Brake Trouble?

[Aryeh Levy]

When I bought my 1998 k3500, i took it to the shop to get it maryland inspected. they replaced the hydroboost unit.

My problem is that when i try to brake sometimes, it'll brake a little bit, then a second or two later (not slowing much at all) the full force of braking comes in. To effectively brake the truck, it often ends up near the bottom.

feels like (to my novice mind) that thir is an air bubble in one of the lines, and it takes some time to dissolve in the fluid...


Did the mechanic forget to bleed the brakes or something? Do i need to flush out the Power Steering Fluid and the Brake Fluid?
Bleed the brakes?

One of you more experiences mechanics should tell me what to do...

Also, for 1998, what type of fluids do i need to do what i need to do.

[HowieE]

Yes you may have a problem but in general GM never installed barkes that work on that vintage truck. I the 7 years I have had my 97 2500 Sub I have never had rear barkes that worked on that truck. If fact today I check the condition of one of the rear axel seals that has been giving me a problem only to find the whole backer plate and shoes were soaked with grease from another failed seal. Never noticed it in the braking, thus my comment the rears never worked anyway.
So have the system checkout but don't expect much.

[JohnC]

Originally posted by Aryeh Levy:
One of you more experiences mechanics should tell me what to do...
Take it back. Make them fix it!

[Aryeh Levy]

I had all this service done in february - I only now notice and understand enough to say that its a little wierd. Is it too long to say somethin?

[TurboDiverArt]

Further description of the problem needed. When you are stopping normally is it OK? Is it only a problem when you stab on the brakes? The rear shoes as stated above only really work if you continually adjust them. I try and check/readjust them every 2500 miles at oil changes.

I had posted a while ago about how my brakes worked. I noticed that when I stab the brakes hard it either gets hard for 1/2 second or goes mostly to the floor and then grabs. 1-2 seconds seems like a long time and would be a problem. If it's only really 1/2 second then I would say that

[NH2112]

I'd say to go ahead and bleed the master cylinder and brakes, then adjust the rear brakes. You want to have a light drag from the brakes when you turn the drum. But, I have to say that I've owned or driven a LOT of hydroboost-equipped vehicles and not one of them "normally" had a delay when braking. You may need to bleed the air from the p/s system, your master cylinder could have air in it or be going bad, etc. But other than the occasional leak, hydroboost systems are pretty much bulletproof.

[HammerWerf]

Arveh,

Quote:
"My problem is that when i try to brake sometimes, it'll brake a little bit, then a second or two later (not slowing much at all) the full force of braking comes in."

This sounds like a rather agressive brake pad compound ie: high Metallic brake pads. Some of them have to be warmed up for them to have max braking ability.

I have found that the front floating calipers stop floating after a time (length undefined). The sliding surfaces fill with brake dust, and other gunk, preventing the outer pad from being pulled against the disc. Then you get one disc brake. My wife complained of a metallic grinding sound. I looked in the wear windows on the caliper, and saw the outer looked fine. The inner one looked OK, but it was hard to tell. When I checked it out, I found the outer pad about 1/2 used, and the inner one making groves in the disc from the bonding compound. Other side was the same way. After cleaning all the caliper surfaces, braking has improved greatly. I can almost stop like we want to. I saw a post here that the poster said that every spring he pulled the brakes apart and cleaned them. He apparently was having few problems getting his rig to stop. And to think I pulled a 33 ft trailer through No. Cal and Oregon on those partially operating front brakes. :eek:

My rear brakes do not indicate that they are not working, so I can't comment on them.

I'm with Phil on the HydroBoost. The may leak, but I've never noticed a delay in braking action.

IF you have air in your lines, the RED brake light will come on due to imballance in the line pressures.

HammerWerf

[Aryeh Levy]

Yeah. When I'm on the highway, and Someone cuts in front of me, i slam on the brakes, and it goes to the floor, then 1/2 second it firms up a lot.

[jspringator]

I replaced my brake fluid and it helped a lot.