Coming back from Jim`s for breakfast this morning my trucks brake pedal would start shuddering when applied. Even when sitting still in driveway it does the same thing. Redid the brakes not too long ago.I just checked and it`s not throwing any codes,fluid is fine.Need to go to Tahoe tonite so pls. chime in with any ideas
Thanks
Hanklin
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By shuddering do you mean the pedal bounces slightly when pressure is applied?

Could be a hydro boost issue, hows the PS pump?
Brake Booster

With the transmission in NEUTRAL and the engine stopped, apply the brakes several times to exhaust the vacuum in the vacuum boost system or the pressure in the Hydro-Boost system.
Hold the brake pedal in the applied position.
Start the engine.
If the power brake system is functioning properly, the brake pedal can be felt to move downward after the engine starts.
With a vacuum type power brake booster, if engine vacuum is available to the power brake booster and no power assist is felt, replace the power brake booster and retest the system.
If power steering pump pressure is available to the Hydro-Boost power brake booster and no power assist is felt, replace the Hydro-Boost power brake booster and retest the system.

If power steering pump pressure is not available at the Hydro-Boost power brake booster, check the power steering pump pressure and flow.

Accumulator, Hydro-Boost Only

Start and run the engine.
Stop the engine.
Apply the brakes. The accumulator in the Hydro-Boost power brake booster should retain enough pressure for at least two power assisted brake operations. If no power assist is felt, replace the Hydro-Boost power brake booster and retest the system.

 

The "shuddering" even when you are stopped in the driveway... almost sounds like something is mal-functioning with the anti-lock system. Have you ever felt what the pedal does when the anti-lock kicks in?? Is it that same kind of shudder??

 

By shuddering do you mean the pedal bounces slightly when pressure is applied

Exactly,Ialso a like a bump,bump bump noise,I`ll go try what you said and post again shortly
Hanklin

 

Oh , Ialso checked the abs fuses and found them to be good
Hanklin

 

Alan
That didn`t work,I also don`t have any power steering assist,so am I looking at the powersteering pump as the culprit?
Hanklin

 

Sounds like that is it. Those "Bounces" you felt in the pedal were probably the last of the presure from the PS pump as it died.

Double check and make sure the PS pump didnt just puke all the fluid out before you replace it.

 

Thanks for the help,better get started,dosn`t look to fun,oh well
again many thanks

Hanklin

 

Ahh the anti-lock is more like a real strong vibration in the pedal - and you can HEAR it too....

Good luck changing out that pump - let us know how it goes - I have a feeling I might be doing mine before long.....

 

Chad
I decided to wait till mon. morning to start but I gotta figure 209,000 is a bit overdue. I`m real happy I wasn`t up in Tahoe already and have it go out, somehow changing it in the snow in a parking lot,,brrr
Hanklin