No brake pedal? Help

[jafanan]

Ok so on my mk1 sr i was running standard **** brakes but after them seizing and sticking i was constantly stripping them and freeing them up

Lately after the car not being drove for a week the brake pedal was very soft and eventually went to the floor after a few days

Decided id change the calipers to corsa sport and got them fitted and went to bleed the brakes but couldnt get a pedal fr nearly an hour, even though they were eventually bled with no air whatsoever in the pipes

Pedal still going to the floor

Good amount of fluid being pumped to each caliper so cant see it being the servos fault

Fitted the standard calipers back to see if that would cure it but no difference
Any ideas?

[Markd89]

Callipers on the right way round ? Bleed nipple at the top

[yellow_seh]

take the drums off and check the rear wheel cylinders make sure they aren't leaking fluid, if thats all good i would say your looking at the master cylinder. i have had several old vauxhalls do the same thing usually whilst going down the road, the seals get weak and turn inside out.

[jafanan]

Yes calipers on the right way

Tried another servo i had spare and made no difference, altho im trusting it was ok

Is there any way of testin the servo?

Could try the drums but cant see it being the problem, had the drums kff a week ago to check and all was ok

[mowgli]

1. the servo has precisely shag all to do with the hydraulics on the brakes, it just assists the master cylinder to make it easier... sorry a bee got in my bonnet there...

2. most brake problems on novas are caused by rear cylinders. if they are massively out of adjustment, cos the self adjusters simply don't work, when you press the pedal, the cylinders move enough to nearly take up the whole stroke of the master cylinder, so it doesn't matter how often you bleed them, they need to be bang on with their adjustment to work.

3. get a gunson pressure bleeder. they aren't much money. also invest in a brake hose clamp. mole grips will kill them.

4. when bleeding, start at the furthest point from the master, ie. the rh rear. then lh front, then lh rear, then rh front. then repeat this till the pedal feels soloid again.

its not that bad a job

[Nobby]

I once changed rear brake pipes on a Jag at work and went to harsh on thr pedal trying to bleed tgem up and it fuked tge seals in the servo so it "could" happen. IMO take it or leave it lolmake sure yoj have got the nipple at the top on calipers and as mowgli says start furthest away andbeed the system again, i usually crack the nipples off till fluid runs out then pump tge brakes but dont go mad just slow and soft.

[Andy]

I always start the pedal by hand gently 1st to be sure not to invert the seals

[jafanan]

Thanks mowgli

Whats involved in adjusting the rear cylinders or testin if they need replaced?

Thanks for your helo everybody, im not fully clued into brakes

[marc69]

To adjust the rear brakes, take the hub off then you'll see the self adjusters near the top which never work. basically you can use a screw driver or pliers to turn the bit with the notches that the adjusting lever is supposed to pull down. There is probably a better way to do this but that's what i do.

I can't rememebr which way is to tighten and which way is to slacken but you'll see it move outwards to obviously tighten the brakes.

There is probably a method for the next bit but, I just tighten them a bit, put the hub on, press the brake pedal a few times to centralise the brakes release the pedal and see if the wheel is free. Then adjust further and do the same, until the rear hub is just rubbing, then release by one notch to ensure they are tight but not binding.

I assume you have the handbrake adjusted reasonably tight too?
I hope this helps