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Disc Brake Q&A



I have drum brakes with 14" wheels now.. If I change to disc brakes can I keep the 14" wheels? In most cases no. Typically you will need to go to a 15" wheel when converting to disc brakes.
Why are disc brakes better than drum brakes? Disc brakes are not subject to fade from heat or water. Disc brakes also do not drift out of adjustment.
Which calipers are better 4 piston or single piston? Single piston calipers are now the standard. They are much more reliable since there's only one piston which could possibly leak...not four.
Do disc brakes require more pressure than drum brakes? Yes.
How much pressure is needed for disc brakes? You will need at least 1000 psi to the front wheels.
Can I use my drum brake master for disc brakes? No, for two reasons. First you will not have enough pressure or volume and second the drum brake master will have a residual valve that will cause the disc brakes to drag.
Can I run disc brakes with a manual brake master? Yes. The bore size of the master can not be larger than 1" and your leverage at the pedal has to be greater than power brakes.
If I add disc brakes will I need a proportioning valve? Yes. The addition of a proportioning valve is a must. Without it your braking system will not operate properly.
Can I re-use the old drum brake valve when I change over to disc brakes? No. You must use a disc/drum valve.
I have converted my car to disc brakes and now I can't get a pedal. It goes to the floor no matter how much I bleed it.

Check the bleeder screw orientation on the calipers. The bleeder screw must be on top in the 12:00 position. If it is not you will not be able to remove all the air from the system.