brake bleed nightmare

[jhelgesen]

Hey Guys,

I've been trying to get my brakes bled on the 912-6 with low sucsess. I followed the recent thread of pulling the pads to move the pistons, and using my home made pressure cap to pressure bleed the lines, plus I tapped all over the system to dislodge any air bubbles. With the pressure system pumped up, the pedal is hard, no pressure, pedal is on the floor. With the regular cap on, I can pump the pedal short a few times and the pedal gets hard, press again and its on the floor.

When I check the rotors with the pedal on the floor, the rears are stopped, the fronts have medium drag, but I can rotate them.

Sooooo, have I still got air in the system, or is the MC bad. I don't see any leaks on the floor board, and no big puddles on the floor.

Or can I find a pressure bleeder at pep boys or somewhere this weekend?

Help help help help help!

[72 four door]

John i just did mine and had a sorta the same problem I cracked the lines on the master and let it gravity bleed then i did the same on my fittings pedals nice now. Although primitive it worked well.

[jhelgesen]

Okay, I'll give it a try, thanks!

[bell]

if you had the calipers off make sure the bleed nipples are at the TOP of the caliper carrera calipers can be mixed up, not sure if yours can be.....don't ask how i know

[72 four door]

Ya know he right this just happened to me last week on my sons jeep check that out

[Zeke]

The M/C is suspect to me. I've read here that many times the M/C goes away when you bleed the brakes because you push it in further than it's been for a long time, run into rough and rusty territory with the cup seal, and blam, it's toast. I don't know for sure because the first thing I do with a car that needs any brake work is buy a new M/C.

[Early_S_Man]

How loose are the pads in the caliper? Lots of clearance = lots of pedal travel required , and there is a point at which the master cylinder doesn't have enough volume in one piston stroke to push out all four 48 mm pistons enough to apply much force on the rotor!!!

If the front pads have enough clearance that they come out easily, or if you can wiggle them ... then you need to remove them one at a time and bump the brake pedal to take up the slack ... you should have to hammer the pads back in with a plastic mallet, or you might have to pry the piston back in slightl;y ... if you pushed one out too far. The clearance should be zero putting pads back in!!!

Read this thread for a thorough discussion of the matter and the solution:

Brakes

[alow911]

Had this problem long ago. My Pads were too thin, Problem solved with new pads ! Doh

[sundaypunch]

Are you sure your homemade pressure cap is working? Sometimes homemade isn't a good solution. I would invest the $41 or so in the Motive bleeder. I would also echo Zeke's comments about the M/C if the pressure bleeder doesn't solve it.

[RoninLB]

Originally posted by Early_S_Man
. you should have to hammer the pads back in with a plastic mallet, or you might have to pry the piston back in slightl;y ... if you pushed one out too far. The clearance should be zero putting pads back in!!!

Warren's info is necessary to prevent chasing your tail.

[jhelgesen]

Okay, just got home late and ran out to the shop. Bled the mc with my helper, then went back through the calipers again. Kept hearing a gurgling sound in the right front. Pulled the line from the caliper and gravity bled it a while, then reinstalled and bled the caliper again. Pedal feels better, but I would say its at 40% where it should be. I'm headed to the hardware store early tomorrow morning to make a propper bleader system and try one more time.

John at PP said my new MC should be here tuesday if this doesn't work.

I'm getting closer and closer to taking a rental car to drivers ed.

[masraum]

Could be that the part of the Master cylinder that runs the front circuit needs to be bled.

[ubiquity0]

Do you 'bleed' the MC by just loosening each line & letting it drain, or pumping the pedal (making sure the reservoir doesn't run dry)?

[jhelgesen]

Signs are pointing more and more to the MC. Pressure bled the MC f&r, then the whole system this afternoon with no improvement. We'll see what happens this week when the new MC arrives.

[vash]

start getting yourself mentally prepared to handle those damn grommets on the top. are you going to bench bleed this time?