I have the S-10 manual master cylinder pushing vented LC brakes (4-piston jobbies) up front, and the Monte Carlo calipers in the rear, no e-brake.

Question is this: Without going to power brakes, is there possibly a different M/C that you all know of that could be swapped in that would provide more braking force for a given amount of pedal push?

I looked into re-drilling the hole in the brake pedal further up, to allow for more lever action, but it doesn't appear I could really go up much at all, so I think that's out.

The cruiser stops fine and strong, but on steep hills, or especially winching someone else, I find it hard to keep it stopped. I'm looking into a driveline brake (more than likely from Jess @ highangle) to help the 40 stay put, but I'd like to focus on the brakes first.

Summary:
1: I'm guessing I want to go to a smaller bore MC, so more pedal travel is required to move the same amount of fluid? my pedal hardly moves now.
2: What's the bore on the S-10 master?

If the pedal dosen't travel very far you are probably getting enough fluid to the calipers, maybe you need to lengthen the pedal for more mechanical leverage. Are all the calipers holding ?
maybe one set is clamping before the other...How does it react when you hit the brakes hard on a gravel road ?

sounds like its working, eat yoru wheaties! jiMMy

Jimmy - :flipoff2: But yeah, I'm not a big guy.. 6', 180lbs.

The brakes work awesome... I can adjust the proportioning valve how I want it, can lock up all 4 on a dirt road. there's nothing WRONG with the brakes, I just want more power to the wheels without going hydroboost or power assist...

It's gotta be something with MC bore size...

there are current threads covering this.. Go get power breaks.. and search the threads under BIGDUDE

i run a master cylinder from a 74 corvette with 4 wheel manual disc brakes ($35 at autozone) it has either a 1 1/16 or 1 1/8 bore and moves a lot of fluid. i run a dana 60 front and disc 14 bolt reat with chevy calipers, and i cannot put the petatl on the floor. if you have enough leg strength, then this is the answer. this set up works great for me, i can lock up all 4 at 60 mph, but my girlfriend is not strong enough to.

i hope this helps

Thanks Heep86... That's the kinda info I was looking for...

And what part of "I don't want power brakes" don't you get CJ6? :flipoff2: Yeah, I've been followiung that thread, it's kinda what got me thinking about mine... But I really wanna stick with manual brakes.

WTF !!!! Stop buying bin lahoodin stickers for your 2wd p/u and throw down for some brakes man !!! :flipoff2:

there is a few options.... your right on about the smaller master. You may have a power master on there now.

I had an s-10 that i upgraded from manual brakes to power and the masters were different.... I swaped out the whole peddle assm and if i recall the post that the master rod sliped over was about 1" or so lower, than before giving some more advantage. Was never as good as the pwere brakes though...

why not throw on a booster? need help cutting some junk out of the way?

Some of the GM 4wds or other cars had real small diameter boosters... might can fit.... or consider slapping a hydroboost on there and run it off your GM steering pump... Those work the bomb !!! would need a diferent master for that though.....

-yag

a booster does not add to your braking AT ALL
just makes the pedal easier to push

Originally posted by Eskimo
Question is this: Without going to power brakes, is there possibly a different M/C that you all know of that could be swapped in that would provide more braking force for a given amount of pedal push?

I looked into re-drilling the hole in the brake pedal further up, to allow for more lever action, but it doesn't appear I could really go up much at all, so I think that's out.



I have this setup and found that drilling the pedal LOWER increased the ratio/leverage and solved my problem. Yes it is a firm feel but with the rod lowered on the pedal it holds much better with the same leg pressure.

I like the Corvette mc suggestion also.

Hrmmm.. I could go down, but then the rod angle would be kinda funky unless I move the whole M/C down...

Maybe I'm being too detailed:

My pedal feels like a block of wood, but brakes work. I'm *NOT* running out of pedal..far from it.. I have very LITTLE travel..and want the brake pedal to move when I push it.

Want to be able to put more pressure to the brakes maintaining the same brake effort.

Do I need a smaller, or larger bore M/C? I've been told both... :mad:

if you have a firm pedal with little traval, id swap to a smaller bore.. this will create more hydrolic presure at the same amount of force, the down side will be slightly more pedal travel. i belive you have a 1" bore right now, swaping to a 7/8 shuld do what you want. belive it or not i have a friend that has of all things a samuri m/c on his 54 willes w/ 4 wheel disks using the big gm calipers and its killer..

