Odd soft pedal while braking

[Ponchonutty]

OK so say that I am driving for a while and apply the brakes, the brakes are soft and the pedal feels like it will go to the floor. If I pump the brakes I have a firm pedal. There is not any pulling either direction nor are there any leaks. If I pump the brakes and hold the brakes down, there is no further travel. The pedal stays in the original location. It does not continue to go to the floor. I am due for a front brake change but other than that everything else is fine. I am at a loss as to what is going on. I don't know if I have a caliper being hung up or do I have a master cylinder going bad. Do you anyone else have similar issues? This just started a couple weeks ago and seems to be slowly getting worse

 

[Gurrzt]

it could be your rubber brake hoses are expanding and giving you the mush peddle feeling. I replaced all my rubber hoses on Sara (2001 Z28) 14 years ago, with a set of Russell SS braided hoses, pressure good to 3000 psi, the difference in the firmness of the brake pedal was like night and day.

 

[millerladam]

Yeah I second Gurrtz but it could also be the master cylinder. There also could be air in the line. The only way the piston in the caliper would be stuck and you are not pulling to one side while braking is if the piston in the caliper is stuck open but then you would hear it against the rotor while driving. If you had a piston stuck closed then it would pull to one side when you brake, which is what my brothers 1999 Suburban does because we need to rebuild the caliper or warranty it out if it's still under warranty since the last time we replaced them. I would change your brake pads, bleed the entire brake system and see if that helps. If not, then I would bet it's the master cylinder or brake lines as Gurrtz suggests.

 

[Ponchonutty]

Yeah I have brand new rotors and pads waiting. I have new calipers and master cylinder ordered as well. We will see what happens once I get to tear into it

 

[HRPdesigns]

I have a similar problem, but it is intermittent. Pumping the brakes does not seem to help, some times I get in the 07 Tahoe (baby betty) and touch the brakes and they are tight and respond with very little movement in the pedal, then the next time I drive it the pedal goes 90% to the floor before the brakes grab. Braking seems to be fine and stop me just fine, but the actual braking point on the pedal throw varies pretty much everytime I drive her.

Any suggestions?

 

[JennaBear]

Possible air in the line, also check your brake fluid level.

 

[08HoeCD]

Check for leaking piston seals.

 

[Ponchonutty]

Ended up being a bad resovior allowing moisture into the system. It had this brown scum inside it. Had to replace the master, resovior, and from calipers

 

[CrashTestDummy]

Yeah I have brand new rotors and pads waiting. I have new calipers and master cylinder ordered as well. We will see what happens once I get to tear into it

While you have the rotors off the front hub, verify the hub is in good shape. The replaceable hubs GM uses now are prone to failure, causing pad knock-back. It's a common issue with many of the GM cars, especially those used for road racing and autocross, but give the weight of a Tahoe, I'd still check them before installing the new brake parts.

The other replies are quite valid, but this is just something else to check.

 

[Ponchonutty]

Yes. I checked out the hubs too. I was planning on replacing at least one of them since they have 150k on them but they were still nice and tight