Braking Lurch '09 GT

[Dairgo]

Ok, so it's been 6 or 7 months since my car has done this, and it's started doing it again (randomly), I've had new pads and new rotors put on in the time between because it was time for it. I'm rolling along coming up to a stop, applying the brakes (I'm not slamming on them) and I'll almost be at a stop and it feels like it lurches, like it releases and clamps down to a stop.

Any ideas? My brakes haven't failed, I always stop, just that the lurch is...annoying, yes that's the word and not normal... and sometimes not normal costs money to fix.

[sideshowalan]

Sounds like you're describing a not-so-smooth downshift.
Is this an automatic? How long ago was the transmission fluid changed?

[ctgottapee]

Does sound like a lurching downshift

I'd go through a typical trouble shoot on the brakes. Make sure each caliper can move freely, pads are wearing evenly, no kinked brake hoses, etc. Possibly flush/bleed the brake lines in case of trapped air. If you get desperate, check your parking brake is set properly.

After that you'd want to possibly check that the caliper pistons are retracting properly, able to move freely, but that likely means removing the calipers. One of the pistons could be catching when you release the brakes and not releasing right away due to a bad seal, etc. If not doing it yourself this could be a lot of $ for a small issue.

[vibrologist]

My first guess is that the tranny is delaying the downshift. Maybe your idle is high, too. so make sure both the tranny and the engine are in top shape.
Check the brake booster and hose. Look for vacuum leaks anywhere in the intake manifold area.

[Dairgo]

a) it is an automatic
a2) last week I scheduled an Oil change, Brake fluid flush and Transmission fluid flush for tomorrow (thursday) before this all started as it was close to mileage marks, so we'll see what happens
b) going to ask them (good local mechanics shop) to take a look at it all and see if they see anything glaringly wrong...

[kumquat]

Does it happen with the transmission in neutral?

[Dairgo]

Haven't tried that yet, but will give it a try while I'm driving around this weekend.

[Dairgo]

well some good news, sort of...

While I was in getting the fluids done I told my mechanic about it and they took a look and did a few things (holding the brakes and stepping on the gas to see if it was a motor mount torn or loose, visually inspected the motor mounts), didn't see anything, but they drove it around and were able to reproduce the issue.

He's thinking perhaps might be with the torque converter and something described it as shock shifting. Dunno, but worth googling and looking up.