You keep using different expressions, so I'm a little confused.

Sometimes you say the brakes work great, other times you say you want more "power", other times it seems as if all you really want is less effort required.

I'm going to assume the latter, that the brakes work well (have enough stopping power) but you wish the effort required was not as great.

There are 3 things you can do:

1 - add a booster of some kind, vacccum or hydro. You said you don't want to do this, and I understand. I have manual brakes in the buggy because I like the brake effort being identical with engine off or on.

2 - change the pedal ratio -

To figure pedal ratio:
divide the distance between the pivot and pedal centerline by the distance from the pivot to the MC.

Pedal ratio should be about 4 to 1 for power brakes, 6 to 1 for manual brakes. Making the ratio greater, will make the pedal easier to push. So for you you'd want to increase the distance between pivot and pedal without altering the distance between pivot and MC..which generally means lengthening the pedal, or moving the pivot AND MC up.

3 - use an MC with a smaller bore. You certainly don;t want a MC bigger than 1" with manual brakes (unless you don;t mind a hard pedal)....and even 1" is pushing it.

Here's some interesting info:

Assuming a pedal ratio of 5:1 - Note that going from a 1" to 7/8" MC bore increases the pressure to the calipers by almost 50% !!! So, this also means that if the 477 psi out with the original 1" bore was sufficient stopping power (which seems to be your case) then the smaller bore would allow you to generate that same pressure with LESS lbs input...i.e. NOT SUCH A HARD PEDAL


THE EFFECT OF PEDAL RATIO AND BORE SIZE ON HYDRAULIC PRESSURE OUTPUT
Pedal Ratio Bore Size lbs input PSI out
6:1 1 1/8 75 453
6:1 1 75 573
6:1 7/8 75 748

5:1 1 1/8 75 377
5:1 1 75 477
5:1 7/8 75 623

4:1 1 1/8 75 302
4:1 1 75 382
4:1 7/8 75 499

I read that other thread - and ther was a lot of bullshit and misinformation there, as well as some terrificly large ego pumping
:eek: :eek:

Perfect Bill! Thanks...

It's hard to describe the brakes... they work (i.e. nothing is broken, sticking, etc), but I have a very hard pedal with little travel.. so I want more travel so I am able to get more force at the calipers.

Now for the hunt for a 7/8" bore MC begins!

Originally posted by BillaVista

Assuming a pedal ratio of 5:1 - Note that going from a 1" to 7/8" MC bore increases the pressure to the calipers by almost 50% !!! So, this also means that if the 477 psi out with the original 1" bore was sufficient stopping power (which seems to be your case) then the smaller bore would allow you to generate that same pressure with LESS lbs input...i.e. NOT SUCH A HARD PEDAL



As long as you are moving enough volume. Disc brakes are low pressure High volume, a smaller bore MC may not provide enough fluid to move the calipers all the way and result in pumping. I run a single chamber 1" bore Wilwood cylinder with 4 wheel chevy brakes. I have enough easy braking force to stop my motor in 1st gear low range (85:1)

I have a very hard pedal with little travel.. so I want more travel so I am able to get more force at the calipers.

Still not sure if you want more force, or just the same force with less effort required. If the pedal is really hard ...it can be very difficult to generate all the possible force the system is capable of, because the input required is so high.

Either way - I think the smaller bore MC is a good start. Of course, you don't want to to go too small, otherwise you don't push enough volume for a firm enough pedal !

Quote from Wilwood:

"The goal is to select a master cylinder system that supplies sufficient fluid volume to provide a firm, responsive pedal, while generating enough pressure to stop the car comfortably. "

And of course, for best performance, everything needs to be well matched, from pad and rotor materials, to MC size, and all the valving (residual, combination, proportioing valves etc.)

What valving does your system ahve?

the only valve in my system is a summit adjustable proportioning valve...

You hit the nail on the head... my input force required is so high that I cannot generate all the force capable ...

I'm mostly Italian..can't communicate without my hands! :D

With all the pedal travel I have that's unused (because of the high effort), I doubt I'll go too small... 7/8" seems like a good start.. might even try a 3/4 if one falls in my lap. Heck, if it don't work, I put something else back in!