Hey Guys,
So i recently decided to finally do the brakes on my LSJ as they had became quite annoying.

I replaced the Pads & Rotors on all 4 corners.

Both rear calipers had issues so i swapped them for new ones.


After replacing rear calipers we began to bled. I followed the order: RR, LF, LR, RF.
I have bled each wheel probably 10 times now. I have not seen an air bubble in the past about 4 bleeding's. All 4 bleed valves are facing correctly upwards.

After the bleedings the pedal is firm with the key in the "on" position but not fired up. As soon as i start the car the brake pedal is completely squishy. This has been the story after each of the bleedings. Im following every process i know and have done brakes on 20+ cars previously without ever having this issue! (except 1 time having calipers upside down)

The fluid each time comes out steady, clean stream while as soon as the car is fired up the brake pedal loses all stability. I have heard that it is possible to get air in your ABS Module which would lead to a similar problem? I read you will need Tech2 which i dont have. But have friends with an automotive shop and "LAUNCH" control which im hoping can tap into GM.

The only other thing i can think of, is the possibility that 1 or both of the new calipers had the piston adjusted too far out? Thus once the car is started there a gap of fluid created from the longer stroke

 

I know back in the days on the F-Bodys you could lift the car, put it in gear and "stop" one the free spinning wheels. It would freak out the ABS and "hopefully" get most of the air out of the system. Might work on the Balt. I'm guessing when you bled the brakes you let the master cylinder get too low?

Let them gravity bleed for 40 minutes; always checking to make sure your topped up on brake fluid.

 

Did you bleed ALL four wheels? Sometimes a piston that's been extended (front caliper, low pads) for awhile, becomes rusty and when your press it back in to install new pads will cut the piston seal allowing air to seep back in. I'd check that.

 

Could try pressure bleeding it.

 

That isn't a bad idea, i was wondering what way i could trick the ABS module into opening up without having the software.

Yes i did, all 4 several times. Each following the specified pattern and i placed 2 new calipers on the rear of the car. (it appears last time only the rear brakes were gone as after taking apart the front brakes still at about 70% while rears were gone)

Going to probably give it a shot, but after the length of manual bleeding i did. Im not sure that will do too much good

 

where did you get the rear calipers from? were they rebuilt calipers?

 

Rear left i ordered with my brakes and is a NEW AC Delco.
Rear right i found was seized after the fact. So bought a Master Pro from O'riellys which i would imagine is a reman

 

I have the same issue. I use bleed valves with a check ball in them and a clear hose to check for air coming out.

I have not had this issue bleeding brakes on GM W Body cars.

I bought a pressure bleeder, but haven't tried it yet.

Probably not related, but the car pulls to the right under hard braking (just short of the ABS coming on).

 

Well good to know im not alone!

I honestly never had the pulling issue so im not sure, but definitely let me know how it goes with the pressure setup!

 

Pressure bleeding is amazing, I had to rebuild most of the brake system on a hyundai sante-fe that had a failed ABS module causing two calipers to drag, and bleeding all of it manually would have taken forever, especially since the module was above the master cyl level. Power bleeding took 5 minutes to push solid clean fluid through to all 4 corners by myself, no helper needed. Can't beat that.

 

Honestly the failed ABS module could be my issue. I did the brakes all around as i had ordered the parts but when i took them apart... The fronts have 85% left on the pads and the back had lipped into both sides of the rear caliper. Did the failed ABS module throw a code?
Ill have to run the scanner when im home. I wouldn't have noticed as with my CAT delete i consistently have the check engine light on

 

I think red sox had an issue with his abs like this. Would be cool if he chimed in.

 

On the hyundai, yes it had some ABS codes but it was also intermittently locking up two of the wheels, so I knew it had to be a fault in the ABS pump/module

 

Ah gotcha well i never felt any wheels lock up. So ill get the code scanner on it tonight and see if the ABS is kickin anything back

 

Sox had an lnf not an lsj, different brake system.

Did you pump the pedal bleed them or vacuum on the bleed valve? When you pump the pedal you can go to far and damage a seal in your master.

 

when did the poor pedal feel start? was the pedal solid before you changed the calipers and bled it, or did it happen after? if the pedal feel wasnt great before hand you could have a bad brake hose. what can happen is the hose expands with pressure and as a result the pedal travel is used up expanding the hose instead of pushing the caliper piston.

aside from that, im going to guess you have air in the abs unit. you can try jacking the car up, getting the tires rolling and braking to active the abs. the key here is get the front tires going about 10-20mph then slowly stepping on the pedal, dont hammer the brakes. after doing that a couple times you will have to bleed the brakes again. using a scan tool that can activate the abs bleed is the best way though.

 

To go along with the pressure bleeding, my friend couldn't get the clutch to bleed on his Redline and they tried pressure bleeding and it worked like a charm. Same system on this car.

 

*****SOLVED!!!!******
After purchasing a pressure bleeder and bleeding the system once i could tell something was still off.
After checking each caliper i found that the rear right was too far out and binding up the wheel even with brakes off.

I took the caliper off adjusted the piston a couple times. Pressure bled the system 2 more times and VIOLA!
Brakes feel great and car stops on a dime!

Moral of the story. BUY A PRESSURE BLEEDER!

I believe that after leaving the caliper off overnight there was either air in the ABS or so much air in the system that the manual bleeding was not able to handle it. Took 3 times total around the car with the pressurized system and now good to go!

Thank you brothers for all the help!

 

Nice. I've also read on here that calipers need to be diagonally bled if you don't pressure bleed due to design. Don't know how true that is though.

 

Yeah it's been awhile. Couldn't remember.

 

Hm interesting, hadn't stumbled upon that before.

Anyways i am 100% amazed with the pressure bleeding system. $30 at harbor freight is worth its weight in gold

 

Same way I felt after using it. i'll have to look into the harbor freight kit, all I used was my generic pressure tester for cooling systems, used the universal end that would seal up on the master and pumped it up

 

I had this same issue

Came out to be I had the left caliper on the right side and right side on left lol
All bolted up the same.

 

Great to hear. What PSI did you bleed it at? I'll be doing this in the future when I install steel lines. I want to say 10 psi is enough.

 

Had that happen on a truck previously. Always remember, nipples up!

Not sure what the pressure was at the trigger as the setup from harbor freight doesn't have a gauge. The instructions recommended running your compressor regulator between 100-120 PSI