Brakes nice and fluffy/spongy

johntheboy

Full Member
Mar 25, 2006
237
0
Teesside - North East
Well it's due a service anyway, and from looking at the service history I can't see it having a fluid change before which is pretty worrying but they seem very much more spongy under hard braking at speed than they used to be. I have done a search for but cannot for the life of me find a thread for someone who found an issue specifically for diesels to show where in the engine bay the brakes system was letting gas release meaning the brakes were'nt as good as they should have been, so if anyone could direct me to this it would be a help.

When was sat in traffic yesterday I pumped by brake until it was as hard as I could get it but when held it down it eased off.... as though gas was escaping (that kind of feeling) should this be happening or does it seem ok?

Cheers
 

Muttley

Catch that diesel!
Mar 17, 2006
4,987
31
North Kent
That's vacuum not gas - a bit more specific.

I think the thread you're looking for mentioned a non-return valve in the vacuum line to the brake servo. Can't find it right now though.
 

Willie

LCR Track car
Aug 6, 2004
8,939
1
Sunny Scotland
Sounds like the one, from the bottom of your intake manifold there should be a hose going to the master cylinder, this will be the one
 

ibizacupra

Jack-RIP my little Friend
Jul 25, 2001
31,333
19
glos.uk
Sounds like the one, from the bottom of your intake manifold there should be a hose going to the master cylinder, this will be the one

no

this is a diesel
no vacuum off manifold

pump driven off cam in the link posted above was that guys leaky vacuum source
 
Dec 6, 2008
612
0
Shropshire
A problem with the vacuum would cause a harder than usual brake pedal due to a lack of servo assistance as opposed to a spongy one.

pump the pedal up with the engine off until its solid then press and hold it and see if it drops slowly.
 

johntheboy

Full Member
Mar 25, 2006
237
0
Teesside - North East
A problem with the vacuum would cause a harder than usual brake pedal due to a lack of servo assistance as opposed to a spongy one.

pump the pedal up with the engine off until its solid then press and hold it and see if it drops slowly.

Did this with the engine off and it didnt drop, however it didnt get full hard, you could still press it a little before it was solid. Im guessin this just means the fluid could do with changing or the brakes need bleeding?
 
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