26 replies to this topic

[Spider]

Plenty of sleuthing suggestions already.

If it's the servo then it should effect all 4 brakes, but could be less noticeable on the back. Also consider seized caliper pistons, though it's less likely both sides would be stuck on equally.

The discs and pads would need to heat and expand through friction so would need a bit of driving to bind, whereas a hydraulic fault would happen as soon as you used the brakes and the servo would kick in as soon as the engine starts.

 

Perhaps cracking a bleed nipple here when the brakes lock on would shed some light.

[Thelowrider]

OP have you had any luck with this?

[MinesRed]

OP have you had any luck with this?

Hav'nt yet,no...been told to disconnect the vac hose from the manifold to the servo to see if the one way valve has failed.
Can't turn engine on at moment because of other work in progress but she's sitting there now with completely free brakes.
Got to be something sticking somewhere.

[MinesRed]

Hello all.
Been out at the Mini today and I have a question regarding the brake servo..
If the vac hose and linkages are all disconnected should I be able to move the servo pushrod by hand?
This is with the engine switched off,I noticed the mechanism sticking so investigated and this was when i noticed but am not sure if you could move it freely by hand.
Thanks all

[Thelowrider]

OP have you had any luck with this?

Hav'nt yet,no...been told to disconnect the vac hose from the manifold to the servo to see if the one way valve has failed.
Can't turn engine on at moment because of other work in progress but she's sitting there now with completely free brakes.
Got to be something sticking somewhere.

Just take the one way valve off and try and blow through it, obviously you will only be able to blow through one way.

I still wonder if there is an issue with master cylinder for it to only affect the front brakes if it was the linkage etc it would affect all the brakes same goes for the servo.

I’d just pull the master cylinder off the servo and make sure there’s no corrosion.

[MinesRed]

Evening all.
Took the Mini out today and after around 15 mins the brakes stuck on.Limped home and left the car in the garage.
Went out later on and the brakes were free.
Took the master cylinder off the servo to check for any obstruction and noticed with the master cylinder loose the brakes were completely free but when the master cylinder was tightened up fully against the servo the brakes were binding.
I've made a temporary spacer to see if this cures the problem,but i've just thought I could adjust the servo linkage back around 5mm,I think there's adjustment left on it.
It seems as if the master cylinder/servo side is at fault,I read somewhere about spacers being fitted here,are they still available,if this is the area I read about.
Thanks again folks.

[Ethel]

Could be, does the pedal and its linkage move freely with the master off?

[MinesRed]

Could be, does the pedal and its linkage move freely with the master off?

Yeah,everything moves freely but the pedal doesn't return without a little help,fine with master cylinder on tho and feels more like a brake pedal..

[nicklouse]

disconnect the pedal assy from the MC and check that the pedal moves freely. if not give the bushes in it a lube. if yes then you have issues in the MC.

[McBrush]

Hi! New to here and this is my first post.
I have a 2001 Mpl
While driving last week my front brakes started to bind and heat up.
I have replaced the master cylinder, front flexi hoses, brake pads and this evening the proportion valve, with still no success.
The Calipers are working as they should and I removed the vacuum pipe from the servo.
Did loosing the servo rod cure your problem or did you try the spacer?
Thanks!

[MinesRed]

Hi! New to here and this is my first post.
I have a 2001 Mpl
While driving last week my front brakes started to bind and heat up.
I have replaced the master cylinder, front flexi hoses, brake pads and this evening the proportion valve, with still no success.
The Calipers are working as they should and I removed the vacuum pipe from the servo.
Did loosing the servo rod cure your problem or did you try the spacer?
Thanks!

It turns out that the servo seems to be at fault,it is sticking internally,although not as bad now it is lubed up.
Also if I bolt the master cylinder tight against the servo this makes the brakes bind enough to eventually lock on.
I have made a temporary spacer at 5mm to eliminate this but I am soon going to replaced the servo with a new one.
The servo could be your issue?

Edited by MinesRed, 04 August 2018 - 09:40 PM.

[McBrush]

Thanks for your advice. I installed a 2nd hand servo and this has cured the problem.
I am going to invest in a new one and put the original master cylinder back on.