Braking trouble

[Dariusz Salomon]

Hi all-99 Tahoe Z71 5.7-for some time I noticed something worrying which I think is getting worse so time to address it.
When I start the truck I drive about 300 yards to the junction with a main(ish) road which happens to be downhill. When I slow down for the t- junction and coming nearly to a stop,the brake pedal at this last phase of stopping sometimes(quite often) becomes instantly harder than it normally is and I experience "getaway"sensation(lose of braking)-naturally I press the pedal more and it stops. Then I can drive it no problem-it doesn't happen again-until yeaterday when it happend again by my house-but this time I've heard a "brrrr"sound-like a compressor when it kicks in.
Anybody had anything similar? I think it may have something to do with the brake booster judging by symptoms. Am I thinking in a right direction? Appreciate your input.

 

[Schurkey]

Perhaps a moderator will move this to "Axles and Brakes" instead of Suspension.

WHAT VEHICLE??? WHAT YEAR, WHAT MODEL?

When I slow down for the t- junction and coming nearly to a stop,the brake pedal at this last phase of stopping sometimes(quite often) becomes instantly harder than it normally is and I experience "getaway"sensation-naturally I press the pedal more and it stops as normal.

I have no idea what "getaway sensation" is.

I've heard a "brrrr"sound-like a compressor when it kicks in.

Anti-lock activating?

Anybody had anything similar? I think it may have something to do with the brake booster judging by symptoms. Am I thinking in a right direction? Appreciate your input.

Jack up vehicle, remove wheels for inspection of front and rear brakes. Verify fluid level in master cylinder. Assure booster has adequate vacuum supply, and holds vacuum.

 

[GoToGuy]

The compressor sound was the antiskid module activation. As designed, you applied more brake pressure, conditions were met approaching a wheel lock/ skid and brake pressure was modulated to prevent a skid. If the brake pedal doesn't feel normal/ right. Brakes doing unusual actions. Get it fixed! Can't stop, blow through a Redlight, Stopsigns = screaming, swearing, crunching noise, .

 

[Dariusz Salomon]

Perhaps a moderator will move this to "Axles and Brakes" instead of Suspension.

WHAT VEHICLE??? WHAT YEAR, WHAT MODEL?

I have no idea what "getaway sensation" is.


Anti-lock activating?


Jack up vehicle, remove wheels for inspection of front and rear brakes. Verify fluid level in master cylinder. Assure booster has adequate vacuum supply, and holds vacuum.

Brakes are all new at the back-brake lines included. Brakes evenly-not pulling to one side.Fluid level is correct.Pedal is not going into the floor as per description. And I'm aware of what basic checks I should perform-that's not why I posted my question-it's aimed more for those who might have had similar experiance but thanks for trying.

 

[Dariusz Salomon]

The compressor sound was the antiskid module activation. As designed, you applied more brake pressure, conditions were met approaching a wheel lock/ skid and brake pressure was modulated to prevent a skid. If the brake pedal doesn't feel normal/ right. Brakes doing unusual actions. Get it fixed! Can't stop, blow through a Redlight, Stopsigns = screaming, swearing, crunching noise, .

Thanks for it-tho speed that I was doing when antiskid kicked in was really low-but since I never heard it activating before that may explain it. And I will have it fixed but I'm looking for reasons of that behavior-like I said somebody might have had it before and will poin me in right direction.

 

[GoToGuy]

You could just say what exactly happens and if any maintenance was done before or after the problem you are experiencing.

 

[mattillac]

Back when my 1999 k2500 was newer and still had the factory (smaller) sized tires, during normal braking, if the front wheels did any hopping while stopping (even on dry pavement), the ABS would kick in. Never really felt like it was helping me though, always got that (runaway) feeling that I was no longer in control of the brakes. The hard (maybe even rising) pedal and ABS buzzing (like a compressor) loudly under the hood was not a real confidence builder either.

With a bit bigger tire, my pothole/bump in the road while braking (ABS) "problem" seems to have gone away.

 

[Frank Enstein]

That is the exact reason I removed the abs from my 94 suburban.

 

[Dropped88]

Ive dealt with that same issue and mine was from the reluctor wheel and abs sensor with build up crud on back side of rotor would only do it at slow speed stopping.

On the scan tool you could watch the wheel speed sensor signal flat line and abs would activate.

 

[AuroraGirl]

Perhaps a moderator will move this to "Axles and Brakes" instead of Suspension.

WHAT VEHICLE??? WHAT YEAR, WHAT MODEL?

I have no idea what "getaway sensation" is.


Anti-lock activating?


Jack up vehicle, remove wheels for inspection of front and rear brakes. Verify fluid level in master cylinder. Assure booster has adequate vacuum supply, and holds vacuum.

getaway sounds like while braking the assist is either lost or the rear brakes arent adjusted right, and then the truck starts trying to push the truck while it downshifts to 1st and the idle speed is decent. Would be hell of a noticeable event in the snow and ice probably start fishtailing while barely moving