jwd

Sigh.


Tried changing pads and rotors last week.

Ordered Z51 rotors from Ecklers, and Z51 pads from GM Parts House...

Had the dealer do a full flush/bleed w/ Tech2. I'd planned to do this anyway. It'd been over a year since the last flush. Peddle got softer and more travel, had to go back and have them redo the flush/bleed. Seems better now...

Have gone through the bedding process.. Rear rotors still don't look like they're bedding properly.. It's like the rear pads aren't making full contact...

Even after two bedding attempts, car just doesn't stop properly. I can burry my foot into the floorboard w/o the ABS even thinking about engaging.

(No not trying to panic stop engage the ABS right after any attempts at bedding, this is hard braking the next day)

Honestly not sure what to even try next.


Extremely frustrated.


Any thoughts/suggestions? Anything I should look for that could be causing braking issues w/ new pads and rotors?

AORoads

I don't have answers for you, but maybe I can ask some questions for next person. Did you have the dealer do the bleed/new fluid first, or after the brake pad/rotor installation? What kind of miles and type of driving on your '08?

I can't be certain but if ABS isn't activating, seems like there isn't enough line pressure which sometimes means air in system or brake master cylinder (or proportioning valve but that may be electronic/computer controlled). I have heard of the last-mentioned needing to be replaced which is strange (to me) since it's usually a long-lasting item.

You replaced the pads and rotors because they looked worn or weren't giving good stopping power? It may be the last time it was bled, it wasn't done sufficiently either. Someone else will chime in I'm sure.

Good luck with it. Do a search on brakes, bleeding, master cyl., etc. in advanced search for C6 Gen and Tech. May uncover your reason/issue and solution.

0Anthony @ LGMotorsports

The Tech II bleed can un-cover some issues in the ABS box or possibly a valve is stuck...

However.

I am still a big believer in manual two person bleeding because you can see what is going on with it, and see if there is any air coming through the lines, or maybe there is a leak at a line, or a crush washer that you wouldn't see using a machine or one person bleed system.

Since you still have the stock calipers a few things I would look at.

• Are the calipers free to move on the sliders?
• do you see any leaking at the pistons?
• Did you wash the rotors of any grease or oil when they went on for the first time?

I know you said you bedded them in, but you might try taking the pads out and sanding them lightly as well as the rotors and then washing them down.

Being that you are not getting into ABS tells me a couple things or a possibility of a few things.

• Check the PN on the pads. If it isn't a Z51 pad, and might be a ceramic pad that could be one issue
• if the pedal is soft you might have air in the system from a leaking line, fitting, or caliper seal. Could also be a hurt soft line too
• Do you see any error codes for Traction control, Active Handling, or ABS?

jwd

I took some time to re-bed the brakes...

Final bed-in procedure...

1. 10 35mph decelerations
2. 5 45mph decelerations
3. a few 60-30 decelerations


Rear brakes *finally* looked like they were taking material/bedding-in...

Next day tried some hard braking and was able to get the ABS to activate..

Recent AutoX went well.

Peddle still seems a touch longer than before.. Wondering if the Tech2 has uncovered some additional issue yet to become clear?

jwd

Thanks

jwd

Thanks

Cherokee Nation

Dump Question: This is the first car that I have owned that has ABS,how do I know if the abs is working??...

mikeCsix

That's easy, stand on the brakes - hard. You'll feel the abs kick in by a pulsation in the pedal and you'll feel/hear the chatter coming from the brakes and tires. Also, the tires won't lock up on you as evidenced by your ability to steer the car with the brakes on hard.

Cherokee Nation

Thanks..That is what I was thinking..My classic car,when I hit the brakes the tires lock up....

Bill Dearborn

It is a violent reaction when you jam the brake pedal on hard. The pedal will vibrate (designed to do that so you know ABS is working) and if you are going fast enough and jam the brakes on the ABS will alternate the line pressures at each wheel as necessary to bring tire slip to the correct point for max deceleration. Each tire will be grabbing and releasing based on the surface traction each sees. The whole car will vibrate quite a bit when doing this on a clean and dry road. To get 4 wheel ABS you need to be going fast enough the front tires can't provide all of the stopping power and have to hit the pedal hard. I usually give it a try when running about 60. Make sure nobody is behind you when you slam the pedal. If the tires lock up and smoke let off the pedal.

Bill

Tonylmiller

I'm not as familiar with these fancy new braking systems, but if I had a mushy pedal and I was confident that all air had been removed (and no fluid leaks), I would be checking the master cylinder. You could always go with steel brake lines, but the pedal should not be soft with the stock brake lines, either.