Just got thru bleeding brakes for a DE and the pedal went straight to the floor! No leaks, no bubbles, just no pedal..period. Better to happen in the garage than at the track. Won't start work until MC arrives. Hope there's no leak into the booster. Good idea to bench bleed b4 installing? Any other tips? TIA!

 

Any updates on this ?

 

Just got the MC in this afternoon's delivery. Will install tomorrow and let you know. Intend to bench bleed as best I can.

 

Installed the MC this a.m. Messy job, tho. No way to avoid dripping brake fluid other than plenty of shop towels and denatured alcohol to neutralize. Thanks to a very thorough bench bleed, it only took about 8 oz. total to bleed all four calipers. Got a nice, hard, high pedal now. Rather than OEM at $321, found a CENTRIC MC on eBay for $130 with free shipping, made in Italy, excellent fit. CENTRIC makes caliper rebuild kits, too, which include the dust boots.

 

Hey NC also everyone,

I am seeking for some tips on the Master Cylinder install, hope you can advise.

Should have researched more when I started this whole thing, failed wheel bearing and seized T50 rotor retaining screw prompted me to replace the rear rotors and pads. I have not bleed the lines (will do it right away when the bleeder tool arrives). Now the break pedal goes to floor rather quickly when engine is running. It holds a bit pressure when I pump the pedal with running engine and got spongy feel with pressure when the engine is off. No signs of fluid leaks.

1) Can I get a second opinion on the diagnostics of a bad master cylinder?
2) The break pedal also have a hiss during depression, I am thinking to replace the booster as well at the same time, it is straight forward?
3) How did you do the bench bleed with the new master cylinder? Anything different than generalized tutorials found online?
4) Reading about the master cylinder, the circuit involves clutch slave and ABS, I hope not to bleed the clutch slave and drag the car to a shop (after all the troubles) with an air trapped ABS, any precautions and tips on simplifying the job would be greatly appreciated!

MINI dealer is a distance away, getting this done myself seems to be a better option at this point.

Thanks in advance!

-X

 

Do not assume that anything is wrong until you bleed the lines in order RR,LR, RF, LF.
If that brings your pedal back to normal, forget about the rest of it. I mean, why replace your MC until it fails? How many miles on the car? If you do replace it, bench bleeding requires a simple kit available at most autoparts stores. Using the adapters and hoses, you just bleed by adding fluid while stroking the piston until no bubbles appear. You put the MC in a vice to do this and can use a big Philips screwdriver as a piston driver. Unless you have the special tool or can make one, leave the slave cylinder alone. The piston in the slave cyl. must be fully compressed while bleeding. If you get air in it, you're in for trouble and a bunch of brake fluid to get it out! p.s.: I've yet to get air in the ABS.

 

NC, Thanks for the reply and tips. I bleed the lines yesterday, gravity bleed worked nicely and I got an organized garage while letting the brakes do their work.

I just put in tie rods, Mintex pads, new rotors on the back along with new set of wheel hubs just past weekends and first disappointed about losing brakes after all that work. Now bleeding/flush the brakes made a big difference and the car is fun to drive once again - smooth, strong and predictable.

My car got 200k miles from frequent long distance commutes. I only "hope" to work on the mini once per year, and while I am signed up to wrench on it, I do as much as I can, that is why I change things with very sensitive level of alert, and hope to gain predictable outlooks from this practise. This brake job officially concludes my 2011 maintenance! Cheers and thanks again!

 

I am wondering if I have a bad master cylinder. When I press on the brake pedal it is firm, but then slowly the pedal falls about a half inch?

 

Question: What kind of brake fluid have you been using in your car before you had to replace the master cylinder??

FYI, I have a few good used master cylinders that would have worked cheap.

 

I'm in the same boat. Mine is leaking out the back between the mc and the brake booster.
You can get new ones from rmeuropean for $67.00.

Fluid was Valvoline Synthetic Dot3&4