87 k10 brake shake

[89k5350]

so this past 2 weeks of driving my 87 stepside it seems like the brakes are pulsating more and more. it is to the point where when I touch the brakes at about 30-40 the whole truck shakes really bad then goes away but I can feel the brake pedal going in out as im on the brakes. I assumed the rotors and just did a brief look and feel of them and they look fine and smooth, they are only about year and a half two years old. and I am currently running on only front brakes. so if the rotors aren't warped what else would make the truck shake wile im hitting the brakes?

 

[rampage]

Your rotors are warped, get them turned. Also, you can warp the rotors by not tightening the lug nuts in a star pattern or by over tightening them like what they do at tire shops.

 

[sweetk30]

if pulsation and movment in steering wheel its in the front .

if pulse and vibe in pedal and up threw floor and seat its in the rear .

but this is only correct 95% of the time . some fool you .

I know from watching you here you just did rear work . did you put the short/thin brake shoe to the front and the long/thick shoe to the back when you had it all apart ? this can make a vibe .

how was the axle seals ? any oil on the shoes can cause a vibe also .

 

[rampage]

I doubt it's the rears since he says he's only running on the fronts. I'm assuming the rear line has been blocked off. So if only the fronts are doing all the work then they might be overheating causing them to warp, in which case they will likely warp again once they get turned.

 

[4X4HIGH]

It only takes .006" of runout to get a brake pulsation in the pedal. Like was already said you need to have the rotors machined and get the back brakes working again because without them the fronts are doing waaay more work than they should and the rotors will warp again as also was already mentioned.

 

[blazer74]

X2 and correct tightening and torque specially if the rotors are hot as was mentioned.

 

[4xcrazy]

So if only the fronts are doing all the work then they might be overheating causing them to warp, in which case they will likely warp again once they get turned.

I was going to mention this too, overworking those rotors, lots of heat. I ran that way for a short time when I was trying to figure out why I lost rear brakes.

 

[89k5350]

this is more than a pulsation this thing SHAKES bad like stuff in the bed jumping up cause of the shake. I jacked the truck up and I cant describe to you how much play was in the wheel up down and left right it was about 5-6 inches of play all the way around. outer side of rotor was still like brand new. so I took 4wd hub all apart and the back wheel bearing nut was finger loose and the hub was filled with metal shavings. after I pulled hub/ rotor off axle the back side of rotor was shot. I think the wheel bearing nut was so loose that the rotor was rubbing on backing plate causing the metal shavings. soo times for new rotor/ pads and wheel bearing

 

[black dawg]

I just worked on a similar truck, that had very poor rear brake bias, you could smell the fronts pretty much any time you stopped, and was very dangerous. I cant imagine that yours would stop any better.

 

[2_wacko]

I had a similar problem turned out to be a loose caliper bolt.

 

[AR_K5]

I know you found the problem but another cause of warped rotors is getting the hot going down a hill or something, right before you drive into water.

Just throwing it out there as something to keep in mind.
Hot brakes + water = warped rotors

 

[Stomis]

Its quite the accomplishment to warp those frigging rotors. Theyre thick as a mother ****er. Only time I would except to get runout in them is from pressing them on a hub and not cutting them true to the hub.

 

[AR_K5]

They aren't that thick, look at the outside edge, rotors are hollow and have vents to help dissipate heat.

 

[diesel4me]

I've seen rotors that still look nice and meaty have cracks in the cooling fin area in the center,which lets the disc surface flex in and out and eventually crack off completely...not unusual to see them rust away to nothing at the fins inside too--ones on my truck are getting kinda scary looking there,yet the disc surface looks thick as new and no scoring--no pulsation or warpage yet,but I bet it wont be long..