Using a hydraulic floor jack
10-22-2008, 12:17 PM
#94
6th Gear Member
Join Date: Feb 2007
Location: state of confusion
Posts: 7,635
What the bending that people are somewhat concerned about is trying to do is make the rear wheel camber less negative/go positive/go more positive. Stick axles are not at all guaranteed to have either zero camber or zero toe, and what these alignment parameters happen to be does affect the car's handling.
In this case, the axle bending from lifting by the pumpkin is in the direction of less negative/more positive camber. It won't be enough to see, but might be enough to measure with a digital angle-finder. More things than the length of time under improper lifting are involved, so I would not be the one to make any guarantees that the cambers would precisely return to their previous values when the improper lifting condition is removed. Translation: if it does not all come back, the rear of the car will have a little less lateral grip available and will be slightly more apt to oversteer (something that kind of scares the OEM's, courtesy of guys like Ralph Nader and faceless ambulance-chasers)
I doubt that many people outside of road racers, circle track racers, autocrossers, suspension engineers, and the better alignment techs ever consider stick axle alignment measurements other than pinion angle and maybe thrust angle, mostly because there isn't much that can be easily or economically done to change it. How many people here have ever even checked for themselves to see where their rear wheel cambers & toes are really at?
(Other than to remove an axle entirely or replace leaf spring shackles I don't think I've lifted the rear of a car by the pumpkin a dozen times in my whole life.)
The car in the link below has about -0.5° camber
(both sides) and about the same amount of toe-in (not so nice). It may look slightly +camber in the picture, partly due to lateral tire distortion and partly because the axle itself rolls a degree or more in a hard corner (tire compression). But it really is static negative.
https://mustangforums.com/forum/albu...&pictureid=834
Norm
In this case, the axle bending from lifting by the pumpkin is in the direction of less negative/more positive camber. It won't be enough to see, but might be enough to measure with a digital angle-finder. More things than the length of time under improper lifting are involved, so I would not be the one to make any guarantees that the cambers would precisely return to their previous values when the improper lifting condition is removed. Translation: if it does not all come back, the rear of the car will have a little less lateral grip available and will be slightly more apt to oversteer (something that kind of scares the OEM's, courtesy of guys like Ralph Nader and faceless ambulance-chasers)
I doubt that many people outside of road racers, circle track racers, autocrossers, suspension engineers, and the better alignment techs ever consider stick axle alignment measurements other than pinion angle and maybe thrust angle, mostly because there isn't much that can be easily or economically done to change it. How many people here have ever even checked for themselves to see where their rear wheel cambers & toes are really at?
(Other than to remove an axle entirely or replace leaf spring shackles I don't think I've lifted the rear of a car by the pumpkin a dozen times in my whole life.)
The car in the link below has about -0.5° camber
(both sides) and about the same amount of toe-in (not so nice). It may look slightly +camber in the picture, partly due to lateral tire distortion and partly because the axle itself rolls a degree or more in a hard corner (tire compression). But it really is static negative.https://mustangforums.com/forum/albu...&pictureid=834
Norm
Last edited by Norm Peterson; 10-22-2008 at 12:21 PM.
10-22-2008, 12:52 PM
#95
2nd Gear Member
Join Date: Apr 2007
Location: IL
Posts: 413
If you don't want to jack it by the rear pumpkin, jack it by the axle tube out by the end. I don't think there's ever been any argument about jacking it there although the way this thread goes it could begin now too... I've jacked cars up from all sorts of places over the years and never damaged one from anywhere.... If you're that unsure, get a set of ramps....
Thread
Thread Starter
Forum
Replies
Last Post
