct 2003
Location: Panama City, FL
Posts: 160
Likes: 0
Received 0 Likes on 0 Posts
Default

They fixed the front alignment, but I didn't let them touch the rear. Like I said something didn't seem right if the wheels cant to the left as looking from it from the rear would the lca's correct that? It kinda looks like this on the computer print out:
\------()------\
the \'s being the wheels and the () being the differential
Old 11-11-2003, 02:56 PM
  #9  
Moderator
iTrader: (11)
 
jimmyblue's Avatar
 
Join Date: Mar 2002
Location: East Central Florida
Posts: 12,605
Likes: 0
Received 6 Likes on 6 Posts

Default

[QUOTE=skippytheloon]can you explain "crabbing" please?
QUOTE]

If you ever saw one of those crabs on the beach, they
don't walk straight ahead, but sort of scuttle diagonally.
A car that's "crabbing" has its body pointing somewhere
other than the direction it's going. You see this a lot on
leaf-spring 4x4s that have bumped over too many rocks
and gotten the axle cocked. Funny when you do see it.
Old 11-11-2003, 09:03 PM
  #10  
wrencher
iTrader: (2)
 
wrencher's Avatar
 
Join Date: Aug 2002
Location: Chicagoland
Posts: 4,762
Likes: 0
Received 0 Likes on 0 Posts

Default

If you have the print out, Can you scan it?


Or at least post all the readings.
Old 11-11-2003, 09:33 PM
  #11  
8 SEC SLOPPY SHOT!!!
iTrader: (15)
 
tuff's Avatar
 
Join Date: Oct 2002
Location: lombard,IL
Posts: 1,862
Likes: 0
Received 0 Likes on 0 Posts

Default

What's the thrust angle number at. Did you hit something it would have to be big. Was the car ever in a wreck.
Old 11-12-2003, 11:08 AM
  #12  
On The Tree
Thread Starter
iTrader: (4)
 
jpbgto's Avatar
 
Join Date: Oct 2003
Location: Panama City, FL
Posts: 160
Likes: 0
Received 0 Likes on 0 Posts
Default

The left camber is -0.07 with a toe of -0.22
The right camber is -0.14 with a toe of 0.22
The thrust angle is -0.22




All times are GMT -5. The time now is 08:36 PM.