8 replies to this topic

[Lyle425]

Can anyone offer some advise for bleeding a new master cylinder?

I have had advise to fill the fluid up, crack off the the main outlet pipes and pump the pedal until it comes out if the outlets ports, and then re connect and bleed as normal.

I also have an eezibleed kit which should help.

Does anyone else have any advise when doing this?

My initial problem was that I couldnt get any fluid from any bleed screws, and after disconnecting main brake pipes from the old master cylinder I couldn’t get any fluid out of that either- so a new one is being fitted.

Thanks

Edited by Lyle425, 17 June 2020 - 06:27 PM.

[cal844]

Dont use an eezibleed, minis dont like them.

As always when using brake fluid dont let it get on paint(paint will peel) or your hands(it burns).


To bleed the master cylinder disconnect the pipes and get an assistant to pump the pedal (make sure the ports are covered whilst pumping the pedal).

You'll need to chase the air out the lines so you have 2 options. As above an assistant makes life easier.

Option 1 is to chase the air along the line front to rear by loosening each union, pump the pedal a few times until fluid comes out the union then tighten, repeat along each line. Keep the pedal fully pressed while you close the nipple.


Option 2 is to leave the nipples open and pump the pedal a few times, I usually work in 10 pump cycles... so open the nipple, pump the pedal until fluid comes out, then keep the pedal fully down to close the nipple.

Bleed order is Nearside rear being the furthest from the MC.

Nsr
Osr
NSF
Osf.

Hope this helps

Cal

Edited by cal844, 17 June 2020 - 06:37 PM.

[Lyle425]

Dont use an eezibleed, minis dont like them.

You'll need to chase the air out the lines so you have 2 options. An assistant makes the following alot easier.

Option 1 is to chase the air along the line front to rear by loosening each union, pump the pedal a few times until fluid comes out the union then tighten, repeat along each line. Keep the pedal fully pressed while you close the nipple.


Option 2 is to leave the nipples open and pump the pedal a few times, I usually work in 10 pump cycles... so open the nipple, pump the pedal until fluid comes out, then keep the pedal fully down to close the nipple.

Bleed order is Nearside rear being the furthest from the MC.

Nsr
Osr
NSF
Osf.

Hope this helps

Cal

Why don’t Minis like eezibleeds? It’s braking system is no different to that of any another car of the era.

Edited by Lyle425, 17 June 2020 - 06:36 PM.

[cal844]

Dont use an eezibleed, minis dont like them.

You'll need to chase the air out the lines so you have 2 options. An assistant makes the following alot easier.

Option 1 is to chase the air along the line front to rear by loosening each union, pump the pedal a few times until fluid comes out the union then tighten, repeat along each line. Keep the pedal fully pressed while you close the nipple.


Option 2 is to leave the nipples open and pump the pedal a few times, I usually work in 10 pump cycles... so open the nipple, pump the pedal until fluid comes out, then keep the pedal fully down to close the nipple.

Bleed order is Nearside rear being the furthest from the MC.

Nsr
Osr
NSF
Osf.

Hope this helps

Cal

Why don’t Minis like eezibleeds? It’s braking system is no different to that of any another car of the era.

The valve on the bulkhead closes off the relevant circuit if it senses a vacuum.

[Spider]

I've been using a Gunsons Ezibleeder for a long time. I find they work OK to get fluid through the system, but to get all the air out, once fluid starts coming out of some of the wheel cylinders / calipers, I go over to the old skool method of pumping the pedal.

 

Sometimes new cylinders can be difficult to start to get fluid through them, this is I'm sure, in part from the rubber grease that's used in assembly blocking or part blocking the very small ports between the cylinder and the reservoir and this I find is where the Ezibleed is handy as rather than let gravity try to feed to fluid in, it's fed by pressure , thus dislodging the assembly grease in them.

[Tremelune]

You're on the right track. If there's air in the master cylinder, it may never come out without bench bleeding:

 

 

Ideally, you want to do it in a vice with a tube/plug kit (10£), though I did mine while installed on the car. I cut an old/extra brake line I had (M10-1.0), and attached a clear tube to the cut brake pipe. I disconnected one line from the master and installed my thing there and pushed the brake pedal down with a long wrench by hand. Once I stopped seeing bubbles, I repeated the steps on the second line in the master. Then I bled the calipers as per usual.

[Lyle425]

I bleed with the same advise Mini Moke have. The eezibleed kit made life much easier and it does work. Finishing off with a manual pump of the pedal. It takes time but you can get the right results.

[g0myw]

when I rebulit the MC this winter I did the 'on-bench' getting fluid in trick.
Then used the ezibleed. [I've always been a mytivac guy before]
Took a couple of goes all round [all brakes had been restored]
As suggested a few pumps on the pedal helps.
It'll eventually come all good.

[Steve220]

I let them gravity bleed for an hour if brand new. Then go to the 2man bleeding method and sequence above. Works every time ??