91 249sx strange brake problems PLEASE HELP

[Liquidus]

okay, i have a very strange brake problem w/ my 91 240sx w/out ABS. There is a strange problem with brake pedal resistance, as well as braking power.

First, the resistance in the pedal seems to be random, and so does the dead zone of the pedal, sometimesi can push it 1 - 2 inches before i feel resistance, others it about immideate.

As far as the brakes actually working, sometimes they feel strong, others they don't.

The master cylinder was replaced about 4 months ago, and ever since then the pedal was kind of soft, but not crazy like it is now. Howeve, i just replaced the pads and rotors, so maybe this made an old problem show itself.

I'm completely stumped as to what would cause this. Seems like if the brakes just had air in them in wouldn't be this random.

Please, please help. The first drift event of the season is next weekend.

Thanks,Rob Louie

[JeromeS13]

First thing I'd do is do a good bleed in the correct order. Second thing I'd do is find out if your brake fluid is contaminated with water somehow.

-Jerome

[Cyclemut]

Make sure the guy that did the replacement of the MC used the right fluid. If he tried to "upgrade" you, knowing that you drift, he might have ended up hosing you.

I believe you should be using a DOT3 or 4. You can use the synthetic versions, but they still have to be the correct DOT#.

Otherwise, start cracking all the connections, one at a time, with someone pushing on the brake pedal hard to see if you get any air at the MC.

Then bleed the system. It might prove better to get a power bleed from a reputable shop. A brake system flush with a power bleeder, using good quality brake fluid (not NAPA brand fluid, but something like BG or even Valvoline) would do wonders for something like that as well. Especially if you're drifting.