Standard Brake System Troubleshooting

[futura 3]

Hi,

 

I have trouble with my 1.9L standard brake system. The brake pedal is not sensitive at all and it seems that it starts braking only when pressed down by 1-2 centimeters. The servo seems fine (though I don't know how you test it) so I am thinking about a dodgy master cylinder?

 

The rest of the system needs attention, rear brake pipes are crusty and rear discs/pads are not in the best condition. The car also has some starting/idle trouble and a factory sunroof which I have read could affect the braking.

 

Could I have some advice on how to test the different components before I bleed it all, I'd rather have to bleed the brakes only once

[jim21070 2]

Servo is easy to test. With the engine off, pump the brake pedal until it goes hard. It'll take 6 or 7 or even more.

 

Start up with your foot on the brake. You should feel the pedal drop a little as the vacuum builds.

 

The sunroof works on vacuum and it is conceivable that a leak here could affect it but unlikely if the sunroof works OK. Do you hear a little hiss as you pull the sunroof release lever? A leak sufficient to affect the servo will cause idling problem too due to the air leak.

 

Master cylinder is OK if with sustained pressure on the pedal it does not move or slowly go to the floor.

 

Replace your crusty pipes and flexis. Flexis can collapse inside whilst looking OK on the outside and cause poor braking and binding.

 

The rear disk compensators (two hexagonal lumps under the bonnet in the rear brake lines) can give problems and cause the rear disks to have poor effort. Replacement is the only answer.

 

Strip all brake calipers, clean and replace pads and all should be fine. As they are all single pot types, ensure all calipers are free to slide.

 

Finally, note that the rear caliper pistons have to be retracted by screwing them in and not just pushed back like the front ones. This is due to the handbrake adjustment mechanism. Check that the handbrake cables are adjusted properly and that some gimp has not simply wound the nut on the rear of the handbrake lever to disguise a problem with the caliper handbrake adjusters.

 

Hope that helps a bit...

[futura 3]

It does thanks