'97 1/2 ton Chevy 4X4 Brakes!

Mr.Rivera100 · #1 11-29-2008, 07:08 PM

My brakes are locking up before I come to a stop. I replaced my master cylinder, and that did not fix the problem. What could cause my brakes to malfunction like this? Can someone help me out?

j cAT · #2 11-29-2008, 07:16 PM

Quote:

Originally Posted by Mr.Rivera100

My brakes are locking up before I come to a stop. I replaced my master cylinder, and that did not fix the problem. What could cause my brakes to malfunction like this? Can someone help me out?

what brakes,, front / rear? do you have drums in rear?

have you had any work done to brakes?

Mr.Rivera100 · #3 11-29-2008, 07:17 PM

I removed all wheels and inspected all components, and everything appears ok. I'm hoping its not the proportioning valve?!

Mr.Rivera100 · #4 11-29-2008, 07:24 PM

I replaced the front pads a month ago, but this "locking up problem" just started last week.

horse482 · #5 11-30-2008, 12:28 AM

Could be an abs problem. Is it the front or rear wheels that are locking up or is it just one? Does your truck have rear wheel abs or 4 wheel abs?

Reflash · #6 11-30-2008, 10:43 AM

Does the brake pedal ~pulse~ when the condition is present? If so, like what horse482 said...could be ABS related.

and most likely one of the front wheel speed sensors is causing it. Best way to pinpoint is to use a scan tool to snapshot the condition and then replay it using the plot function. If you don't have access to a scan tool, then a shop visit may be required.

j cAT · #7 11-30-2008, 10:58 AM

Once again what wheels are locking up? do you have drum rear brakes?

Reflash · #8 11-30-2008, 11:02 AM

FWIW...only drum brakes were offered in 97 for the rear

j cAT · #9 11-30-2008, 11:09 AM

Quote:

Originally Posted by Reflash

FWIW...only drum brakes were offered in 97 for the rear

well if he does have rear drums...the most comon cause if the rear brake locks up is gear oil on the drum...this will cause his problem for sure..also with the drum brakes it is very common for the front brakes to do ALL the braking as the rear shoes are never adjusted...this inbalence will cause the wheels to lock up...

after the new brake pads took a set ,, they may be creating a very large brake rate compared to the rear...

Reflash · #10 11-30-2008, 11:17 AM

Good point jcat, I overlooked the grease possibilty. However, the oiled drum is not the one locking up, the one that is dry would be the culprit that locked up.

I still believe his problem is ABS induced. If the OP comes back and answers a couple questions, we might be able to help

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