Soft Brake Pedal

M1Tanker · July 22, 2009

2007 Silverado Classic Z71 EXT Cab 4x4...had my rotors replaced by a local guy and they were still vibrating. Took the truck to the dealer and they turned the rotors...smooth as silk but now the pedal feels softer and I have to use more force with my foot to stop. I have driven it over the weekend to see if the brakes would set themselves and the pedal would get firmer...nada.

They left the original pads on and I was told they were still 60% +.

Any thoughts on the soft pedal. The dealer told me they could "rough" up the rotors but I am skeptical that it would help.

The truck has 57,000 miles on it and obviously I got semi-hosed by the local guy. He and I have had a chat with no results.

SSnakeAce · July 22, 2009

2007 Silverado Classic Z71 EXT Cab 4x4...had my rotors replaced by a local guy and they were still vibrating. Took the truck to the dealer and they turned the rotors...smooth as silk but now the pedal feels softer and I have to use more force with my foot to stop. I have driven it over the weekend to see if the brakes would set themselves and the pedal would get firmer...nada.

They left the original pads on and I was told they were still 60% +.

Any thoughts on the soft pedal. The dealer told me they could "rough" up the rotors but I am skeptical that it would help.

The truck has 57,000 miles on it and obviously I got semi-hosed by the local guy. He and I have had a chat with no results.

Sounds like you need to bleed the brake system.

Spurshot · July 22, 2009

+1 on the need for bleeding.

redsled2007 · July 22, 2009

Just to throw something into the mix, and since you just had new rotors installed and then turned, reminded me of an issue I had with an 89 T-bird of my wife’s.

Same original problem. The dealer replaced the rotors and turned them. I took the car out to test the brakes and when I tried to make a hard stop from 40 mph, I had to push as hard as I could to stop.

The dealer checked out the system and said that everything checked out to “Spec”.

To make a long story short seems that the original “specs” were absolute minimum thickness for the rotors and after the dealer turned them, they went below minimum. A TSB and recall came out about a week later to replace the rotors.

Point is, check to see if the rotors are below spec. (Thickness) when your mechanic turned them he might have gone to far.

rjirvine · July 22, 2009

If the pedal is soft, you need to bleed the brakes. Remember, RR, LR, RF, LF is the sequence. Since it's 2007, I doubt you need new bleeder screws. If your truck was older I would have recommended having some on hand. I like the Valvoline synthetic brake fluid. Use a boxed end wrench too so you don't flatten the nuts. A shot of PB blaster will help them loosen if they need it. My wife and kids would always roll their eyes when they had to help me bleeding my brakes...ie NO! I said release, not depress! I finally went with a pressure bleeder I got off of ebay for about $70..that thing rocks!

BTW, Why didn't you replace the pads when you changed the rotors and be done with it? Also, google "seating brake pads". I didn't know such a thing was needed, but it seemed to help with mine.

LousCrew · October 14, 2009

OK, same problem as OP here on my 06 GMC CCSB. I brought the truck into the local dealer and they replaced the pads (were in the "yellow"), turned the rotors, and replaced the brake booster. I picked the truck up today and the pedal feels a little better, but not much. The dealer mentioned that I may need to replace the master cylinder as well...something about driving with a soft pedal put excessive wear on the piston; thus, wearing out the master cylinder.

What do you guys think?

LousCrew · October 14, 2009

Well, I did some basic diagnostic testing after reading a pretty good article online and feel pretty certain I have an internal leak in the master cylinder. Looks like I'm back at the dealership in the morning

For those who are curious, basically I pumped the brake pedal (while car was off) several times. Had my wife verify there were no visible leaks. Low and behold, there were no external leaks; however, the pedal slowly creeped down to the floor all the while the fluid levels still looked good. I am disappointed that a mechanic at a GM dealership could not (or did not) perform the same test.

Oh well, lesson learned, don't always trust the dealership service department with your tome and money!

LousCrew · November 17, 2009

Update: well, it's been a month. I had the rotors turned, pads replaced, new brake booster installed, and new master cylinder installed. Total damage: $950. The brakes and pedal feel are 100% better. However, in the last day, the brake light on the dash started radomly coming on. It hasn't done it consistently enough for me to determine conditions/scenarios.

Any ideas? It isn't the ABS light, just the brake light. It doesn't flash, merely comes on just long enough for me to see it.

georgecdisc · November 17, 2009

Have you checked to make sure there is plenty of brake fluid still? Maybe the sensor is going wacky?

Mossyoakglock · November 17, 2009

Will stainless steel brake lines firm up the pedal feel too? What brand woud you recommend?

Also, do you think it would be possible to make your own Pressurized power bleeder? I have an old garden pump sprayer that lookes exactly like the Motive power bleeder. I was thinking about putting a pressure gauge on it and finding an attachment for the cap. Do you think that might work?

Sorry for the thread jack.