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Hey guys sorry if this is redundant but I’ve been scouring the forum. I recently upgraded to 06 dual pot calipers. My Z is an 05 with single pots up front and a smaller booster. After the calipers were changed, braking was weak but manageable. Last night I installed the 06 brake booster and bled the system. When I pump the pedal while the car is off it gets very stiff as it should after a few pumps. Once I start the car though, the pedal goes to the floor. I bled the system again but the result is the same.
I suspect a vacuum leak leak but I’ve traced the line and can’t find anything. Nor have I touched anything outside the vicinity of the brake box. The two metal lines that run into the master are under preasure since they’ve been moved forward about an inch. I’ve currently got them tightened down as hard as possible.
What the hell he’ll is going on here? I haven’t been home in two days. : (
(I powder coated and decaled the 06 calipers.)
Last edited by Cracka350; Aug 24, 2018 at 06:11 AM.
Reason: Updated to include caliper pics
If you can't build pressure, and you aren't leaking fluid somewhere, then there's still air in your lines. How long did you bleed after replacing the master? I don't mean to be condescending, but when you replace the master, you're introducing air into the very beginning of the system, so you have to bleed bleed bleed bleed bleed until the entire system is flushed. This should take 30 - 40 fl oz of brake fluid (~2 std size bottles).
Most likely still air in there but you might also want to check the hose coming off the booster. There is a check valve inside of the hose and if you put the hose on backwards...well you get it. It only flows one way.
I was in denial considering how long I'd been at it. I bled each caliper (starting in the rear) excessively. The master is in fine shape. But I'd hear a whisper when the car was off. There's probably a diaphragm in the booster that's blown. It's the only component that's changed since the loss of pressure. Anyway I ordered a re-manufactured one. That's what I get for buying a cheap used part.
There's some debate on the matter, but we always bleed with the car running to make sure we're getting the vacuum assist. Some cars it doesn't seem to make a difference, other cars it's made all the difference.
Try re-bleedbleedbleedbleedbleedbleeding again with the car running.
Well I ordered a rebuilt core from CarID so I could put this nightmare behind me. The booster arrives and looks right so I installed it only to find that the center inlet is too shallow for the master cylinder piston to fit. IT'S USELESS! So rage aside I'm looking for a rebuild kit so that I can replace the diaphragms and get the car on the road. (Novel concept, I know.)
Last edited by Cracka350; Aug 20, 2018 at 04:52 AM.
Update: I picked up another OEM salvage part. This time also with the shallow inlet. I did some research and found that the enthusiast boosters are different from that of the touring and up levels. So I went back and opened up the casing of the first one. It looked fine. no tares no cracks. So I reinstalled it, put teflon tape on the bleeder screws. Then used a pnuematic bleeder to bleed the living **** out of the system for a couple of hours. Its better. I actually got to drive it home. But there's probably still some air in there because the car pulls to the left and the pedal still sinks quite a bit.
Update: I picked up another OEM salvage part. This time also with the shallow inlet. I did some research and found that the enthusiast boosters are different from that of the touring and up levels. So I went back and opened up the casing of the first one. It looked fine. no tares no cracks. So I reinstalled it, put teflon tape on the bleeder screws. Then used a pnuematic bleeder to bleed the living **** out of the system for a couple of hours. Its better. I actually got to drive it home. But there's probably still some air in there because the car pulls to the left and the pedal still sinks quite a bit.
once you get air in the ABS unit, takes forever to get it out.
Well the more progress I make, the dumber I feel. I took Terrasmak's advice and did another bleed session with the car running. Brake feel has significantly improved since the last session. I'm pretty sure the left front caliper needs another go. Considering I did alot of forum and google searching on equipment specs, there seems to be very little about the variations between enthusiast level systems and otherwise as well as 2003-2005 vs 2006-2008 components. So far the front calipers and the booster have changed. But the new calipers have increased clearance to accommodate larger discs. So new disks are in my future. Anyway the picture here shows the extra centimeter unused brake pad against the old disk.
Cracka350's Brake system update
