I want to upgrade my girls beetles single circuit master cylinder to dual circuit. What master cylinder from which year is required. It will stay drums all round but eventually get wide five discs at the front.

Thanks for any help. Damo.

Hi

A 1500 Beetle one. You can no longer buy a master cylinder to suit late drum brake bug.

So if you have a 1500 Beetle, a 76 Beetle or a 4 wheel drum brake 1300 12 volt Beetle you use the same one on all of those models.

Steve

nuthing there both 19mm and suit both systems

well the pipes may be different but if You are fitting dual brakes You need new pipes anyway...

LEE

if you look at what is available there is only single or dual circuit MC's. Both are 19mm bore size.

The MC does nothing with holding line pressure apart from allowing more fluid into the high pressure side to allow for pad and shoe wear. On old VW's the brake shoe springs are what return the wheel cylinder pistons to there rest position after the MC has been depressed. The return spring in the MC also is what draws back the caliper and wheel cylinder pistons due to it's internal return springs.

Go for a dual circuit MC cos then if a circuit fails you have some chance of stopping

I purchased a new dual circuit M/C disc front drum rear. So hopefully install that along with type 3 rear brakes also. Then add disc brakes to the front later.

you might be looking for those front discs sooner than later..........had dual circuit master with drums years ago.

Dual cct master has a lesser value residual valve as disc's want less residual pressure than drums (I believe 3psi compared to 10psi IIRC). I think you will have a long pedal with the disc master used on a drum system.

yeah What Matt said

Huh, didn't know that. Who says you don't learn something new every day

Hi
the brake test was done on steel ramps and the front/rear brake percentage comes up on a large digital readout up on the wall
[first time I've seen one] steel ramps are part if the machine..
Mechanic drives the car onto the flat steel ramps and hits the brakes..

from memory?? front had to be over 70% and mine was under..
it was raining so tyres were wet...

also tried it on a brake pedal readout machine but it also failed
Mechanic drove it all around town [in heavy rain] and said the brakes worked perfect..???

Lee

PS
they work even better with the rear braking more than 30%

otherwise the fronts just lock up..

UK MOT use a set of motorised rollers to place the wheels on. Braking torque is displayed on a large pair of dials to make sure each side is within a few percent for straight braking.

Hi

Lee the master cylinder you bought will most likely be for LHD.

Most brake test nowadays are conducted in the mechanics office.

My old 1302 with 4 wheel 4 spot brakes kept failing, the tester put it down to my cars heavier suspension not dipping under braking.

Steve

New NOS 1500 ATE master cylinder went on ebay last week

went for $132-00

cheers

LEE

was in Australia

Got one and installed it. Now waiting for resivoir and mounting bracket from CSP. Then pick up disc brake kit on friday.

seems to be a lot of left hand drive dual circuit master cylinders being advertised lately ( and not identified as such as well), did someone stuff up an order and bring a whole bunch of LHD units in to the country and is now off loading them everywhere ?

From what I can see they cant be used on right hand drive cars as the pipes will be took close to the tunnel.