singledownloop Reader
10/15/17 8:19 p.m.

What m/c can be used for my manual brake system?It's for 4 wheel disc brakes with single piston gm metric calipers.Trying to find the ideal bore size for my system.

sesto elemento
sesto elemento SuperDork
10/15/17 9:07 p.m.

Depends on diameter and number of pistons.

singledownloop Reader
10/15/17 9:29 p.m.

 A single 2.38" diameter piston in each caliper.

Streetwiseguy UltimaDork
10/15/17 10:43 p.m.

That is a, or maybe WAS a pretty commonly used setup in short track stock cars.  Might be able to do some research in that direction.

singledownloop Reader
10/15/17 10:58 p.m.

In reply to Streetwiseguy :

It actually still is commonly used in stock cars.A lot of the "hot rod" style suspension kits use them as well,thank you.

loosecannon Dork
10/15/17 11:50 p.m.

The Wilwood Tech line guys are very good, just call them with all the info on your car

tr8todd Dork
10/16/17 6:05 a.m.

Math wise 1 and 1/16" is about right.  A 1" will give you a softer pedal with a little more travel.  1 1/8" will be hard and have little travel.  Whether to go 1 or 1 and 1/16 will depend on whether you have a booster and what the pedal ratio is.  For the final math you need to figure those out and then calculate your maximum braking force based on a 200lb push on the pedal.  You don't want more than 1400 psi or so on the brake lines, and you don't want to have to press so hard on the pedal that you distort the firewall.  The problem you are going to run into with the same size pistons front and rear, is that you are going to have to proportion the rears down a lot.  Most Wilwwod setups will run  four 1.75 pistons per caliper in the front and four 1.38 pistons in the rear.  Google brake master cylinder sizing and you will find several good sites that explain it better than I can.  Mark Williams is a good site to start.

singledownloop Reader
10/16/17 7:50 p.m.

tr8todd Thanks for directing me to Mark William's website.As you know it has a lot of info that can be hard to find.

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