Ride feels bumpy during braking

[theholycow]

This is in Bessie, my 2002 GMC Sierra 4x4 with 4 wheel disc brakes and 184,000 miles.

When braking, I get a minor bumpy feeling. I've never felt it before. I don't feel it in the brake pedal, I feel it in the seat. It's like I'm running over perfectly spaced bumps in the road, or like there's something stuck to my tire. It only happens while braking. A faint bump noise accompanies the feel.

It is not ABS engaging; I'm intimately familiar with my truck's ABS and that's not it. It does not feel like warped rotors; it's very well defined, on-off-on instead of fading in and out (hence "bumpy" not "lumpy").

I looked at my pads and rotors, they look good. There's no flat spots on the tires (and I'd expect that to feel the same whether braking or not).

[GasSavers_RoadWarrior]

Maybe there's a stiff spot on a shock or strut, due to rust or something, bounce on it hard, see if it seems catchy. Would show up due to weight transfer.

[theholycow]

I forgot to mention, it's matched to speed, as if it's happening once per revolution...but I'll still have to check the suspension as you said.

[GasSavers_RoadWarrior]

Did you check the insides of the tires for bulges?

[theholycow]

No, and I forgot to check the inside brake pads too.

[Jay2TheRescue]

I would take a closer look at the rotors and shocks. How many miles do you have on the shocks?

[GasSavers_RoadWarrior]

Another thing, tie rod ends, Wile-Es had been a smidgin loose, had new ones in hand, felt it vibrating today, gotta get 'em in real soon now.

[theholycow]

Originally Posted by Jay2TheRescue

I would take a closer look at the rotors and shocks. How many miles do you have on the shocks?

184,000

[Jay2TheRescue]

I'd replace the shocks first. They're way overdue anyway. Large vehicles usually ride nice, even with bad shocks - so you may not experience a bad ride. Even my Buick will give a cloud-like ride with bad shocks. Oh, and because they've been in there so long, go ahead and go to Sears and get the lifetime shocks + installation. I bought that on my Buick, at the time installation + lifetime warranty was only an extra $9/shock. Well worth it. I've gotten several sets of free shocks over the years, and if the nuts holding them are seized (which is likely if you have over 180,000 miles on them) its worth it to not have to climb under there.

-Jay

[theholycow]

Actually, my ride is significantly stiffer than it used to be. I attributed that to general wear on all the suspension, and specifically to tired springs, but maybe it's shocks.

If that's the case I'll just continue to defer that bit of maintenance. The symptom doesn't bother me except that I fear it could be a sign of something that will become more expensive to fix if I ignore it.