NTH

So my GX has 103k mi and has been flawless. Did a search but came up with nothing. For about a month now, I've been feeling a weird sensation through the brake pedal. I've only felt this with the car at rest and my foot on the brake pedal. While holding pressure, I would feel like a pop sensation, kinda like a spring popping off something sensation. The pedal never drops further or lose braking pressure. Again I've never felt this while driving, just at rest like at a stop light. Anyone have any idea or ever heard of this? Thanks

chiph9

Turn your A/C off and see if it happens again. The compressor puts a large power draw on the engine, and the computer will change the RPMs to counter it. If you're sitting on the brake, you can sometimes feel the difference.

If that's not it, take it by the dealer. The vacuum booster sometimes (rarely) goes bad.

Chip H.

NTH

Tried ac off, but still felt the pop on the brake pedal when holding pressure. Anyone else experience something similar?

new2012jee

Yes, all the time, I kinda just blew it off it was so normal. First time it happened I thought I got rear ended or someone bumped me. Its normally if I don't depress the pedal fully, like I have a 50% press down, but car is still stopped, I will notice like 2 or 3 hard pops through the pedal.

new2012jee

Just an FYI, I had my rear pads and rotors replaced, and this issue is gone.

Lextech43

Sounds like it might be the driveshaft. The usual complaint for that is a clunk or bump after coming to a stop. I feel it in mine at times. It also happens when I'm stopped down hill and the suspension settles. There is an updated driveshaft available to remedy this.

NTH

Lextech- no, not the driveshaft. I've driven a GX with that issue and know exactly what that was like. I have a replacement done already. Hard to describe but the pop is at the brake pedal. It feels like a spring letting go, with a "dwoing" sensation.

new2012jee

Yep, feels like the pressure pushing back up against your foot on the pedal, but in rapid succession, typically around 3 times or so. My mechanic said that when the pads wear down enough, the pistons are at a fixed limit, but can still go further down to the pad, and it is the attempt of the brake system to push harder, you feel the pop from the pressure. Not sure how viable that is, but when he replaced the rear rotors and pads, this issue is completely gone. Hasn't happened in over 2 weeks now.

NTH

^Exactly! You may be on to something here. My brakes will need replacement soon, probably before winter. I'm planning for complete rotors and pads, including a flush. Thank you for your feedback!