Soft Brake Pedal

[JACKFAVOR]

I have a 2001 yukon thats brake ped is very soft. The pedal can be pushed to the floor but no warning lights come on. The truck stop Ok but takes alot of pedal. The pads are good all the way around I had the fluid flushed and replaced and still have the problem. The fluid level is also good. Any ideas?

[KRT]

Master cyl

[Ranger]

Try bleeding the brakes first, and if it continues replace the master cylinder.

[MarkD]

Who did the flush?

[pennzoil29]

Try bleeding the brakes first, and if it continues replace the master cylinder.

 

+1

[JACKFAVOR]

Firestone did the flush.

[Draenor]

First bleed the brakes. If that does not solve the problem follow the procedure below._This is for non-hydro boost applications)

 

With the engine off, pump the brake pedal to remove any residual vacuum in the booster.

Hold pressure on the pedal while you start the engine. When the engine starts, the pedal should drop about a 1/4", this indicates that the booster is working properly.

 

Next

 

Run the engine a couple of minutes.

Turn the engine off and press the pedal several times slowly. The first pump should be fairly low. The second and third should become slightly firmer. This indicates an airtight booster

 

Next

 

Start the engine and press the brake pedal, then stop the engine with the pedal still pressed. If the pedal does not drop after holding the pressure on the pedal for 30 seconds, the booster is airtight.

 

If these fail inspect the check valve.

 

Disconnect the vacuum hose where it connects to the intake manifold. Do not disconnect the vacuum line from the booster. Air should not flow when pressure is applied, but should flow when suction is applied. If air flows in both directions or there is no air flow, the valve needs to be replaced.

 

Last

If the other test pass, next is to check for vacuum. Run the engine and see if there is vacuum comming from the engine at the hose before the cylinder.