The 250k-mile Brakes preventative maintenance

[zaid3ssaf]

The 02 Bravada has officially 250,000 miles on the clock. Brake Pads and rotor replaced 10,000 miles ago along with a full flush (MC reservoir fluid replaced and all 4 lines bled until clean fluid come through). Everything works fine .... sort of

I know our platform has soft/long brake pedal feel and I gave up on chasing it. With engine off, the brake pedal is rock hard. But when running (not moving), I can push the pedal 1/2 the way to the floor. Last week the pedal softened even more and now travels 3/4 to the floor --- which got me worried--- The truck still stops,; If I push the pedal 1/2 way while moving, It will throw me out of the window.

My problem is the same exact one as https://gmtnation.com/forums/threads/brake-pedal-feels-soft-04-tb-lt-i6-4-2-4x4.15160/

This winter, I exercised the crap out of the ABS module so I don't think there could be air trapped in it. So now I am looking to do full brake service. What should I replace? My list has the Master Cylinder and the 4 rubber lines. Should I do the booster as well (vacuum leak)? calipers? booster check valve? I don't have leaks and the calipers and pins move freely.

 

[Mooseman]

I'd replace the MC, the hoses may have stretched so that could be worthwhile, do a good flush and get a Tech 2 or similar scanner able to do the proper ABS bleed procedure because I'm not entirely convinced just slamming the brakes and activating the ABS does it. I wouldn't bother with the booster unless it has issues.

 

[zaid3ssaf]

Thank you Mooseman, I will start with the master cylinder. The rubber hoses look fine on the outside but I don't want to risk 20 years worth of exposure to the elements.

 

[JerryIrons]

I would consider pinching off the rubber hoses one at a time, and pushing on the brake pedal to see if you can isolate the problem. Not sure how the Bravado system works, but in my trailblazer out of the master cylinder are two brake lines to the abs controller, one is for the front and one for the rear.

You can also cap off the master cylinder with line ends and push on the pedal to see what happens as well.

Since you are going to replace this stuff why not try it out. Even a small leak at a bleeder screw can let some air in = annoying soft brakes.

 

[Ilikemy3s]

MY 04 SWB TB has 241k Miles and I am wondering about the same issue .. especially witht he rubber lines at the wheels.

 

[zaid3ssaf]

Is it a good idea to use thread sealant on the brake bleeder screw? I will experiment with capping the lines like JerryIrons suggested.

 

[Mooseman]

I use Teflon tape.