breaks again i give up

[rocky_679]

heres goes my brakes are useless.... so i changed shoes pads hoses n pipes disks callipers an plastic switch all new even changed the master cylinder an servo twice even changed valve reducing thing at front of the master cylinder heres what happens i bleed the brakes get good brakes from the foot pedal yet heres the crunch when i start the engine the footpedal goes to the floor an i have no brakes am seriously givin up what else can it be cos im gona crush her if i get more problems that will teach her[:(!]

stephen j dark

[John Clancy]

What about the rear wheel cylinders? Normally these stick and give you a solid pedal but perhaps the opposite is also possible.

Having said that, if it is the rear wheel cylinders you're going to be a little miffed having changed all the expensive bits!

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[rocky_679]

i put new rear cylinders on that is y im at a loss[?]

stephen j dark

[Jolyon39]

How are the flexible brake hoses?

There are three, one at each front wheel and a center one just in front of the Diff, under the car. If these are failing they might have gone soft and swell in size when you push fluid into them. Get someone to wrap their fingers around them to see if they can feel anything when you push on the brakes.... better still just replace them as they are over 30 years old now and will have deteriorated a lot. This actually happens to the clutch hose in our cars, a known fault in the clutch hose.

Also check that you have the calipers on the correct side as this may affect bleeding.

Hope this helps.

Jolyon

[rocky_679]

replaced hoses with new ones mate....when i bleed the system i have brakes when i start the engine the brake pedal goes to the floor an i have no brakes i cant grasp it ?????

stephen j dark

[staningrimsby]

I know you said you have replaced it Stephen but in my experience if you are sure there is no air in the system then the fault points to the master cylinder.



1980 2.0 DHC (soon to be 16v) - Polly.

[staningrimsby]

When your engine is running Stephen and you repeatedly pump the brake pedal does the pressure increase [?]

Also what type of brake fluid are you using Dot 4 \ 5 etc [?]



1980 2.0 DHC (soon to be 16v) - Polly.

[rocky_679]

no mate it doesnt [V]i think the crusher is calling her[;)]

stephen j dark

[staningrimsby]

You don't mean that [:)], this is all part of the classic car ownership process.[:)]

Was your replacement master cylinder a new one, second hand or a recon, did you recon it yourself [?]

Are you losing any fluid from the reservoir [?].



1980 2.0 DHC (soon to be 16v) - Polly.

[rocky_679]

master cylender was from shaunidawn with servo then i got 1 from robsport a used 1 had put new rubber seal repair kit on it an using dot 4 fluid no leaks from anywhere .....

stephen j dark

[staningrimsby]

If I am wrong i'm sure another member will correct me,

If there is no sign of fluid loss from the reservoir the only thing i can think of is that the fluid is bypassing the seals in the master cylinder.

Is your vacuum pipe from the servo to the inlet manifold ok as well.

Normally if your servo was at fault the brakes would be harder to operate when the engine is running as the servo provides assistance with braking.



1980 2.0 DHC (soon to be 16v) - Polly.

[rocky_679]

i checked the vacume pipe seems ok but havent replaced that 1 i thinki mite replace it just for piece of mind much appreciated guys as im stumped


stephen j dark

[staningrimsby]

Don't give up Stephen,

we will get there with you.[:)]



1980 2.0 DHC (soon to be 16v) - Polly.

[rocky_679]

thanks but at mo cars gettin me down bloody thing 1 thing after another [V] but they do say that its the final bits gettin done is the hardest point to get too

stephen j dark

[steve_1360]

Does sound a bit like air as one of the mot tests i've seen done to check the servo works is to start the engine with your foot on the brake and make sure it goes down a bit when the servo activates. One method of trying to find the air is to clamp all flexi hoses and see what that does. You can then remove one clamp and see which one makes the most difference and start there. I had real problems getting the air out of the front calipers when i had then to bits and resealed them.
Good luck.