Wanders when braking

[skyhigh4by]

Just to cover the bases its a 82 K30 w/ 8" BDS springs, ORD shackles, DIY4x shackle flip stock rear springs. The axle is a D60 with crossover/histeer and basically everything from tie rods, wheels bearings, kingpins, steering box, and leaf spring bushings are all new.

When I apply heavy brakes the steering wheel often pulls. The strange thing is that it's unpredictable how much it will pull and even stranger which direction it will pull. I basically just have to be prepared for the truck to start wandering when I apply brakes. Any ideas?

 

[skyhigh4by]

Tires are 37.5" nitto mud grapplers in good shape with about 60% tread

 

[Smokinthehippies]

I'm betting your tires are just following the road and it's more noticeable when your hard under braking.

 

[skyhigh4by]

Thats understandable considering they are 15.5" wide BUT Ive had them since new and they never used to do it and I driving all the same roads/ruts as before. The wandering is a newish thing.

All the steering stuff has really low miles and I regularly check everything over, the thing confuses me is that it drives straight as an arrow until brakes are applied.

 

[rebelgregory]

Have you done anything that would change caster? Or anything that would give the axle more leverage to wrap(thus changing caster) such as zero rates etc?

 

[skyhigh4by]

I recently added 6* shims to the rear but the front is unchanged since built

 

[Greg72]

Just to cover the bases its a 82 K30 w/ 8" BDS springs, ORD shackles, DIY4x shackle flip stock rear springs. The axle is a D60 with crossover/histeer and basically everything from tie rods, wheels bearings, kingpins, steering box, and leaf spring bushings are all new.

When I apply heavy brakes the steering wheel often pulls. The strange thing is that it's unpredictable how much it will pull and even stranger which direction it will pull. I basically just have to be prepared for the truck to start wandering when I apply brakes. Any ideas?

Are you still running the stock push-pull steering setup?

I wonder if you are just getting a "bump steer" effect as the front springs compress under hard braking... 8" lift without crossover steering is definitely NOT the ideal setup.


-G

 

[skyhigh4by]

Northwest Fab crossover histeer but I'm thinking your probably on to something with the bump steer cause the wheel does jerk when I hit bigger bumps

 

[Burbdood 74]

What kind of shape are your brakes and brake rotors in? My driver side brake rotor is shot to hell and when I hit the brakes, my Sub veers to the right because the brakes are grabbing good on the right side but not so good on the left.

 

[Blue85]

When I apply heavy brakes the steering wheel often pulls. The strange thing is that it's unpredictable how much it will pull and even stranger which direction it will pull. I basically just have to be prepared for the truck to start wandering when I apply brakes. Any ideas?

Have you been through the caliper slides and bushings to make sure they are all sliding freely? It could also be a bad caliper. If the seal is hanging up on some rust in the bore or something if might not always extend and retract the same way. Also if it's leaking fluid that would certainly make it less consistent.

But the way you describe it, the brakes aren't just pulling one way or the other, but the whole thing starts wandering around. That really sounds like something is loose. Maybe time to start checking the "non-steering" parts like spring bushings, tight U-bolts, wheel bearing preload, etc.

 

[Fred_M1010]

If a TRE is worn, and it's close to zero toe, it will result in toe out when braking, which will cause problems like you described.

 

[ashman]

I have much the same problem. I was told my spring bushings are shot and that might be causing it.

If a TRE is worn, and it's close to zero toe, it will result in toe out when braking, which will cause problems like you described.

Hmmm, I might need to check into that myself.