Brakes suck now!

rcfiddy1

Original poster
Member
Sep 13, 2012
23
Know people say our TBs brakes are a bit spongy but we have 3 TBs in the family and all 3 had great brake pedal feel till mine developed a problem. I had my pedal go to the floor so I started replacing pads, rotors, fluid, and master cylinder. The truck will stop but not in a predictable manner. I can not lock up the rear wheels or even get the ABS to take over, and if I hit the brakes 2 times in a second or 2 the second brake pedal feel is hard but truck does not want to stop. Any help would be appreciated.
 

AtlWrk

Member
Dec 6, 2011
674
Sounds like air and/or a leak.
I had those exact symptoms after I accidentally allowed air into the system during a brake job. Bleeding the lines correctly firmed everything right up. Was the master cylinder bled when it was replaced? Are there any signs of a leak anywhere in the system?
 

The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
My wife's Forester had a bad vacuum boost unit and caused those symptoms. I almost never hear of GMT360s having bad boost units, though.
 

Magyver

Member
Apr 9, 2012
64
Maybe it was time anyway, but I'm not sure why you replaced pads and rotors to fix the symptom you described. Sounds like a bad proportioning valve but on our trucks I believe it's built into the M/C. A stuck caliper would produce that symptom, so when you were changing pads did you make sure the slide pins were good and clean, and caliper pistons free and clean? Then check the vac line to the booster. Some cars have a check valve that looks like a 90 elbow inserted in the booster, and it makes sure the air only moves one way. Simple to check by blowing into it. Are you POSITIVE all the air is out of your lines? It's tricky sometimes when you change the M/C. You might have had the proportioning valve go bad, which was the first symptom, fixed it by replacing the part, then the condition doesn't improve, but for a different reason, like air in the lines. ARRGH. Post back as you go so future victims of this can search and learn, your title was specific to a symptom.
 

RayVoy

Member
Nov 20, 2011
939
It has been my experience, that when the pedal goes to the floor, there is a leak somewhere.

Yours may not be a large leak, if refilling the system has not resulted in an almost immediate second pedal to the floor.

Did you notice any wetness when changing the pads; how about puddles/drips on the ground; any wet areas under the truck, along the brake lines?
 

hockeyman

Member
Aug 26, 2012
726
I'm guessing that there's air in the line(s), especially if the master cylinder wasn't bench-bled and/or purged of air. Not sure if it was done though...
 

BuckeyeEvan

Member
Apr 1, 2012
63
What was the end result?
I hate my pedal. it is so mushy. First push can get it pretty far down and lack firmness. If I let off and reapply it is much firmer.
I keep my distance from the car in front of me just because I have no faith in this truck stopping on a roll's worth of dimes.
 

Chickenhawk

Member
Dec 6, 2011
775
BuckeyeEvan said:
What was the end result?
I hate my pedal. it is so mushy. First push can get it pretty far down and lack firmness. If I let off and reapply it is much firmer.
Have the brakes ever been bled? If so, and you are sure there is no air in the lines, try this. Find a gravel road, get up to 20 or 30 and slam on the brakes hard enough to get the ABS working. Do this a couple times. Your pedal will firm up nicely.

Other than that, all I can suggest is different pads. Brake pads actually contribute to the feel of the brakes a fair amount. (I like AC Delco and Akebono.)
 

Forum Statistics

Threads
23,229
Posts
637,063
Members
18,390
Latest member
jgriff

Members Online