I want to simplify the brakes on my toy and still improve performance.

I was thinking:

-Non-power brakes (I hate when it I lose the brakes because the motor isn't turning. Add a big time MC and give it a lot of mechanical advantage with a long throw pedal.

-Only one disk to brake the rear. The rear will be spooled. Take all of the crap from the outside of the axle off. Mount the only big disk brake at the t-case. (I have noticed that EVERYONE has too much brake in the rear and cannot not even proportionate it out right so I thought that reducing the braking to one disk would help this and then still be able to fine tune the system with a prop valve.)

-Upgrade the front to the vented disks and bigger calipers (help reduce the need for a booster).

-Use a residual valve to hold the shoes to the rotors (just plain needed).

-I can even fab up a simple hand e-brake to grip the opposite side of the rear disk.

On a side note I will be turning the SWB truck into a Long wheel base buggy without a front or rear clip. A skinny flatbed with tie down points is all that will be in the back. Lightweight will be the goal off this budget buggy.

So what issues can you see? :smokin:

-Non-power brakes (I hate when it I lose the brakes because the motor isn't turning. Add a big time MC and give it a lot of mechanical advantage with a long throw pedal.

-Only one disk to brake the rear. The rear will be spooled. Take all of the crap from the outside of the axle off. Mount the only big disk brake at the t-case. (I have noticed that EVERYONE has too much brake in the rear and cannot not even proportionate it out right so I thought that reducing the braking to one disk would help this and then still be able to fine tune the system with a prop valve.)

So what issues can you see? :smokin:

Seems like a lot of work for minimal increase in braking power. With simple mods like the upgrade rotors as you have mentioned, you will probably see enough stopping power unless you intend on installing some heavy meats.

As far as removing the brakes off the rear, installing a tcase disk, and installing a prop valve, that sounds like it would be the same amount of proportion tuning. Are you trying to get rid of rotational mass on the rear?

Reducing mass at the corners (as well as rotational mass) while retaining 4wd is a goal as well. I also want the mass to get close to the Centor of Gravity as possible.

A good disc setup is very simple and light. If one brake on the driveshaft was sufficient, don't you think good old Detroit would have done it by now? Breaking a driveshaft is not abnormal if you do really tough trials, what then?

This is going to be a trail vehicle/ DD not much in the way of rock crawling. The DS won't be in danger of getting wacked. Also the front brakes are around 75-90% of the total force in a vehicle that is sprung lightly. Plus if the DS brakes you will still have all three brakes working on the front axle assuming the t-case is in 4wd hi or low. The same goes for the rears being slowed by the front when it is in 4wd too.

Anymore concerns.

Edit: Detroit didn't build it. :flipoff2: Seriously, how many upgrades improve our little trucks that didn't get put in at the factory? Once more, how many things did they add that REDUCED performance? Example, solid rotors are the BOMB. Especially, when you have brake fade in about half the time of a vented rotor. That was OEM too. But they did save around $10 on each truck for like 6 years with production numbers in the realm of a half million world wide. That is quite a savings at the cost of a little performance.

In a word, No. I don't think if it was good it would get put on at the factory just because it is a better set-up.

First off- you need a SMALLER bore master to increase the mechanical (hydraulic) advantage.
http://home.4x4wire.com/erik/4runner/brakes/

Long throw pedal would help too, but I'm not sure how you'd do it. Not much room under there.

How often do boosters fail? Not often. "If it ain't broke, don't fix it." Sounds like you're trying to fix a problem that isn't really a problem.

As for when the engine isn't running, if you aren't pumping the brakes repeatedly, your booster should hold vacuum and still assist. If you wanted you could add a vacuum canister to increase the vacuum reserve capacity, like the one the ADD trucks come with on the fender for the ADD system. I've also heard of one guy on here who put an electric vacuum pump in (from a subaru I think?) that would maintain vacuum when the engine died, etc. Adds complexity, but if it died you wouldn't be any worse off than you are now.

A t-case brake isn't going to cut it on a street driven vehicle. Look at the guys running pinion brakes on their rockwells. They overheat them even screwing around off road. Your brakes need surface area to dissipate heat (like vented rotors). A pinion/driveshaft brake cuts that right in half.
I wouldn't want to run one w/o a spool in the axle either if I had to depend on it for the road. It could be unpredictable if/when the tires dont' have equal weight/traction otherwise.

You say to add a residual valve but you also say you are trying to simplify things. That's just the opposite, you shouldn't need one, so don't add one.

As for keeping your mass close to the center of gravity, that won't do you much good since it doesn't change the center of gravity. If you take weight from down low at your axles and move it up to your t-case, then you have actually raised your center of gravity. If you wan't to be less tippy (low center of gravity), then leave your axles as heavy as possible and lighten the load somewher up higher. Move your battery down under the cab, minimal cage work, etc.

As for keeping it simple, keeping it stock is about as simple as it gets since you can get parts used or new anywhere and if you maintain it, stock parts are very reliable. Even if you upgrade stuff using stock style parts (vented rotors, etc.).

Overall it sounds like you have some interesting ideas, but they sound like a lot of work for little or no gain, and they actually work against what you're after in some ways.

First off- you need a SMALLER bore master to increase the mechanical (hydraulic) advantage.
http://home.4x4wire.com/erik/4runner/brakes/

Long throw pedal would help too, but I'm not sure how you'd do it. Not much room under there.

I will have the room once I get rid of the dash. Thanks for the info on the MC.

