jdustu

iTrader: (2)

I won't go into everything here, but ever since I put a moser 9" under my car last spring I've been fighting wheel hop. I'm finally getting "professional" to look at it this week, but this last thing is bugging me.

He looked at the car last week, but didn't want to mess with it because the driveshaft was too short(the guy I bought it from said it would work, obviously he was wrong), so I had a custom one made. But while he looked at it he noticed the wheel base was way off, by 3/4". I had always measured from the fenderlip to the wheel, which wasn't too smart. So I looked up the stock wheelbase and set it to that(right around 101 1/8"). But I can take it for a ride around the block, and when I come back it's off again. This last time I did it, it went from 101 1/8" on both sides to 101 3/" on the driver side and 100 7/8" on the passenger side. And the control arms are still locked tight.

What could be pulling the rear ****-eyed? It's got to be the torque arm, right? Any ideas?

-Josh

Manic Mechanic

iTrader: (3)

Do you mean the control arms are adjustable and locked tight or that the control arms have been retorqued at both ends and are still tight in thier body mounts? If it was the torque arm (such as a front link that isn't vertical) it should effect both sides the same. You describe it as the rear is crooked, that would be control arm related. They need to be torqued down to factory specs to stay put.

Vernon

socmguy

iTrader: (18)

yeah, not sure what you meant. adjustable control arms or a panhard rod right?

02Z28LS1

iTrader: (2)

if the torque arm is a stock-style sliding type (the front can slide forward/backward), then it's not the torque arm. and even if it is a tunnel-mounted type, as Manic Mechanic stated, it would likely be off by the same amount on both sides. my bet thought, is that it's in no way related to the T/A.

i'm assuming that your LCA's are adjustable, or you wouldn't really be able to change the wheelbase. if that's the case, then you need to check the threads on the LCA adjusters to make sure they're not stripped, causing it to change their length a bit when a load is placed on them.

if so, you will need to either replace the rod ends (or the threaded adjuster, if it's the BMR-type adjuster that's in the center of the LCA), or replace the entire LCA, if the threads in the LCA's themselves are stripped.

it is also possible, however, that the holes that your LCA bolts go through have somehow been wallowed out, so check for that as well.

leadfoot4

iTrader: (1)

You could also get the car on a 4 wheel alignment rack, and using the rear gauges, set the wheel base so the rear axle is in parallel with the front wheels. This would be more accurate than a tape measure. In fact, you could also set the panhard bar, if you have an adjustable unit. Then drive it around, and recheck it, assuming that the alignment guy has the time .....

jdustu

iTrader: (2)

It's at a shop right now, so the alignment will be checked more accurately.

The control arms are locked tight both in adjustment and where they mount. There is no movement in them.

The wheel base is being effected the same distance: it's moving 1/4" foward on one side and 1/4" back on the other. So if the crossmember(which the ta mounts to) is slightly cocked, is it conceivable that it's cocking the rear end with it? I think this is where the problem is, at this point I hope it is because I'm running out of patience

leadfoot4

iTrader: (1)

On the OE torque arm, as well as most of the aftermarket units, there's a "sliding" sort of bushing at the nose of the arm, so the arm can shift to and fro, as the rear suspension goes through its travel. Is your torque arm one of those that has a "pivot" style bushing at the nose?

If so, then I would guess that it's conceivable that if the torque arm isn't truly perpendicular to the rear axle, and if the LCAs have rod ends that allow lateral movement, that could cause a slight wheelbase shift. But how would you notice it when the car is stationary? I could see it happening as you accelerate, or go over dips and rises in the road, as the rear axle pivots around the nose of the torque arm, but then the rear end must really be fighting the panhard bar...