Steering wheel shake from braking

[leonard_nemoy]

So I noticed my steering wheel has developed a shake when I brake hard on steep hills only. Ie coming down canyons and such. It feels like the shake you get in the steering wheel when your tires are out of balance but my tires are definitely balanced and I only get the shake when I am braking hard. I feel like it could be warped rotors but I only feel the shake in the steering, not in the floor, seat, or pedals. I got a new stabilizer, new steering components, new shocks, 3 degrees of castor, and new control arm bushings within the last year. Any ideas on what I should check? Could this be from warped rotors?

 

[Outsane]

Usually from brake material deposited on rotors.

I try to use low gears to slow down the rig instead of brakes as much as possible. I still get this kind of behavior.

 

[BILT4ME]

Do another bedding of the brakes and see if it fixes it.

Yes, warped rotors, contaminated pads, loose wheel bearings, loose steering arm nuts, worn TRE.

 

[ppc]

Issues originating on the front axle tend to show through the steering wheel. Rear axle issues tend to show through the body (floor, seats.

If you had warped rotors it would be more pronounced in the steering wheel as there is a mechanical coupling but will be much less pronounced through the brake pedal as the coupling is via fluid.

Going down hills and canyons might be indicative of overuse of the brakes causing overheating of the front brakes where most of the braking takes place. You really didn't supply enough detail on the conditions to provide a better suggestion. I would suggest downshifting to a lower gear for more engine braking letting your brakes cool.

 

[greentruck]

Very first thing to do is to check your air pressure in that tire. If OK, then pursue the myriad of other possibilities. If underinflated, add air and test drive to see how much difference it made. Then figure out whether the tire has an issue or just seasonal loss of air pressure, etc that inflation cures.

Just found a rusty nail embedded in one of my BFGs that was small but had PSI down to 20 over the course of the few weeks since last checked.

 

[mudgudgeon]

I'll put money on loose wheel bearings.
Have had it a couple of times after following the FSM wheel bearing preload procedure

 

[leonard_nemoy]

So the tires are fine, balanced correctly and the air pressure is right where I want it. I know how to downshift going down steep canyons but sometimes one still has to use the brakes to slow down for a pedestrian, animal, corner, or other vehicle etc. I had the knuckles rebuilt about a year ago (12,000 miles) so I don't think it is wheel bearings, I figure this would have happened sooner if it was bearings. The tie rods along with the rest of the steering components are new heavy duty replacements from manafre so I dont think those are the issue. But the rotors are 5 years old and have had a few sets of pads thrown at them over the last 100,000 miles so I am thinking brakes are the issue here. I was just under the impression brake shimmy/pulse was felt through the floor and pedals instead of the steering wheel, but every vehicle is different, and it sounds like 80's do present brake shake through the steering wheel so I am going to freshen up the brakes with new rotors, pads, and calipers if needed. Thanks for the input. All my other vehicles would have a pulse in the floor and pedals when my rotors were bad so I am glad I got this forum to school me on the nuisances of the 80 series.

 

[bwesty]

Could it be a caliper sticking on one side or the other? Are your caliper mounting bolts all torqued properly?

 

[LINUS]

If the tires have even wear / been on long enough to reflect issues - then yep, rotors & pads seems probable.

If you have some squirm/tread cupping, then I’d look at my bearing torque, esp if tires are much of anything bigger than the stock ~31’s.

 

[mudgudgeon]

My experience has been wheel shimmy / steering wheel shake has been the first indicator of loose wheel bearing preload.
It has showed up as a shake in the steering wheel, and pulse through the brake pedal when washing off a little speed come down a steep hill, or when slowing down coming into a stop light when already traveling at relatively low speed. Say slowing from 25mph, to zero.
Full hard braking doesn't show it up.

YMMV but its a consistent indicator of loose bearings in my experience.

Easy to check. Jack front wheel of the ground, check for any play at all rocking the wheel from 6-12oclock

 

[WarDamnEagle]

My bet is on brake rotors; speaking from experience with our 80.