How often do boosters fail? Not often. "If it ain't broke, don't fix it." Sounds like you're trying to fix a problem that isn't really a problem.

They weight like 5-10#s plus the plumbing and are mounted high.

As for when the engine isn't running, if you aren't pumping the brakes repeatedly, your booster should hold vacuum and still assist. If you wanted you could add a vacuum canister to increase the vacuum reserve capacity, like the one the ADD trucks come with on the fender for the ADD system. I've also heard of one guy on here who put an electric vacuum pump in (from a subaru I think?) that would maintain vacuum when the engine died, etc. Adds complexity, but if it died you wouldn't be any worse off than you are now.

You are right but I probably will need to pump the brakes a lot even if the motor dies. Just the nature of what my plan is. But I don't want more parasitic loads on the motor.

A t-case brake isn't going to cut it on a street driven vehicle. Look at the guys running pinion brakes on their rockwells. They overheat them even screwing around off road. Your brakes need surface area to dissipate heat (like vented rotors). A pinion/driveshaft brake cuts that right in half.
I wouldn't want to run one w/o a spool in the axle either if I had to depend on it for the road. It could be unpredictable if/when the tires dont' have equal weight/traction otherwise.

I said the rear would be spooled. I also said that it would be a big rotor, probably the same as the front rotors and calipers. You are right about needing to dissapate heat, about 20% of the total breaking but it will have more surface area than the stock drums (a 11" diameter x 1.5" surface on each drum, 12" x 2.25" on each side of the rotor, plus the surface area of the vents). Rockwells are like 1200#s each. My rig probably won't weigh as much as the axles much less a whole rig with Rocks.

You say to add a residual valve but you also say you are trying to simplify things. That's just the opposite, you shouldn't need one, so don't add one.

An all disk braking system needs around 2 psi to keep the pads in contact with the rotors so that you do not need to pump the petal to move the pads back out. Most Masters for this type of system have the valve built into it. It is passive.

As for keeping your mass close to the center of gravity, that won't do you much good since it doesn't change the center of gravity. If you take weight from down low at your axles and move it up to your t-case, then you have actually raised your center of gravity. If you wan't to be less tippy (low center of gravity), then leave your axles as heavy as possible and lighten the load somewher up higher. Move your battery down under the cab, minimal cage work, etc.

The whole rig will be lower than stock. The t-case will be on the same level as the drums. 20#s of drums on each side of the rear axle and being rotational mass will have a huge effect compared to 1/2 the mass inboard. Plus 40#s at the corners are harder to control in a slide than 20#s close to the CG. Also drums are unsuspended weight where the t-case is suspended.

As for keeping it simple, keeping it stock is about as simple as it gets since you can get parts used or new anywhere and if you maintain it, stock parts are very reliable. Even if you upgrade stuff using stock style parts (vented rotors, etc.).

Exactly why I am using as many stock parts (rotors calipers from Toys) as possible.

Overall it sounds like you have some interesting ideas, but they sound like a lot of work for little or no gain, and they actually work against what you're after in some ways.

I haven't been real clear on the use of the end product but for a typical PBB rig you are very much correct. This rig will be travelling roughly 5 times faster than most of the rigs on this board. It is just hard to ask for advise on a desert runner type vehicle here. Thanks very much for your help.



All comments are in Dark red. :D

Anymore comments before I let it die? Thanks again.

First off- you need a SMALLER bore master to increase the mechanical (hydraulic) advantage.
http://home.4x4wire.com/erik/4runner/brakes/

Long throw pedal would help too, but I'm not sure how you'd do it. Not much room under there.

How often do boosters fail? Not often. "If it ain't broke, don't fix it." Sounds like you're trying to fix a problem that isn't really a problem.

As for when the engine isn't running, if you aren't pumping the brakes repeatedly, your booster should hold vacuum and still assist. If you wanted you could add a vacuum canister to increase the vacuum reserve capacity, like the one the ADD trucks come with on the fender for the ADD system. I've also heard of one guy on here who put an electric vacuum pump in (from a subaru I think?) that would maintain vacuum when the engine died, etc. Adds complexity, but if it died you wouldn't be any worse off than you are now.

A t-case brake isn't going to cut it on a street driven vehicle. Look at the guys running pinion brakes on their rockwells. They overheat them even screwing around off road. Your brakes need surface area to dissipate heat (like vented rotors). A pinion/driveshaft brake cuts that right in half.
I wouldn't want to run one w/o a spool in the axle either if I had to depend on it for the road. It could be unpredictable if/when the tires dont' have equal weight/traction otherwise.

You say to add a residual valve but you also say you are trying to simplify things. That's just the opposite, you shouldn't need one, so don't add one.

As for keeping your mass close to the center of gravity, that won't do you much good since it doesn't change the center of gravity. If you take weight from down low at your axles and move it up to your t-case, then you have actually raised your center of gravity. If you wan't to be less tippy (low center of gravity), then leave your axles as heavy as possible and lighten the load somewher up higher. Move your battery down under the cab, minimal cage work, etc.

As for keeping it simple, keeping it stock is about as simple as it gets since you can get parts used or new anywhere and if you maintain it, stock parts are very reliable. Even if you upgrade stuff using stock style parts (vented rotors, etc.).

Overall it sounds like you have some interesting ideas, but they sound like a lot of work for little or no gain, and they actually work against what you're after in some ways.

This man is SPOT ON!!

Gnarls.

Anyone know how to convert from power to non-power brakes in a '88 yota 4x4? I need to move the master cyl out of the way. I figured loosing the booster was the easiest way to do that.