what do i need to know about hydro boost brakes?

[BrentB]

thanks again, everyone for posting. Here's an update, but hotter rear brakes and brake booster to the floor issues are still there.

Regarding rear brakes hotter than front, I have cleaned and relubed all 4 brake caliper pins, so I know the calipers slide freely. all the pads still look good. I've flushed the fluid out of all lines, and bled the brakes 3 times by the 2 man method. The rear brakes continue to get twice the temp of the front brakes after several stops, but not where I can smell them during normal braking. the brakes are not dragging, as on a long drive with a gradual slowdown there is no heat to speak of on any brakes. I called the local chevy dealer and talked to their truck shop foreman. He said in his experience the rear pads wear out before the fronts on these work trucks, but he did say that they usually are carrying some load. That indicates to me the rears do a bigger share of the braking on this truck than conventional wisdom suggests. I could never find a proportional valve, so if it has one it must be with the ABS valves.

regarding the hydroboost, I didn't ask the dealer, as I felt I had already used up my free advice allotment. Saturday, I stopped in at a used car dealer and tried the brakes on a 2006 K1500HD just like mine (mine is 2003) and the brakes went right to the floor just like mine. one rainy day I went out on a rural road and did a few panic stops, and could feel the ABS working.

I think I've gone as far as I can, and see no change since I started this project.

 

[dodge man]

It still doesn't sound right to me.

 

[the old grind]

Not sure if pedal going to the floor when stopped is a sign of trouble, tho' I'd be alarmed if it happens while driving. (If there's a pressure relief in the system it could be what's allowing it.)

Compost pile could use a top-up & stir, so now I'm inspired to fire up the 'manure fetcher' to see if my Chev does that too. ('82 1-T w/Hydro-Boost & rear drums, no ABS)

Will report. tog

 

[Gem99ultra]

It still doesn't sound right to me.

Nor to me. I've read and been told that the front brakes provide 70% of the total braking. In fact, I have 120K on my pickup - and on the second set of front pads, but the back shoes have never been changed... and they look almost like new. Somethings wrong somewhere with the info.

Perhaps I'm wrong about the booster being defective, but I'd sure not play around with a problem like this. I'd have a good brake shop look into it for sure.

 

[dodge man]

I had a sticking rear brake on my Dodge 2500 with a Cummins. It uses a hydra boost system. Once I got it sorted out I carried one of those point and shoot thermometer with me and the fronts were always hotter than the rears. I have read all this thread but not lately I assume you have replaced the master cylinder? If you have, it's rare, but I've bought brand new parts or rebuilt parts that were defective. I've also heard of the rubber hoses being a problem and needing replaced.