My master cylinder on my 1980 started to leak. I changed the cylinder and now the pedal travels further down (a lot) before the brakes engage.

I have bled the system many times... still cannot understand why the brake pedal has to go down like 2 more inches before the brakes engage.

Brake action feels solid...just more travel...

Any ideas??

 

How are you trying to bleed the brakes? If pressure bleeding (pumping the pedal up, holding and opening one caliper at a time), I would try to gravity bleed. Meaning just opening the bleeder and let the brake fluid seep out.

Starting at further from the master cylinder RR, LR, FR, LF.

If you are doing all this, and know that no air is in your brake system. Adjust the rod going from your brake pedal to the master cylinder. If you lengthen the rod a bit the pedal will engage sooner.

 

I have bled the brakes on 2 separate occasions... not getting any air bubbles. Pump pump pump...then open bleed till pedal hits floor.... close bleed and repeat.

I was thinking about adjusting the rod, but wondering if it has that much travel... I mean my brake pedal is going low.

It stops great...just the first few inches of travel does NOTHING!

 

adjust the push rod to your liking but leave some room for play. also, how are you bleeding it? hose straight a bottle half-way full with water? this is see the actual bubbles

 

The pushrod adjustment will cover quite a bit of pedal-movement range; it has angular advantage by being a lot closer to the pedal lever pivot point than the pedal is. Leverage, ya know.

 

Did you bench bleed it before putting it on the car?

Sometimes you'll get a bubble in the MC that just doesn't go away (unless you have a bleeder at the MC, though I've never seen an FB one that had it).

 

No I did not bench bleed the Master... I have installed a jillion master cylinders in the past and never bench bled them. I always ended up bleeding them once they are in the car.

When I bleed the brakes in the rear, and both fronts, plenty of fluid flows and it builds up pressure. No air coming out.

I will try adjusting the pedal... It will have to adjust a bunch, because you really have to push the pedal down.

 

Oh and this is on an SA22. It does have the bleeder at the MC.... I bled that also after being on the car.

 

Ahhh, I see then - good to know. Try the rod adjustment for sure then.

 

Yeah I think it is bled... I will try the rod adjustment..

 

Your booster may be going bad.

 

+1 on booster going bad.

 

I had similar trouble in my fb. But my pedal was also a tiny bit too squishy as well...

anyhow, the millionth time I bled the brakes, I decided to do a 2 man bleed. One to open/close the nipple on the calipers/drums, one pushing the pedal. But this time I pushed in the pedal super hard, and of course had person 2 close the nipple when I let the pedal out.

It turned out that pushing the pedal in mega fast/hard made the difference. Bubbles hidden in the lines that didn't move/floated upwards to escape, couldn't escape this time, and came out this time around. Problem fixed!

I don't know if this can help your situation, but it might.

 

When a booster goes bad it just gets super hard to push, the pedal travel isn't affected.

 

Hmmm..... strange, cause the fsm says to use the pedal travel in different situations as a test of the booster.

 

This is correct. I read his post incorrectly. My bad

 

Booster should have nothing to do with pedal travel. The "power" action is fine, just too much travel.

Both times I bled them i did a two man job... I feel they are bled. Maybe I will try a more aggressive way like Neanderthol suggests.

I will do the rod adjustment (when I get around to it)!!

 

Don't adjust that rod too much or you will get sticky calipers and burn up your brakes cruising down the highway. I tried that after experiencing a similar problem as you and it fried my brakes after a little cruise. Felt fine in the driveway then it just gradually built up more and more pressure on its own.

 

Hmmm, don't want to be mister obvious here but is the MC correct for the SA?
If the only thing changed is the MC, the pedal travel should stay the same.

If its air in the lines pumping it a few times will raise the pedal level. Thats a
good way to know its air. Also on the rears did you see a good flow of fluid? I ask
because the brake proprtioning valve can get stuck and not let you bleed the rears.
Usually bouncing real hard on the brakes a few times will recenter it and let
pressure get to the rear brakes again.

 

I *beleive* it is the right one. It looked exactly and has the same bore dimensions. It hooked up exactly the same.. Same Bleeder built into the MC that seems to only be on SA22 MC's.

If you pump the pedal, you do NOT gain pedal back. It is the same whether the 1st pump or the 10th pump.

Yes, I got good flow out the back end also.

I wondered the same thing... I am changing like for like.... why would things be any different!!

 

Problem solved!!! I adjusted the brake pedal and that completely repaired the problem!

All it took was adjusting the rod about 1/8 inch.. Divindriver was right!, leverage makes for small adjustments.

Now the pedal is even in a better position than before I did the master cylinder adjustment.

Instructions are in the FSM... so easy... just loosen lock nut with 14mm wrench... then screw out rod with small channel locks.... tighten lock nut...done!