The Stovebolt Site Forums The Shop Area The HiPo Shop second try on s10 brakes

I thought /hope that if I reword my previous question I mite get an answer to my dilemma, so here goes.
I'm putting a 4wd s10 rear end with disc brakes under my 3100 it's plumbed for 3/16 o.d brake line. I'm using an s10 front end
with danford crossmember under the front . The set up I have is from about an 04 s10 . It has 2 piston calipers.
It uses 1/4 inch o.d tubing . The master cylinder is set up for 3/16 o.d lines. Needless to say I'm concerned about
everything working when I'm done. What do I need to make my brakes work properly? Sincere thanks

You did not mention which master cylinder or vacuum booster you're using, or the year of the 3100 you're modifying. The original equipment master cylinder WILL NOT work with the brake system you're describing, and if you're mixing front and rear brake components it's entirely possible there won't be a suitable master cylinder available. The diameter of the brake lines is totally irrelevant. It's the diameter and stroke of the master cylinder piston and the amount of fluid displaced to operate the front and rear brake cylinders you should be concerned with. Lots of physics and engineering by the manufacturers goes into designing a safe, effective brake system, and that time and money would not be spent if any old collection of parts would be adequate.
Jerry

7 inch booster/M.C. got it from speedway . maybe my question is, will dual piston calipers on front need more m.c. capacity than rear single piston caliper?
would proportioning valve solve issue?

A proportioning valve just modifies the front/rear bias of the fluid flow to prevent rear wheel lockup by directing more fluid toward the front, or slightly delaying the application of the front brakes to allow steering control on slippery surfaces such as ice or snow. The diameter of the master cylinder bore in comparison to the caliper piston(s) is going to affect the pedal stroke needed to move enough fluid to get the rear wheel cylinders and front calipers applied. A too-small MC bore is going to result in a long pedal stroke and/or inadequate braking. You're going to need to do some math homework on the fluid volume to determine whether your collection of possibly mismatched parts is going to be safe and effective. Good luck!
Jerry

Charles, my opinion and it's my opinion only is, hook it all up, bleed the system and see if it works. This stuff is being done all the time and usually it works just fine. Jerry, is right as usual but sometimes right just don't get er done!

You might have to trial and error this one. The math would be to find the bore and stroke of the master cylinder to see what volume of fluid it moves in one stroke. I would divide this in half because a full stroke would put the pedal on the floor. A search shows a 2004 S10 to have discs on all four corners which is a two sided sword as discs stay much closer to the rotor than shoes to a drum but then the caliper bore is much bigger than a wheel cylinder bore. A KISS example is a MC with a 1" bore and 2" stroke moves 1.57ci of fluid per stroke of which I'd use 1ci to keep the pedal off the floor. Now IF you can figure the volumes of fluid needed ( pi r squared h) for each caliper to move the pads against the rotors then you will know what size MC is needed. Trial and error is to put it all together, bleed, and see what it has brake wise. If air all out and pedal too low get a bigger bore MC. Too big a MC is like pushing against a rock with little braking happening. As far as line size the above mentioned 1.57ci of fluid per stroke happens in any size line.

Ok, heres my suggestion. If the braking system you are using is all from the same truck(frt and rear) Then try to use the master from the same system. If that is not possible find out what the bore sizes are in the oem master and duplicate that. There are a million masters out there that, with an adjustable push rod can be made to work in most cases. Otherwise I would have to agree with Martins statement of a bit of trial and error, sometimes things just work out.

Good answers. I totally agree.

1. If you are using all the stuff from the S10, you have no problem. If not, buy the needed S10 parts. (DaveMcK38)
2. Try it and see how you like it. Not a big deal. (Martin)

You have adjustability in linkage rods, You can add supplemental valves if needed. You can't do the math. Build it, plumb it, bleed it and try it.

Two piston calipers are not a factor in this discussion.

3/16" or 1/4" tubing, or both. Does not matter.