Hey all,
2012 Impala LS 3.6L w/ 130k miles here, just finished up a rear-right caliper replacement. I'm having some troubles diagnosing a brake issue. Here's what I've done so far after the caliper replacement. Note that these issues were not present prior to the caliper replacement (it was replaced because it was seized).
Bled the brake lines ordering RR > RL > FR > FL. No visible leaks from any line. The brake pedal was spongy when the car was off and went to the floor with basically no brakes after we turned the car on.
Bled the ABS unit with an automatic scan tool ordering FL > FR > RR > RL per the instructions on the tool.
Re-bled the brakes in using the first order above. The pedal is still spongy and floors when the engine is turned on.
There doesn't seem to be any hiss when depressing or releasing the brake pedal with the engine on. The same can be said when the engine is off and all the bleeder valves are closed. If we bleed some fluid from one valve and close it again, there is a hiss from the booster upon releasing the brake pedal. Is this indicative of an air leak somewhere in the master cylinder or booster?
There appears to be some slight resistance if I quickly depress the brake pedal with the engine on, but that fades very quickly.
I'm unsure what to do at this point. I'm less familiar with master cylinder or booster issues, if this is the case.
Any suggestions on next steps? I'm tempted to call a shop, but want to resolve this in-house if possible.
2012 Impala LS 3.6L w/ 130k miles here, just finished up a rear-right caliper replacement. I'm having some troubles diagnosing a brake issue. Here's what I've done so far after the caliper replacement. Note that these issues were not present prior to the caliper replacement (it was replaced because it was seized).
Bled the brake lines ordering RR > RL > FR > FL. No visible leaks from any line. The brake pedal was spongy when the car was off and went to the floor with basically no brakes after we turned the car on.
Bled the ABS unit with an automatic scan tool ordering FL > FR > RR > RL per the instructions on the tool.
Re-bled the brakes in using the first order above. The pedal is still spongy and floors when the engine is turned on.
There doesn't seem to be any hiss when depressing or releasing the brake pedal with the engine on. The same can be said when the engine is off and all the bleeder valves are closed. If we bleed some fluid from one valve and close it again, there is a hiss from the booster upon releasing the brake pedal. Is this indicative of an air leak somewhere in the master cylinder or booster?
There appears to be some slight resistance if I quickly depress the brake pedal with the engine on, but that fades very quickly.
I'm unsure what to do at this point. I'm less familiar with master cylinder or booster issues, if this is the case.
Any suggestions on next steps? I'm tempted to call a shop, but want to resolve this in-house if possible.