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Thu Nov 19, 2009 9:57 pm

I've heard that you could put front size wheel cylinders in the rear brakes and it will accommodate the heavier wheel/tires? anybody done this or recommend for or against it?

Fri Nov 20, 2009 7:08 am

I have done it and it does make a little improvement.

Think scientifically, If you can make 2000 PSI (pounds per square inch) with your right foot/lever/master cylinder in the brake line (very realistic number in a brake line) this force is spread across the area of the wheel cylinder. The larger the wheel cylinder, (square inches) the more pounds it pushes on the brake shoe.

A 28 mm diameter wheel cylinder has 0.9544 square inches of area. Times 2000 psi will give a force of 1908.8 pounds pushing on the brake shoe. (0.9544 sq inch X 2000 lbs/sq inch = 1908.8 lbs)

A 30 mm diameter wheel cylinder has 1.0956 square inches of area. Times 2000 psi will give a force of 2191.3 pounds pushing on the brake shoe.

Keep in mind that you still have the same sweep area and the same fading/cooling charactoristic as the stock setup, just more force on the shoe.

Fri Nov 20, 2009 8:33 am

It probable gives you a lot stiffer pedal, but does not improve "braking power" much, it just make rears work more....

Only real cure for better braking is BIGGER hardware.....

I put type 3 rear brakes on rear of by dune buggy (for autocross racing) and it has about a 25-30% larger braking area and it really helps...

Dale

Fri Nov 20, 2009 8:46 am

Quote: It probable gives you a lot stiffer pedal, but does not improve "braking power" much, it just make rears work more....

Only real cure for better braking is BIGGER hardware.....

It does improve braking power, as I showed above in calculations. It just does nothing for brake cooling or swept area.

Buggy users have done it for many years. They just switch the fronts to the rear and vice-versa. Reduces braking power to the fronts and increases braking power to the rear. Buggies are so light up front the stock brakes can lock up under moderate and heavy braking so reducing the wheel cylinder helps.

A better cure as Dale states is not just bigger, but better cooling effected braking. Bigger does get better cooling because of pure mass. As a side note worth pondering, the Type 3 rear brakes use a larger rear wheel cylinder and makes the peddle stiffer.

But as the thread states, cheap upgrade and it works well as years have proven.

Fri Nov 20, 2009 10:05 am

accident investigation has taught me that 85% of the braking power on cars/pickups comes from the front wheels...

I do agree however that bigger hardware means better stopping power and less fade, just make sure that the fronts are up to snuff too...

just my nickel

Fri Nov 20, 2009 11:36 am

cool, i think that's what i'm gonna do. eventually i'm going to go to thing drums, just on a budget right now. thanks for you replies

Fri Nov 20, 2009 1:38 pm

I've run T-3 rears on my '72 that I had years ago,( some scum bag stole it) and they work great. The T-3 rear brakes did not have any problems locking up 31's. It's the best brakes for the bucks.

Fri Nov 20, 2009 8:59 pm

I fliped the wheel cylinders from the git go so can't compare. I do like the bias swap. The rears do the most and lock up first. I ran T3 drums till August 1st. I exploded the hub section out of the center and thus lost the wheel. Took out the arm so now I run 3x5's with Thing drums.

Fri Nov 20, 2009 9:12 pm

So you also take the rear cylinders and put them in the front?

Fri Nov 20, 2009 9:53 pm

Correct. Thats the primary reason it works so well. The larger rear tires are doing the work.