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Brake Problem...Master cylinder??
vinnie_b23 - 5/4/12 at 05:56 PM

Hi all,
I know this has probably been covered and i have tryed a search but its easier to ask sorry.
I've bled my brakes for hours as i though it was an air problem but i cant stress how long i've done it for to rule this out.
Anyhow my problem is the peddle will go hard after 3 pumps then when you release pedel the resovoir level creeps up and the pedel goes spongy, hiting the floor when pressed again.
Everything is new apart from the master cylinder which is an ap lockheed and the to rubber hoses going to front calipers but i cant detemine which is the fault. I know i need to clamp the pipes which i didnt think of doing and i know this will indicate but does anybody know off hand?

vinnie_b23 - 5/4/12 at 06:06 PM

Sorry this should be in running gear

Ben_Copeland - 5/4/12 at 06:06 PM

If you've definately got all the air out then sounds like the master cylinder seal. Have you got all the calipers bleed nipple at the top?

vinnie_b23 - 5/4/12 at 06:14 PM

Hey i've got a mate called ben copeland haha
On that bombshell no i havent, they are on the bottom. So i'll swap the calipers around, will this cure?
Also if it helps they are type 16 ford capri calipers.

[Edited on 5/4/12 by vinnie_b23]

nickharding - 5/4/12 at 06:27 PM

Hi mate,

Defiantly sounds like a master cylinder seal.

Nick.

Ben_Copeland - 5/4/12 at 07:14 PM

quote:
Originally posted by vinnie_b23
Hey i've got a mate called ben copeland haha
On that bombshell no i havent, they are on the bottom. So i'll swap the calipers around, will this cure?
Also if it helps they are type 16 ford capri calipers.

[Edited on 5/4/12 by vinnie_b23]


Small World,

On the bottom means you wont get the air out properly unless you take the calipers off when bleeding. Better to swap them all round so everything at the top. Rebleed and go from there...

daviep - 5/4/12 at 07:55 PM

quote:
Originally posted by nickharding
Hi mate,

Defiantly sounds like a master cylinder seal.

Nick.


Please explain how you come to that conclusion? Doesn't sound anything like a MC fault to me.

Sounds like a perfect case of lots of trapped air, you pump the pedal and the gets compressed until it won't compress any more, then when you release the pedal the air acts like a spring and pushes all the fluid back to the reservoir as it expands again.

Davie

pmc_3 - 5/4/12 at 09:27 PM

quote:
Originally posted by vinnie_b23
Hey i've got a mate called ben copeland haha
On that bombshell no i havent, they are on the bottom. So i'll swap the calipers around, will this cure?
Also if it helps they are type 16 ford capri calipers.

[Edited on 5/4/12 by vinnie_b23]


As said by ben above bleed nipples should always be at the top. I've made the same mistake before and spent ages trying to bleed it, as soon as I swapped the calipers over had it bled in about ten minutes!

vinnie_b23 - 5/4/12 at 10:32 PM

Cheers guys, I'll try the calipers first thing tomorrow! I thought it would be something stupid but couldnt see anything obvious.
I've have literally spent hours bleeding these because i knew there was air somewhere and couldn't get my head around it.

nickharding - 5/4/12 at 11:04 PM

Missed the comment where the nipples were on the bottom. :O

vinnie_b23 - 6/4/12 at 09:49 AM

Sorted it! changed the calipers around, bled it and pedal stays firm. Thanks alot people, was pulling my hair ot about this and was about to order new master cylinder and hoses.
Definatly wont be making this mistake again.