Corsa brake problem

[ben doodar]

Afternoon all. I've got 1 for you to see if u can spread any gen on. My mates got a corsa b, when the cars not running and you press the brake pedal it dosnt really go hard it still feels quite spongy. When it's running there's no pedal at all it goes straight to the floor, He's put new brake pipes, flexis, and wheel cylinders on it. There's no leaks any where on the brake system. You can take the plasic pipe off the servo which goes to the inlet manifold and it sucks like....... You can imagine! He's had the servo off the car for a while with no fluid in it. Is it possible a seal may have dried up in the servo because of there being no fluid in it? He's bleed them up furthest away 1st.
I've spoke to a lad who said it maybe possible that the main seal in the servo has turned inside out due to pressing the pedal to fast when bleeding them up as this happend on his 106 rallye a while back.

He's tried on corsasport but there all useless (his words) so he's turn to a proper forum for help. It has 256mm brakes up front and std rear drums.
Thanks very much. X

[mowgli]

there are no fluid leaks. this means there are no leaks. the pedal will go down when the servo is working, as it is called servo assistance....

basically, he needs to make sure the rear brakes are adjusted up properly with very little play, then he needs to get some proper brake bleeding done. the easibleed air powered one is very good. or the small length of pipe & a mate who knows what he is doing method also works ok.

if this still doesn't work, then the master cylinder seals will be shot.

if the discs & drums are worn to the max limit, it will also affect brake efficiency.

[MK999]

calipers on right way up?

[mowgli]

/\ i always forget that one...

[craig green]

My guess is a goosed servo or the pad retainer springs on the fr calipers are wrongly installed.

I did this on my V6's a couple years back, the pedal would firm up from constant bleeding, but start the engine (servo assistance) & the pedal would just sink to the floor.

The springs looked right to me, but Lee noticed they were wrong, 2 mins later they were turned around, levered into place with a screwdriver & the problem had vanished. I think I had the most thoroughly bled brakes ever after that!

[edit] Start the engine & depress the brakes on & off. If the caliper appears to move, my guess is you have suffered the above. You could watch the calipers moving quite a lot when the pad retainers were on wrong. When on correctly you cant really see them move.

[mowgli]

can we please get this right.... the master cylinder is the bit with the small kunifer(bendy copper) pipes. the servo is the big round thing that bolts to the shell & has the hose from the manifold.
the master cylinder does all the braking, the servo just makes your pedal easier to push.

sorry, rant over

[ben doodar]

Thanks for the replys. The drums are adjusted correctly, adjusted till there binding and then slightly backed off. He has used the easibleed kit that connects to a spare wheel and he is very confident that they are bleed correctly. It's had new shoes also, and the discs and pads have lots of life on them as they were my old ones from my gsi. I'm putting it down to knackerd servo seals. Thank you.

[craig green]

mastercylinder seals pal.

have you read my advice??

[ben doodar]

Sorry I posted the above and then read your replys. Sorry mowgli Ill be more specific ie master cylinder, servo next time. I will get him to check what you have said Craig tonight. Thanks for the replys.