Wilwood brake questions

[bruno]

I am wanting to use the Wilwood reverse clutch and brake pedal system on my 37 Dodge pu. I must use a reverse system because of header interference. Cannot be mounted under the floor due to space limitations. I have never used a system like this before so I have a bunch of questions for you brake experts.
1. Is this system ok to use in a hot rod?
2. Since the brake set up uses 2 MCs with a balance bar do you still need a proportioning valve?
3. Will it work with GM metric discs on front and S-10 drums on rear?
4. If it will work, what size MCs should I use on the discs and what size on the drums, 3/4 7/8 or 1 inch?
5. Would I just need a residual valve on the rear drums?
6. The ratio on the pedal assembly is 6.25 to 1, does that have a bearing on MC sizes?

That's all I can think of. Will be patiently waiting for you responses[P

Thanks in advance,

 

[JBailey]

I can't answer all your questions, but I can answer some. It will work with gm metric calipers just fine and I would guess 1 inch bore for the disk and 7/8 for the drums with a residual valve. The balance bar should work the same as an add on proportioning valve. The pedal ratio should be about the same for any vehicle. I hope that helps some.

 

[donsrods]

Bruno, wish I could answer your questions, but I just don't know. However , I can see no reason why you can't use that setup. My Son is going to run the automatic version of this pedal assembly in his Mustang and he just got it the other day. Nice piece and very compact.

I would call Wilwood with your questions, they should know.

Don

 

[Old Iron]

1. Yes it will work great
2. No proportioning valve needed. The brake bias is set by adjusting the balance bar from one side to the other. Set the bar in the middle of it's travel, drive the vehicle, make a simulated panic stop, if the rear tires slide, adjust the position of the bar towards the front m/c, make these stops and adjustments until the rear tires quit sliding under this type of braking.
3. Yes
4. I agree on the 1" m/c front, 7/8" rear.
5. Since the master cylinders are higher than the wheel cylinders no residual valves needed.
6. Pedal ratio definitely has a bearing on master cylinder size. Since it is set at 6.25 to 1 just go with the recommendations of the manufacture as Don mentioned.
The smaller the m/c the less pressure you have to put on the pedal. You can go too small and the travel of the pedal will become to much.

 

[bruno]

I called Wilwood and they advised 3/4 MC for front and 1 MC for the rear, that sounds completely backwards. I called again, got another tech and he said 3/4 front and 7/8 rear. Front calipers have 2 3/8 pistons and rear wheel cyls are 3/4. Old Iron what do you think.

Come to think of it I guess I need more pressure to the front because it does the majority of the braking. A smaller MC would apply more pressure wouldn't it?

 

[JBailey]

Yes the smaller will push more pressure but, the calipers require more fluid. I'm confused now lol, what they told you is backwards from everything I've read and seen.

 

[BlueNorther]

the discs require roughly 2.5 times the pressure that drums do.

discs have no built in self generating power multiplication like drum brakes.

you don't need much volume with discs as the pads only back off the rotor surface a few thousandths of an inch.

and you should always run a 10# residual valve with drum brakes as it keeps the large lips of the cups sealed to the inside of the wheel cylinders, the disc side can go without the residual valve.

I would use the recommended 3/4" / 7/8" sizes, and the adjustment bar towards the disc brake MC on a 60% bias. adjust the bias as mentioned above, DO NOT ALLOW THE REAR BRAKES TO LOCK UP BEFORE FRONT BAKES DO, SPINOUT STOPS ARE ONLY COOL IN THE MOVIES.