Brake upgrades

grumble wrote:Whatever,downunderxx asked a question and we supplied an answer,for anyones info this is a 1962 bug. To change to a dual system would still use the same pedal pressure.end of story.

Don't see how it would use the same pedal pressure for a start a single master cylinder has a bore diameter or 0.68" which has to supply to 4wheel cylinders of diameter .87" and .75".
where as a dual master cylinder has a bore diameter of 0.75 "( which is larger) and 2 separate pistons in the bore one circuit supplys the front calipers of daiameter 1.5" the other supplies the rear wheel cylinders diameter 0.68"so a dual master cylinder is like 2 single cylinders in one.

So by putting a dual master on a single circuit system will supply more pressure to the wheels cylinders and calipers. Because the bore is larger and there is more fluid in the bore being supplied to the system.

Pressure = surface area x Force.

End of Story!

downunderxx wrote:Hi Guys, I have completed a disk brake conversion with the spindles and standars kit on the front of my daughters 71 beetle. I'm still not overly impressed with the braking, and given this will be her 1st car, I would like it to be as safe as possible. Am I missing something, is there a master cylinder change or something to be done to match the disk brakes that would improve the overall performance?

Make sure the rear drums are adjusted up correctly and evenly. check the front calipers aren't sticking . Bleed the system of any air and make sure the free travel of the brake paedal is set correctly. if all this is ok and you still have problems try clamping one brake line off at a time to isolate which wheel is causing a problem. As some one mentioned check the brake hoses as these can sometimes swell under pressure. If you have a single circuit master change it to dual circuit master. and if you already have one of these maybe one of the circuits in the master is leaking. Also make sure that the bleed nipples on the calipers are pointing up.