2001 Silverado Brake Pedal

Paul94Z28 · #1 10-15-2007, 08:42 AM

Hi Board-

Interesting issue with a 01 Silverado. Brakes are fine, except when cornering hard and pedal goes to the floor. Seriously, no other issues.

I am thinking master cylinder.

Any thoughts?

MT-2500 · #2 10-15-2007, 08:50 AM

Quote:

Originally Posted by Paul94Z28

Hi Board-

Interesting issue with a 01 Silverado. Brakes are fine, except when cornering hard and pedal goes to the floor. Seriously, no other issues.

I am thinking master cylinder.

Any thoughts?

Odd operation.
Any abs brake lights?
I would get a scanner on it and check abs brake operation.
MT

HanibalTheCannibal · #3 10-15-2007, 09:54 AM

Hard cornering+braking= drifting?

Weird issue. I have the same truck and I havent experienced that. A loss of vacuum could cause the mooshy pedal

silverado122775 · #4 10-15-2007, 10:37 AM

That is strange, but maybe the preasure of the turn and braking is cause a line to open up somewhere. Have you checked the level of your brake fluid?

j cAT · #5 10-23-2007, 06:07 PM

check for proper level in brake res. if ok, bleed brakes, could be air in brake system.

Paul94Z28 · #6 01-25-2008, 09:22 PM

Thanks - will try it.

SLJ2137694 · #7 01-26-2008, 10:16 AM

Quote:

Originally Posted by Paul94Z28

Hi Board-

Interesting issue with a 01 Silverado. Brakes are fine, except when cornering hard and pedal goes to the floor. Seriously, no other issues.

I am thinking master cylinder.

Any thoughts?

Could you be getting an activation of the ABS system? Deactivate the ABS by pulling a fuse and see if the pedal drops in the same circumstances. Do this carefully where you won't hit anything, you will still have normal brakes. It is common to feel something in the brake pedal on many ABS systems when they are working. A loss of vacuum will give you a hard pedal.

Paul94Z28 · #8 10-20-2008, 08:38 PM

Replaced the wheel bearing and the issue has gone away.

I do not completely understand why.

SLJ2137694 · #9 10-20-2008, 10:16 PM

Quote:

Originally Posted by Paul94Z28

Replaced the wheel bearing and the issue has gone away.

I do not completely understand why.

The new wheel bearing probably came with a new ABS sensor in it. I would say you were getting a false activation of the ABS system due to a wheel speed sensor issue or bad reluctor ring in the wheel bearing. This is why I previously asked you to deactivate the ABS and see if you still had the problem. If the problem went away and your base brakes were fine that points to an ABS problem. Now do you understand?

j cAT · #10 10-21-2008, 10:00 AM

Quote:

Originally Posted by SLJ2137694

The new wheel bearing probably came with a new ABS sensor in it. I would say you were getting a false activation of the ABS system due to a wheel speed sensor issue or bad reluctor ring in the wheel bearing. This is why I previously asked you to deactivate the ABS and see if you still had the problem. If the problem went away and your base brakes were fine that points to an ABS problem. Now do you understand?

If this wheel bearing replacement solved this brake pedal to floor issue , I would say that the ABS is defective...If it were an ABS sensor issue the pedal would not go to floor but pulse ..if abs was ok....

since the bearing was replaced , this then corrected the sensor output voltage, which then stopped the ABS from activating, in a mode which is improper..

as everyone knows these vehicles have a very poorly designed sensor mounting issue... the rust forces the sensor out of range. this then causes the sensor output to fall below 300MV AC...this is when the ABS will activate and start pulsing..

the reason I am geting into this is because if one is out of range I'm sure the other sensor is ready to soon act up..the way to check is to locate the output conector at sensor and with a meter measure for 500MV DC with the wheel rotating...

also the abs should be tested for proper operation...

SLJ2137694 · #11 10-21-2008, 10:45 AM

In my 20+ years handling brakes for General Motors Corporation, I have learned from talking to hundreds of consumers and technicians that many times, when the ABS activates at an unexpected time or when it is getting a false signal and it gives a false ABS cycle, the driver states the brake pedal went to the floor. In these cases of a false cycle, fixing the cause of the false cycle will take care of the complaint and there is nothing wrong with the system that would give a real "pedal to the floor" complaint. In these cases worrying about the rest of the system is a waste of time and money. If a component fixed a false activation and there were no other legitimate complaints with the system, I would leave it alone. As for testing the ABS, the system goes through a self test on each key cycle. If a sensor tests within parameters but occasionally drops a signal or reports a wrong speed, the system thinks it is operating correctly and does not set a code, but the complaint could be "pedal to the floor" or a comment on the ABS working when it normally would not activate.

Wayne60 · #12 10-21-2008, 02:34 PM

Are there any real cons to permanently disconnecting the ABS system ?

I'm going from a 92 to an 01 and don't like the feel of the pedal.

Thanks.

MT-2500 · #13 10-21-2008, 03:17 PM

Quote:

Originally Posted by Wayne60

Are there any real cons to permanently disconnecting the ABS system ?

I'm going from a 92 to an 01 and don't like the feel of the pedal.

Thanks.

It is a safety big safety issue.
And illegal to do it.
It could turn you in to a con.
If it resulted in a bad accident and the right lawyer and judge got on to the fact you did it.

j cAT · #14 10-21-2008, 04:13 PM

Quote:

Originally Posted by SLJ2137694

In my 20+ years handling brakes for General Motors Corporation, I have learned from talking to hundreds of consumers and technicians that many times, when the ABS activates at an unexpected time or when it is getting a false signal and it gives a false ABS cycle, the driver states the brake pedal went to the floor. In these cases of a false cycle, fixing the cause of the false cycle will take care of the complaint and there is nothing wrong with the system that would give a real "pedal to the floor" complaint. In these cases worrying about the rest of the system is a waste of time and money. If a component fixed a false activation and there were no other legitimate complaints with the system, I would leave it alone. As for testing the ABS, the system goes through a self test on each key cycle. If a sensor tests within parameters but occasionally drops a signal or reports a wrong speed, the system thinks it is operating correctly and does not set a code, but the complaint could be "pedal to the floor" or a comment on the ABS working when it normally would not activate.

this reported problem was pedal to floor...replaced front wheel bearing and the problem is solved.....

If the sensor output was dropping out for more that 15millisec... then the abs should activate... this would mean pulsating brake pedal....not pedal to floor...

If the ABS has an excessive dump/isolation time this would cause the symptom of pedal to floor...

If this were my vehicle I would make sure that when the wheels lock up that the ABS is pulsating....if not there is a problem.. need DTC...

j cAT · #15 10-21-2008, 04:31 PM

Quote:

Originally Posted by Wayne60

Are there any real cons to permanently disconnecting the ABS system ?

I'm going from a 92 to an 01 and don't like the feel of the pedal.

Thanks.

If you don't like the pedal feel, this would not be an ABS issue...this is usually a simple brake fluid replacement...the new brake fluid will give better /higher pressures to the pads...

It could be other componets also , but this is the most common answer..

in 1992 GM used a better higher quality caliper ...the 2001 is suseptible to corrosive road chemicals.

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