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Mon Oct 19, 2009 6:25 am

Well my master cylinder has been leaking and I decided it was time to do a brake job. I've got a 70 baja, with stock rears and what I assume are ghia discs in the front. Rears were ok, just needed a little cleaning up and adjustment. Pads were very worn in the front so I replaced them. Bought a cheap ass chinese master cylinder that didnt work because the nut would bottom out before the line would tighten up. Bought another master cylinder after that. Fun, got to practice replacing master cylinders.......on to my issue.....the left front is hanging up bad. Do I need to replace the master cylinder with a new style that has the proper residual pressure valve maybe? I mean if its set up for drum in the front I would assume it has a different residual pressure built into the master. Wierd though its only one caliper hanging up. I also noticed that even with the pedal released it has about 6V at the brake light switch, 12V with brakes applied and then backs down to 6V when I release the pedal. There IS freeplay at the brake rod as well. Any ideas?

Mon Oct 19, 2009 8:36 am

If the front brake line from the m/c runs into a T and then feeds left and right calipers, your rubber line has probably collapsed on the left side.
They act like a check valve when that happens, pretty common.

Mon Oct 19, 2009 9:43 am

it doesnt have a "t". It has 2 outlets for the front brakes, one on top and one on the left side. Makes sense though, maybe that hose has collapsed.

Mon Oct 19, 2009 10:00 am

Essentially head end of single master cylinder is a 4 way tee (?)... If you are having trouble with just one brake, its has to beyond master cylinder, so its either hose or caliper/cylinder.

Dale

Mon Oct 19, 2009 10:12 am

alright, well I guess what I'll do is crack the line at the master cyl. and see if it still holds pressure. Then I'll loosen the bleeder screw. If it holds still at the master but then the bleeder releases the pressure I'll assume its the line collapsed.

Wed Oct 28, 2009 10:05 am

just wanted to post up the solution, it was a collapsed rubber line. I loosened the line at the M/C and the caliper was still compressed. Loosened it at the caliper and it released. Went ahead and replaced both front brake lines. Thanks for the help guys.