Still having trouble bleeding brakes!
Turbo Mini Forums

I recently bought a tandem master cylinder (yellow band type) from ebay, which I rebuilt with new seals and secondary piston etc.

I have bled the master cylinder on the car and then proceeded to bleed each wheel.

I wasnt sure on the order to bleed them as was unsure on the type of system I have, front to rear split or diagonal split dual circuit system. The car is 1990 and was told that it would be front to rear so bled the passanger rear to drivers side rear, then passenger front followed by drivers front.

We did that a few times but only the drivers side rear locks up. The others lock up after the pedal is pumped several times.

I replaced the passenger side rear cylinder as thought it was leaking but that didnt have an effect either!

I know its most likely air in the system somewhere but we've bled it all endlessly with no luck!! I just wanted to make sure I was bleeding in the right order?

Please help me obi-wan youre my only hope

Rich

try doing the rears first then the fronts.

no longer a series, but still 1.3 turbo.

Thats the way I have been doing it mate!

p/r - d/r - p/f - d/f is the way ive been doing it?! Clear bubble-less fluid flowing freely out of each wheel :s

Rich

Clamp off each flexi hose in turn to see if the pedal improves. Have you fitted new linings at all to rear and are they adjusted properly?

I suspect the master cylinder is your problem - they rarely like being rebuilt ( sometimes you can be lucky !)

On 5th Sep, 2011 Vegard said:
I stand corrected. You should know

Don't you have to take the pressure differential switch out to bleed that type

Metro turbo weekend driver,Mini turbo in the making again!

NEVER bother rebuilding master cylinders. Buy new ones, every time.

Have you got the right size rear cylinders .500"/.625"/.750" to suit the front.
Are you sure the one that is locking hasn't got contaminated linings(had it before.lining kept rolling into balls instead of dust)

and have you got the rear brakes connected to the bottom of the master(incase it has a larger piston((can't remember))

Edited by Dangerous on 19th Aug, 2007.

Metro turbo weekend driver,Mini turbo in the making again!

Didnt realise you could get different sized rear cylinders! What effect would it have if they werent the right ones for the calipers? The rear cylinder i replaced was a new (spare) one I had fitted to my previous mini and have converted the calipers over from that car to this car so in theory should all be ok as that combo worked fine before!

I have also checked the shoes on each side if theyve been contaminated and absorbed any fluid but they are fine aswell!

EDIT: The top union on the master cylinder goes to the left hand side of the pressure regulating valve and the bottom to the right hand side, thats right yeah?

Rich

Edited by richminiturbo. on 19th Aug, 2007.

If you have a servo as well you need to pressure bleed the system either using an ezi bleed or with the engine running to eliminate problems with either the Mcyl or servo. Don't kid yourself it cannot be those components we all make mistakes ( i spent two days trying to work out why my spare engine would not start having convinced myself everything was fine - the timing disc was not where I thought I had aligned it as i copied where it was on the other engine to find what I thought on the other engine was tdc was just a white mark of paint).

All problems are usually simple ones - if the rear brakes are correctly adjusted and the shoes (linings) not contaminated a spongy pedal that pumps up either has air in it you say there are no bubbles in the fluid - so either you are mistaken and there is or the master cylinder/and or servo are f*cked. If the system has a loose union drawing in air it should leak as well making it fairly obvious.

On 5th Sep, 2011 Vegard said:
I stand corrected. You should know

Trust me, I've not gone mad .... try this.

Pump the pedal a few times, and get somebody to hold it down for you whilst you crack each nipple then immediately tighten them again.

Work round the car in order. Basically what this is doing is telling you that each of the bleed nipples is operational and sealling as it should.

Now check that there is no weeps around the seals on both slaves and calipers.

Find something to hold down the pedal, put it in place, loosen the cap and forget about the car over night ..... I find a few beers helps with this!!!!

Pressure bleeding can help but personally the only thing I have ever been able to do successfully with an Eazi Bleed is remove paint!!!! LOL

What this does is open the whole system and the air will find it's way out given time.

If you still ahve problems replace the pressure balance valve with two lengths of pipe and try again. If that works replace the valve.

If not I'll have to go away and think a bit more.

Every day is a school day ...........

How fast and how expensive ...... the same question...

Roger is right but I seem to remember now what happens with a remote servo - air gets trapped in one of the link pipes and unless you pressure bleed it with an ezi bleed or have the engine running even his method might not work - it is a right b*stard from memory.

On 5th Sep, 2011 Vegard said:
I stand corrected. You should know

i agree with the chocking of the pedal over night. i spent all day once bleeding the brakes with no luck and no air coming out. chocked the pedal down hard over night and had a perfect pedal the next day.

scruffy he doesnt have the servo in this car - he has converted to non servo afaik so chock the pedal rich and see how it goes

chocking the pedal works on all types of brakes and the clutch.

Rich, are you still using the sh*t brake equalizer valve bolted to the bulkhead?

They can be an absolute nightmare!

and also are you trying to lock the brakes with the wheels off the ground or driving?

Are you using new DOT4 brake fluid?

Old brake fluid will absorb air and water (i think) and will never give a firm pedal.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

Pumped the pedal until it felt harder last night and wedged a jack bar onto the pedal and seat after taking the cap off of course!

The brakes have been locked up all day, im still leaving the bar a little longer will test the brakes a bit later on!

Leaving it with the pedal depressed hasnt helpled!! Theres been no leeks while its been under pressure either! hmmm

Nah i dont have a servo scruffy, i converted from a servo to the yellow band type master cylinder!

I got two pipes made up at my local motor factors and they arent leaking at the unions or anything, what do you mean by going up slightly?

The thing that makes me think its not the master cylinder is that i was having the exact same problem when trying to bleed the system with a servo, i thought it might be the master cyl on the servo so ditched it and got the yellow band type one, only to discover im having the same bleeding trouble!!

The brake compensator couldnt be to blame could it? Im getting fluid to either end of the car obviously and so that indicates its not blocked or anythingm could there be an air lock inside of this?

Rich

the other day i change front and rear pads on a car and had no pedal! are the rears adjusted right up tight? have you fitted new pads?

Yep I have fitted new pads! And have checked that the adjustment is right on the rear drums!

What problems could changing the pads cause?

Rich

Can you confirm that you have adjusted the rear brakes so that they bind ever so slightly?

Edited by Paul S on 21st Aug, 2007.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

new pads sit on the old worn disc but not quite square. when you lift your foot off the pedal the pad springs back pushing the fluid back to the master cylinder.

if you have bled the system and dont get any air, and you have chocked the pedal then it may not be air.

wind up the rear adjusters up tight then back off so you can only just turn the wheels by hand. then drive the car (on private road) and use the brakes to bed them in

then check the difference in pedal feel.

dont drive to much as the heat produced by binding brakes can reck discs and also produce brake fade.