Brakes or front end?

[CoryB]

Need some help on this one please...

1998 TJ SE
3" Rusty's lift with stock control arms
32" GY MT/Rs
73K miles (more or less)

The problem started a while back but seems to be getting worse. The lift and tires have been on for much longer than the problem has existed.

When I stop hard, like an emergency stop, the Jeep will first pull to one side, then pull to the other, so that I'm sawing the steering wheel back and forth trying to keep it in the lane where I started.

Easy stops only gets a mild pull to the left that I think is a semi-functional right rear wheel cylinder.

The front end seems tight - no visible play in any TRE, ball joint, steering box, etc. But it could be an excuse to upgrade to a RE long arm kit anyway. Front end hasn't been professionally aligned in several years, but backyard alignment looks good.

The tires are rotated every 3000 miles when the oil is changed - no strange wear patterns on them.

Parts replaced so far:
Rebuilt front calipers
Front brake hoses
Front brake pads
Front rotors
Rear shoes
Rear brake hardware
Rear drums

So all that's really left of the braking system are the rear wheel cylinders, rear brake hose, master cylinder and proportioning valve.

Is there an easy way to completely disable the rear brakes to see if that wheel cylinder is the cause?

If the wheel cylinder is the problem, why does the Jeep zigzag under braking? I could understand it pulling to one side, but not zigzagging.

If it's not the rear wheel cylinder, where else should I check?

Thanks for any help.

[Robert J. Yates]

Have you checked the tightness of the front trackbar and the control arms?

Also, how do you know the ball joints are good? Did you jack the rig up and test each side?

[KJP98TJ]

[out on a limb]

would nose dive contribute to this, given "stock" track bar and draglink angles/lengths?

[CoryB]

Originally posted by Robert J. Yates
Have you checked the tightness of the front trackbar and the control arms?

Also, how do you know the ball joints are good? Did you jack the rig up and test each side?

Thanks for the suggestions.

Yes, I've tightened the trackbar as tight as I can get it with a breaker bar and all of the control arm nuts have been retorqued.

I've checked the ball joints by jacking up the front tire and putting a long prybar under it and lifting to see if there's any play (VA state safety inspection procedure.) If you know another way I'll be glad to try that also.

[CoryB]

Originally posted by KJP98TJ
[out on a limb]

would nose dive contribute to this, given "stock" track bar and draglink angles/lengths?

If it had happened immediately after the lift, I'd be inclined to agree. But the lift has been on for about 3 years total and the problem just started a few months ago.

Also, my wife's TJ has the same lift, tires, etc., but doesn't have the brake zigzag problem.

I do have about 3 times more mileage on mine though.

[Robert J. Yates]

Something is wore out and its a matter of you finding it. Have you changed anything lately which made the problem appear or become worse? I find that I usually have to backtrack on either of my vehicles and go back to what I changed and elimiante all of that first.