oatesnotes

Installed new pads, rotors and drums on my 2010 LS 3 mos ago at 120k miles. All was well. About a month ago hit a pothole and all my brake pedal resistance disappeared. Had brake engagement at the very bottom of the pedal. Came to a halt and aggressively pumped brakes a dozen times and normal pedal pressure was restored. Had the same thing happen again about 2 weeks later again with a pothole hit again. Quick visual shows no fluid loss or leaks at all. No warning lites on dash. I'm thinking brake booster related but need help??

Oldblue

Did you bleed the brakes after installing those new parts?
has the master cylinder reservoir level changed just after these pot hole impacts?
the pedal going that far down, would under normal circumstances indicate air in the system, damaged brake flex hoses, and that would involve a fluid leak.
The master cylinder can be leaking , but you can’t see where, it could be leaking into the power booster.

donbrew

I would make sure all of the bolts on the calipers are tight; including the bracket to knuckle bolts. Then pull the rears and make sure the hardware is installed correctly and adjusted correctly.

oatesnotes

Didn't bleed them. In hindsight probably should have. I did check the Master cylinder reservoir level and it did not appear to have changed. Thank you for your comments and recommendations!

oatesnotes

I will double check security of all the hardware. Thanks again!

Oldblue

You’re welcome, start with a complete inspection, repair any obvious leaking connections or parts, then bleed the brakes.

geg

a strange causal relationship between getting into a pothole and losing braking properties ...
It is logical to assume that some part associated with braking is displaced from a powerful concussion. But this part recovers (or comes back) after a few pushes of the brake pedal.
I've never heard of this ...
but take a close look at the brake calipers ... is the hydraulic piston working well? Are the brake rails damaged? what kind of brake pads did you buy? is it recommended?
there is a feeling that after falling into the pit, the brake pads move and get stuck, the hydraulic cylinder crawls out further than decency allows

Lonwane

ABS is known to act screwy after a severe shock.

RJ_RS_SS_350

Good point, this is true.

skater

i have a 2011 lt have the same issue with mine rough road or bump when applying brakes pedal to floor feels like the car is shuddering pump the brakes and the pedal is back has happened numerous times now thinking booster maybe or check valve