12 replies to this topic

[jamesy]

Cant get the F***in thing to bleed! Took it apart and swapped the slave cylinder for one that i think is working. it aint seized and the old one definitly was.

Anyway, took out the master cylinder, emptied it of all old fluid and refilled it with some lovely new morris hydraulic oil.

now i cant get it to bleed, it seems like instead of sucking fluid in to the cylinder it doesnt....

Clutch down wedge bit of wood between it and seat - open bleed screw, *small puff of air and bubbles* - close bleed screw. - Raise and depress clutch pedal - open bleed screw *NOTHING*

Whats going on?

[Andrew O]

It sounds like a nackered slave cylinder.
Get your self a new one. They're only about £15

Andrew

[jamesy]

It did wok a year ago when it was on my other mini, its still springy, or are there internal seals?

[Andrew O]

Yes there are internal seals.
Just buy a new one, it should work then

Andrew

[bmcecosse]

Put a tube on the bleeder - and run it into a jar with some brake fluid (NOT 'hydraulic fluid ??!!) in it - then pump away fast down/slow up. It should clear..........

[jamesy]

Put a tube on the bleeder - and run it into a jar with some brake fluid (NOT 'hydraulic fluid ??!!) in it - then pump away fast down/slow up. It should clear..........

Should you use brake fluid in the clutch? its not just ordinary tractor hydraulic oil, cant rmember what its called, but its basicly really runny hydraulic oil.
I was told that the jar method doesnt work, there needs to be a non return setup of some sort, either closing the bleed screw or a non return valve.

[bmcecosse]

Well if you put in hydraulic oil - that's all the seals ruined in the master and slave now........ it is all designed for brake fluid. The flexi pipe will need to be changed too......

[Spitz]

Can't you have someone give you a hand? ( edit: foot..lol )
Much easier with two people if you don't have a fancy dancy bleeder.
May take several pump, hold, open, close, release cycles to get all air out.

( Hydraulic fluid ?? )

Edited by Spitz, 08 June 2012 - 08:44 PM.

[jamesy]

Ok, my bad, I AM WRONG.

will get the overhaul kits ordered. Lesson learned, all part of the mega learning cure that this mini is turning out to be!

[tiger99]

Mineral oil based bydraulic fluid will indeed ruin the seals and hoses. Even a trace of it is bad, so you should renew the rigid pipe too, as you will never get rid of the contamination.

But seal failure takes a day or two to happen. If it would not bleed immediately after filling, it is likely that the pedal is not returning fully, so the piston does not uncover the reservoir port, so no fresh fluid can enter the system. The pedal operation may need to be checked, and the master cylinder may need a shim under it.


Please read the relevant part of the Haynes manual very carefully before doing any maintenance. If that had been the brakes, you could have killed people, as with mineral fluid in the system, total brake failure within a few days is inevitable.

[Stella87]

Mineral oil based bydraulic fluid will indeed ruin the seals and hoses. Even a trace of it is bad, so you should renew the rigid pipe too, as you will never get rid of the contamination.

But seal failure takes a day or two to happen. If it would not bleed immediately after filling, it is likely that the pedal is not returning fully, so the piston does not uncover the reservoir port, so no fresh fluid can enter the system. The pedal operation may need to be checked, and the master cylinder may need a shim under it.


Please read the relevant part of the Haynes manual very carefully before doing any maintenance. If that had been the brakes, you could have killed people, as with mineral fluid in the system, total brake failure within a few days is inevitable.

Don't want to put a dampener on things but in my Haynes manual, under "Clutch Hydraulic System - Bleeding" it says to use "a tin of the specified hydraulic fluid" in the jar...is this bleeding a different system to the one you guys are on about?

My clutch needs bleeding and I dont fancy replacing the master and slave cylinder! Help is appreciated..

[L400RAS]

Don't want to put a dampener on things but in my Haynes manual, under "Clutch Hydraulic System - Bleeding" it says to use "a tin of the specified hydraulic fluid" in the jar...is this bleeding a different system to the one you guys are on about?

And then in section 0.16 - lubricants and fluids, it specifies for the clutch - Dot4 brake and clutch fluild...

[jelboy89]

Just put a braided hose on my clutch with new cylinder. Couldn't get fluid to bottom. Found if you open the bleed nipple and pump away until fluid comes out then bleed as normal all will be fine