brake frustration

[arter]

Here's my tale of woe...rblt master cylinder(bench bled), new rear wheel cylinders, rblt front calipers, new braided lines, bled til every tiny bubble out. Type 'w' proportioning valve, held pin in with clamp to bleed rear, let out to bleed front. Have good pedal when engine off. Start motor and pedal goes to floor. Did the booster checks in Haynes manual, depress pedal and start engine, pedal gives; turn off motor and pedal builds up after one pump; disconnected booster vac line, it holds vac. Getting 'fountain' in rear of reservoir when applying brakes making lots of air bubbles in there, reservoir only half full, but that still can't be right. Engine idle picks up slightly when brakes applied. What am I missing? :confused: :confused: :confused:

[Bob Barry]

<blockquote>quote:</font><hr>Originally posted by arter:
Getting 'fountain' in rear of reservoir when applying brakes making lots of air bubbles in there, reservoir only half full, but that still can't be right.<hr></blockquote>

You've still got air in the Master cylinder, or a leak at the seal if you have a plastic resevoir; it should only pump straight fluid. Bleeding a master cylinder can be time-consuming, but if I understand you correctly, it sounds like you may need to do it again. :(

[onitsside]

i ended up buying a new master cylinder after trying to bleed two rebuilt ones. they look so shiny and new in the box, but rebuilt stuff is cheap for a reason. the new master cylinder was only 20 bucks more and it worked perfectly after bench bleeding. had the same frustrations with a rebuilt starter until i found an old 360 starter that hadn't been on a jeep in who knows how long. still works great.

[arter]

Thanks Bob. I'll try bleeding the master again and see what happens. Onitsside, I hear you. I've been having trouble getting the air out of the system all along. Had 150k on the master that was in there so went for a rebuild kit but that was 25 and a reman was 30. The new master at 'the boys' was 80, if I remember correctly. Probably nothing wrong with the original, just 'user error'. :rolleyes: