[wilky]

I have a 2003 Silverado 1500 4x4 extended cab 5.3L with 250,000 miles on it. I bought the truck new and it has been my “farm truck” for the last couple of years. About a year ago, I got the “service brake system” message and the brake pedal started going to the floor along with a significant drop in braking power. Based on skid marks from braking on muddy ground, it appeared that only the front brakes were working and were also locking up and skidding. The problem persisted all year (with the exception of one week in the summer when everything worked as it should) and now it appears that only one wheel is working. I don’t drive this truck much and it never gets off the farm. I have never had any brake work done except for pads and that has been quite a while ago. Fluid is full. My question is where should I start? ABS? I know lines are an issue on some Silverados? Master Cylinder? One others issue that may or may not be related is that something is slowly draining my battery.

Thanks!

 

[Zach Smith]

Guess, some easy checks...check for leaks, rear wheel cylinders... Lines and such, check that fluid is making it to all 4 corners, via the bleeders...check that there is pressure at all 4 corners (if by yourself, pump pedal a few times, then use a pry bar or something against the seat to hold pedal down) do this once for each corner. If no pressure on rear, you have a spot to start chasing from and so on...could be a seized caliper on front if both sides have pressure. Can also check for pressure at the master...can also look at back of master, is it wet? Is paint bubbled? Could pull master forward slightly and look for leaks...

 

[j cat]

pedal to floor no rear brakes front brakes lock up skidding ... this is the GM defective brake lines .. yes they rust out in a few years in the rust belt . should have been recall but NHTSA always gives GM the easy way out ,despite owners getting into accidents and reporting ..

so my guess is the brake line running along the frame rail next to the fuel tank is with a hole...

that is how it all begins then the lines behind the driver side front tire will blow ...
GM has a kit for your old truck about 110USD at dealership.. reason is it is a huge failure item .. good luck not a fun job ...

 

[RayVoy]

The guys could be right; but if the MC is full, probably not leaking.

I'd pull the ABS fuse just to see if ABS is the problem.

 

[j cat]

The guys could be right; but if the MC is full, probably not leaking.

I'd pull the ABS fuse just to see if ABS is the problem.

when it happened to me the line had a very small leak it did not make any indication of a leak but it got air in the line and then the rear brakes do not work .. brake fluid was at the level..

when the front brake lines blow that was a mess ..no brakes ..

remember pedal to floor is leak or possible master cylinder or air in the master...
since the front brakes work then no master issue .. bleed rear brakes if air come out very possible the same failure I and others have had ..

GM ran these brake lines in areas that is not accessible and no visual inspections to be made.. PITA to do..

 

[RayVoy]

Your right J cat, air could be pulled into the system.

Wet spots should be easy to spot.

The thing that bothers me is the system going back to "normal" the next day. I had a S10 that would do that, the pedal would all of a sudden go to the floor. It would only happen when a couple (maybe all four) wheels were on a slippery surface and I was almost stopped. At about 10 mph, no brakes, just like the line broke.

I pulled the ABS fuse and never had the problem again.

I'm not saying this is the OP's problem, just suggesting to eliminate the ABS

 

[xPosTech]

I had the same symptoms with my S15 Jimmy. The first time it happened I quickly checked my 6; I thought I had been rearended. The next time I heard the ABS pump come on. Could never find the reason so I too pulled the fuse except for inspection.

Ted

 

[j cat]

the ABS is a tricky little devil on these models ...ABS solenoids can stick when those steel screws rust out in the aluminum valve body.. get contaminated ..

 

[RayVoy]

I think it was the design of the unit GM was using at the time, mine was only a couple of years old when I bought it and I only had it for a few months when I pulled the fuse.

Over the years, I've heard of a lot of people, like Ted, who had this problem on the S10/15 trucks

 

[j cat]

pull the fuse is the safe method until fixed ...
after I dd all this ABS work brake lines/ abs ECPBM and the hub sensor work ABS works better than new .. not all that often the brakes pulsate with the ABS activation..

toyota no abs ,,, brakes lock up.. actually it has a brake fluid pump electric.. I push on the brake a little too hard the pump turns on and it does scare me as it is the opposite of the GM truck..

 

[RayVoy]

WOW, didn't know that, now need to experience, haha

 

[wilky]

Folks, thanks for all the replies and advice. I’ll let you know what I find out