13 replies to this topic

[beardylondon]

Hi All,

 

My Mini failed the MOT on the rear brakes.  I have replaced the rear drums as they were very worn and also shoes and springs, I have discs on front which are fine.

 

Went to bleed them, plenty of new brake fluid, starting at the back furtherest away, locked up the adjusters on rears as I was advised, I just can't get the rear brakes to bleed with out air bubbles, I've done the car multiple times, just get loads of air through.  Can't see any leaks. The fronts seem fine, no air in fluid, it is just the rears.

 

Any things I should be looking for?

 

Thanks in advance.

 

 

[mk1leg]

a loose pipe connector or the master cylinder seals are worn

[cal844]

I'd now chase the air out from the master cylinder

[MatthewsDad]

How are you bleeding? Eezibleed or brake pedal?

[beardylondon]

Am using brake pedal.

 

How are you bleeding? Eezibleed or brake pedal?

[MatthewsDad]

Is there any chance you're sucking air back into the system through the seal between bleed nipple and tube during the up stroke of the pedal? Sometimes what appears to be an airtight seal is in fact allowing air to be sucked in. Try a smaller bore tube if there's a chance the current one doesn't create an airtight seal. Try and get the rear of the car raised a little too.

[Rorf]

Keep MC reservoir full to brim - nipple open, push slowly down, tighten nipple and slowly release brake pedal. Repeat cycle. Oh and use plastic pipe from nipple to glass jar

[GraemeC]

Invest in an eezibleed.  When you use it, open the bleed nipples before attaching the hose to the tyre.

Then once done, leave the pedal wedged down overnight with a length of wood.

[beardylondon]

Thanks for all the replies.

 

After close inspection there was a small leak from one of the wheel cylinders.  So have replaced both sides now.

 

I tried with an assistant yesterday and couldn't get a solid pedal.

 

Tried again today with an Eezibleed, I get a hard pedal, then as soon as I disconnect the pressure (only 19 psi) from the spare tyre the pedal goes much softer, but not completely.

 

I should try again with an assistant, but any thoughts?

[andyapanel]

Try jacking up the front of the car and jam the brake pedal down.

Leave it overnight.

I think the theory is any air in the system will eventually move to the reservoir.

Good luck with it-the Eezibleed usually does it first time for me, but its good to have a plan B.

[beardylondon]

OK I got it all bled and working fine, and it still failed the MOT just on the rear brake efficiency.

 

Someone said it could be the rear bias valve and to ditch it completely and bypass it with a T piece.

 

However just been reading this, anyone fitted an MS72?

 

https://www.calverst...ias-adjustment/

[cal844]

It could also be the rear brakes not adjusted properly

[beardylondon]

they are adjusted spot on by an experienced mechanic, as I was pulling my hair out, I got a second opinion and got it all adjusted correctly.

[beardylondon]

After speaking to a number of people I decided to swap MOT testing stations, went from one with a digital machine, to one with an older one with the big analogue gauges, and it passed!