bmwe21.net forums

The 323 had porridge for fluid, seized pistons in the front, and stuck sliders at the rear.

Rebuilt both fronts with new pistons and seals, freed up and copperslipped rears, flushed out fluid from system.

The brakes worked, but pedal had, almost a 2 step operation....and would go to the floor sometimes, albeit it with some resistance.

Suspecting the rather ratty looking vacuum hose, this was replaced, along with the valve.

Brakes bled again....nice clean fluid, no air.

Pedal as before. Curiosity led me to loosen and remove the drain plug on the MC....now I have nothing...pedal straight to the floor with no resistance.

I have removed the reservoir, the pipes, forced fluid through the MC. Replaced pipes, reservoir, re-bled...still nothing at all.

Do I need a new MC ? or am I missing something ?

Is it worth rebuilding the MC, or just replace ?

Thanks in advance K

If the bores of the MS are corroded stick it in the bin and replace it. Not worth taking risks with brakes as they come in useful.

my master cyl was dodgy on mine a couple of years ago. if you pressed the pedal slowly it would go to the floor, but if you stamped on it it felt normal.

good second hand one was fitted its been fine ever since.

old fluid has moisture in it and corrodes the brake components internally.

Can i take it that it is most likely the MC causing the problem ?

Would make sense, the fluid was black, so would have been holding plenty of mositure...car has been used little in the last 10yrs or so, I suspect the MC has been put to more work during my bleeding attempts.

Best place for a replacement ?

Brake parts International have them listed, but the image shows a LHD one...

Really would like to get it sorted soon, spent half on Friday on my back POR 15 ing the rear underside and fitting the new pre-silencer and back boxes.

Need a nice drive in her to make it feel all worth while.....


K

a drive or not, trust me all work you put in is worth while! lhd m/c will be the same wont it? just mounted differently with the supid extended linkage down the o/s innerwing for rhd? i cant imagine they would cast different m/c aswell?

Brake pipes exit on the opposite side, meaning the pipe work would need extending and I doubt there is room TBH.

Stripped down the MC this morning, and apart from gunge and crusty crap it seems OK, bore is clean and seals look OK.

So cleaned her up, and reinstalled...still have no brakes.

I can move air and fluid through the rears, but although fluid will drip via gravity through the fronts, the MC pushes little or nothing to the calipers.

Though undoing the unions at the MC and I get jets of fluid from the front outlets.....very odd!! an air lock perhaps ? Or maybe just not moving enough

But why both...? they are seperate lines! arrghhh!¬ getting frustrated now

Only thing I am unsure of, is where the locating pin/bolt is supposed to be positioned against the internals.

No 5 on this schematic

https://lh5.googleusercontent.com/-5fVh ... iagram.jpg

Do I depress the plunger and screw down, or leave uncompressed...both parts of the internals have possible careas for it locate.

front flexible hoses collapsed inside?

murran wrote:front flexible hoses collapsed inside?

Checked those, seem OK.

Stripped the MC again...one of the secondary piston seals looked a little flat on one side when inspected more closely.

So I swapped tht seal with one from the primary, and got the reverse symptons...fluid at front, none at rear.

Looking likes it definately the MC then......

Wheres the best place to get a new one...I can;t find any UK listed ATE suppliers in the UK on the web...

Part No is ATE 03.2120-0562.3 if anyone can help.

Cheers K

Brakes international will sort you out...

http://www.brakesint.co.uk/

drjim wrote:Brakes international will sort you out...

http://www.brakesint.co.uk/

Cheers, been on there..got my front caliper pistons and service kit from them, quick service as well.

Pic of MC looks like a LHD one though, can I assume its just a generic pic ?

K

you can never be sure unless you ring them.

Murran speaks the truth, give them a ring and ask, they will sort it. I had a problem with calipers on my old blue car, the boxes were right but I had two nearside calipers, one phone call got a replacement on the way, I dropped the wrong one back to them a week later with the core refund calipers. Good service and knowledgable chaps.

ordered my 323i discs off them ages ago. two days later i got them. good service.