Brake Thump

beachrog · 02-03-2008, 10:22 AM

This may be one of those issues that's pretty vague until you pull the wheel off to look, but wanted to get some input on what to look for once I do.

I have a '97 K1500 350. When I first take the truck anywhere and I step on the brake I get a thump that you can sort of feel in the peddle. It's just one thump and then the brakes seem to still be working ok. I thought initially that some ice or something had just built up on the brakes but it is doing it every day now. First thing, it's a fairly noticeable thump. After you've driven even say a mile or so, it still thumps but not as loud and again only when you initially step on the brake.

Could this be a warped rotor or something wrong with the pad?

j cAT · 02-03-2008, 11:16 PM

Quote:

Originally Posted by beachrog

This may be one of those issues that's pretty vague until you pull the wheel off to look, but wanted to get some input on what to look for once I do.

I have a '97 K1500 350. When I first take the truck anywhere and I step on the brake I get a thump that you can sort of feel in the peddle. It's just one thump and then the brakes seem to still be working ok. I thought initially that some ice or something had just built up on the brakes but it is doing it every day now. First thing, it's a fairly noticeable thump. After you've driven even say a mile or so, it still thumps but not as loud and again only when you initially step on the brake.

Could this be a warped rotor or something wrong with the pad?

when you take wheels off and look at front brakes take a good look at ball joints.......possible control arm bushings as well......

G.A.S. · 02-03-2008, 11:25 PM

check wheel bearings along with all front end parts.
Also take a look at the calipers, make sure the slider kit is in good shape and the bolts are not loose.
See if a pad has come disconnected from the backing plate ( pad is glued to a metal plate ) I have seen them seperate.
Rear brakes out of adjustment, broken hold down springs ect.
theres a few more.
Have you icealated it to a certan tire or area?

beachrog · 02-04-2008, 06:57 AM

It would seem to be coming from the front on the driver's side. Which, last time I was in for an oil change, the guy said the upper ball joints didn't want to take any grease.

This morning it would thump fairly loud as I started down the road and hit the brake. As I got closer to work the thump would become more faint but again it would do it as I hit the brake. By the time I got to work, it wasn't thumping at all.

Being it's a '97 and judging from the corrosion we'd found in the radiator and the fact it has 206,000 miles on it, I'm assuming just about everything in the front end needs to be replaced. Judging on how it was taken care of by the previous owner, it's probably got all original parts on the front end....

However, these are some good places to look, I appreciate the input.

beachrog · 02-13-2008, 08:24 AM

This has continued to get interesting, it's gotten down right cold here lately and I've noticed that the initial thump as I press down on the brake pedal varies at times. There seems to be a point where I press down on the pedal and the thump is repetitive, but once I press the pedal beyond that point it quits. Everything seems to stop alright, no shimmy or anything. I'm wondering if this is something to do with the ABS although the thump thump that people report from ABS can't be as loud as what I'm hearing.

My wife has started complaining about a thump that she is hearing as well in her mini-van. They both have drum brakes on the rear and our last few vehicles have had disc brakes all around. Perhaps it has something to do with the drum brakes or adjusters....

j cAT · 02-13-2008, 10:27 AM

Quote:

Originally Posted by beachrog

This has continued to get interesting, it's gotten down right cold here lately and I've noticed that the initial thump as I press down on the brake pedal varies at times. There seems to be a point where I press down on the pedal and the thump is repetitive, but once I press the pedal beyond that point it quits. Everything seems to stop alright, no shimmy or anything. I'm wondering if this is something to do with the ABS although the thump thump that people report from ABS can't be as loud as what I'm hearing.

My wife has started complaining about a thump that she is hearing as well in her mini-van. They both have drum brakes on the rear and our last few vehicles have had disc brakes all around. Perhaps it has something to do with the drum brakes or adjusters....

if you are unwilling to remove tires and inspect brakes and front end steering componets I recommend you bring it to a recommended repair shop for inspection before you get into an accident........

beachrog · 02-13-2008, 11:40 AM

I wouldn't say I am unwilling. As I stated earlier, I'm just looking for ideas of what to look at, I don't want to pull the tire off and stand there saying, "Yup, that's a caliper."

BHolm · 02-17-2008, 09:20 PM

If you think it might be your ABS just pull the fuse for it and then drive see if the noise goes away. If the noise doesn't go away you know it wasn't the ABS. I would make sure the noise isn't ball joints, I had one let loose when I was younger before I learned about mechanics and let me tell you it is way cheaper to replace a ball joint before it brakes then after. Because of the collateral damage that usually goes along with a broken ball joint.

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