56 Chevy Disc brake kit...can't get a decent pedal

[PT64POLARA]

Hey Guys. I installed an MBM (total crap by the way) fornt disc brake kit on my dads 56 nomad. I wanted to go with a better quality kit, but he insisted on trying the cheaper kit. Car was non-power original drums all around. I installed the front disc kit, with new 7" booster and duel master. I had the kit all installed and bleed with a nice pedal then had to fix a leaky line. I fixed the line and went to bleed them and got a crapped pedal. I drove the car yesterday and the brakes where there and the power assist was working, but the pedal was low. I re bench bleed the master, bleed the whole system again and its Worse!! Any ideas on the problem? Bad master? Bad proportioning valve? Bad rear wheel cylinders? (they look fine to me..no leaks) Thanks in advance for any advice.

[BlueBull]

I agree on it's totally crap. I bought a kit with front and rear discs from Matt's Classics. The sealings aren't rubber ones but plastic. After only one year and less than 1500 miles they cracked. When I complained they said they never heard of this before....

About your problem, I'm facing the same trouble at the moment. Spending days bleeding the system I finally used air pressure without success. Then I unbolted the emergency brake brackets and now the pedal is firm but way to low. I also realized the caliper must be unbolted and turned so the bleeder is on the highest position to bleed it completely.

Last year I had front discs and rear drums and that combo worked much better.

Good luck.

[Apogee]

Pictures would really help in a situation like this...or at least a link to the brake kit you're using. Some of the GM metric calipers are ported differently with respect to the bleed screws, so having the bleed screw at the top doesn't always work out well with all GM calipers.

Tobin
KORE3

[zman1969]

is it low and hard or spongy - spongy means you still have air in system as it compresses. if its hard then all i can think is the rear drums are out of adjustment. a bad master cylinder can leak - externally and internally-or bypassing - the symptom would be a sinking pedal. I dont believe the proportioning valve will affect pedal height. when/if you get a better pedal I'd jack car up and see if all of the wheels are holding -one at a time that will help you see if only fronts or rear are working. I'd do this before taking it on the road- safety first!

[PT64POLARA]

Thanks for the responses. I was able to get a really good pedal and the brakes are working great. First I adjusted the rear brakes, they were way off. Second I adjusted the pedal all the way out, I think it was returning all the way. And finally, one last bleed session. Thanks again guys.

[MuscleRodz]

I won't sell MBM brake kits anymore, but they do make decent boosters and mc's