Bleeding brakes

[Ekustom]

Well I just finished lowering my car(71Z) w/ tokico springs and struts,replaced all my bushings w/urethane and put new wheels and tires on it.Now, what I thought would be the easiest thing to do ,bleeding the brakes is giving me a hard time.I've bled them ,till I only get fluid out of the bleed ports but,my pedal still goes to the floor.Is my Master cylinder bad?It's not leaking externally.

[2ManyZs]

You may still have some trapped air in the system.

Try this before you give up and buy an new master cylinder. Fill both reservoirs and bleed the master cylinder first. Bleed off nearly a full reservoir out of both reservoirs. Re-fill the reservoirs and then bleed the wheel cylinder furthest from the master, the right rear. Re-fill the reservoir and then bleed the left rear. Re-fill the reservoir and cap it off.

Now do the right front the same way, then the left front.

Be careful while you are bleeding that you never let the reservoir get too low as you will pick up air and have to start all over again. Always try to have at least a 1/4 inch of fluid for the bottom if possible, or never let the master reservoir go below half full. It is possible to pick up air even if there is a tiny bit of fluid in the reservoir while you are pumping the brakes.

I was taught you should do the wheel cylinder furthest from the master in that the fluid has the farthest to travel. Once you are sure all the air is out of that line, you move to the next furthest.

Try it one more time and see if that helps, if not, then the master cylinder may be to a point that replacement is the best alternative.

Always double check the bleeders before moving to the next wheel that they are completely tight, or else you will draw in air into the system. Then you are back to square one again.

[ZmeFly]

but 2 many has already covered all the bases.

pay attention to the master young grasshopper

[santamaus]

Question--

The diagram makes it look like one of the reservoirs feeds the front brakes, and the other the rear. Is there some crossover that I've missed? Does it reside in the brake cylinder assembly itself?

Thanks,
Chris

[2ManyZs]

Yes, one reservoir feeds the fronts and one feeds the rear brakes. There is no cross-over, they are two separate circuits after the master cylinder. The master cylinder does only use one piston to control them both however. You have a proportioning valve that controls the amount of front/rear brake bias, more pressure to the front brakes because they are the ones that do the majority of the braking.

When you are bleeding the brakes you can see that there is no cross over, when you bleed the rear brakes you only draw fluid from one reservoir.