[Clark Decker]

New rotors,pads,mastercylinder, and still crappy brakes. I built a stout 383 with a com cams 274 extreme energy cam. Only 15 inches of vacuum. I added a vacuum pump, brakes work like before, ok until you really stand on them. They don't get any better than ok. Next step is to get 12 inch brakes and spindles off a big chevy. My question, has anybody else done this swap, and did it work any better?

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old lefty

 

[chev64]

Clark, To give you any help with your brakes, we need more info on the car. Did you use a proportioning valve or just add the disc brakes? Give us more.

 

[Gene Chas]

I know bleeding is a PITA ( pain in the ...) but a bad or incomplete bleed will cause some of the same problems.

 

[Ratified]

If the master cylinder is not bled properly you'll never get it right. This can be done on the car by taking two old pieces of brake line with fittings that fit each port on the master cylinder. Bend each line so that when they are mounted on the MC the ends of lines extend almost to bottom of each side the reservoir. Have a friend pump the brake pedal slowly and watch the bubbles come up in the reservoirs. Add brake fluid as needed to keep the reservoirs full. When the bubbles stop, your done. Reattach the actual brake lines and bleed the rest of the system normally. Another problem that I have also seen is the use of the wrong actuator pin in the front of the booster. Drum have a long pin, early disc brake chevelles have an intermediate length pin about 4 inches,and later chevelles have a short pin, about 2.5 inches. The pin you need depends on the master cylinder you have. If the piston in the back of the master cylinder has a shallow seat, use the short pin. If the MC has a pocket in the rear piston about 1.5 inches deep use the intermediate pin. If you use the short pin in an early disc brake MC you will be short stroking the brakes, causing you to need to stand on the pedal to get enough stroke.

[This message has been edited by Ratified (edited 05-18-99).]

[This message has been edited by Ratified (edited 05-18-99).]

 

[chev64]

Clark, In response to your e-mail, the rear brakes should stop and hold the rear wheels when you step on the brakes. If they're not you may have non-functional rear wheel cylinders. To check this jack up one of the wheels,use a jack stand,pull the tire and drum and get a helper to push on the pedal some to see if the cylinders are moving the shoes.