So what you're trying to say is my wife isnt going to be much help? 

So I tackled this all this morning before wife and baby were up and think I got it figured it, for the most part.  ulled the wheels off, jacked the car up, and used a one man bleed kit I got at Advanced for 7 bucks.  The whole process was kind of a pain and time consuming but not difficult at all.  I think the MC rebuild was semi-successful, but will probably need replaced eventually.  After the bleed, I have much better brake pressure, but not what I would like.  This is the first drum all around car I've ever owned though, so maybe I'm just spoiled and looking for disc level stopping.

The clutch MC/slave cylinder was extremely easy and quick.  Thanks for your help guys, at least I can shift and stop the car now.  On to the next issue!  Screw on oil cannister conversion, radiator replacement, and interior carpet replaced are next on my list.

If your rebuild was successful, the MC works fine with S discs.

Bleeding is simple, you don't need fancy tools.

You need a helper who follows directions.  Keep in mind that if they let up on the pedal when the bleeder is open, air comes in.

Also, keep in mind that pumping wildly introduces bubbles into the fluid.  This is an activity best done slowly.

I use a simple bleeding cup, usually made by Lisle, available at nearly any auto parts store.  It is handy in that the inlet to the cup can be kept immersed in fluid, so that air cannont sneak back into the system.

Usually, on those old MCs, I file the flange of the plastic reservoir flat where it mates against the cast of the MC body, and file the spacers a bit to complement.  Hopefully yours does not leak at this joint.

I always start at the MC and crack the line loose enough to allow a smidge of fluid to come out as the pedal is depressed, and I close it before the helper lets up on the pedal.  This helps to start things.

The bleeder cup, on the LH front hub to start, should first be used simply as a collection vessel.  If you have bled at the MC, you should be able to get some fluid movement, and once a bit is in the cup you can leave the bleeder cracked open ever so slightly and do easy slow pumps to get fluid moving.

Emotionally prepare yourself to go around the car a couple of times.  Adjust the adjusters tight to the drums.  Have lots of fluid on hand, don't let the MC run out or the cup overflow.

Same for the clutch.  The slave has a bleeder, but start at the MC and move out to the bleeder 2nd.

Ok, so did a rebuild on the MC today.  What a pain in the A$$.  You essentially have to remove the clutch MC to get to the nuts on the brake MC on the bulkhead.  So I detached both clutch and brake MC, rebuilt the the brake MC, and reattached everything.  The Florida heat and humidity wasnt helping things, either.

So now my brake and clutch pedals go straight to the floor with no pressure.  I'm assuming because I disconnected the lines into the MC's, air has been introduced into the systems and I need to bleed both now, correct?

If so, are those one man bleeding kits worth a damn? Or should I talk my wife into pushing on the pedal for me while I back on and off the breather nipples?  Anything Mini specific I need to know about the brake bleeding process?

What about the clutch system?  Does it bleed from the slave cylinder?  And the system operates off of DOT4 as well, correct?  Sorry for the novice questions, just want to get this stuff sorted.

I'm starting to think just that... I adjusted the brakes, no luck.  MC rebuild kit should be here this week, we will see if that works.  If not, I may just break down and buy a new disc set up.  That would also be the safest thing to do.  This is my third mini but first that has drums up front and I'm a little concerned about its ability to stop in a hurry when I need to, in a hurry.

If I were to buy a new S disc set up, the one our host and others have that claim to have everything, is that really everything that needs to be swapped out?  You mentioned new lines, etc, which is probably a good thing to replace while you're digging deeper.  Will the BMC159 Brake MC work with a disc set up or should I also upgrade to the newer yellow band MC?

Thanks so much for the help fellas.

First, this is important; I don't even bother with drum brakes on a mini anymore, and I have been messing about with them for 30 years.  A set of S discs will cost less than the purchase of necessary parts and the work involved in maintaining them for about a year.

 

Having said that, buy all new wheel cylinders, backing plates if necessary to replace worn or damaged or seized adjusters, new flex lines and either a new or rebuilt master cylinder, and your problem MAY go away.  The problem still could be the brake lamps switch or pressure imbalance switch or something else I haven't considered herein.

VV yes that is what i mean by bleeds down. Adjust all the brakes before you decide to change it, bleed the system from the farthest point away from the master cylinder first. Also if there is air in the system i have found it easier to get the air out if the back is raised as high as possible.

Seems like an obvious question, but I honestly havent checked.  I just started with what the seller told me.  Its on my list of things to check before I drive it farther than 2 miles to work.  I will pull the front wheels off and check the adjusters.  Rear brakes/parking brake working as expected.  Drums all around.

I will check this in the morning.  By "bleeds down" do you mean I pump it twice, have break pressure and while holding my foot on the pedal, it slowly goes down, losing pressure?  Will have to verify in the morning, but fairly certain this is the case.  Will report back.

Are your  brakes set correctly??

Drums front and rear?   Un-adjusted brakes can result in having to pump once or twice

If someone has fitted discs to the front....still important to have rear brakes set periodically

No not unless it "bleeds down" after you have pumped it 2 or 3 times with your foot on the pedal and the car stopped. Read my previous reply.

Ok, car is here and Ive had the chance to drive it to work once, run out of gas once, and push it up hill a half a block.  Fuel sender unit needs to be replaced as well!

Anyway, heres a few pictures of the brake master cylinder.  Overall the car is running very well and pretty solid but the brakes need some work.  I was told by the seller that it needs to be rebuilt.  You tell me...  The brakes work well but require 2 or 3 pumps to have full braking power.  Brakes dont really function on the first pump and get pregressively better with another pump or two.  Brake master cylinder the culprit, in your all's opinion?

And just to be certain, heres a few pictures of the MC.  GMC159?  Thats what it looks like in my haynes manual.  #2 type, according to Haynes?

//www.flickr.com/photos/ryanlikesvespas/7606610594/in/photostream#

//www.flickr.com/photos/ryanlikesvespas/7606610934/in/photostream/

 

Also, the last 1275 engine sprite/midgets had an internally identical master cylinder that used a reservoir that allowed it to be fitted horizontally.

The GMC159 is worth having it sleeved and rebuilt. They can be found new but they can also be pretty expensive. It's a good master cylinder and I really like the large diameter reservoir.

Just in case you decide you want to hunt down a NOS master cylinder the original Lockheed part number is 4222-427 which became LM12427 when Lockheed changed the numbering system. GMC159 is the Unipart part number. The Lockheed rebuild kit SSB927 later became LK10927. This master cylinder was used in the Austin America, some Innocenti models and was available as part of a Special Tuning kit.

Kelley

Dismantling these MCs can be a bit tricky, and sometimes a rebuild of what appears to be a rebuildable unit doesn't seem to work out, however I would sure try to rebuild it before I went to any other style of MC.  Keep this thread posted when you get a closer look at the car.

It could be as simple as a worn clevis pin and oval shaped pushrod!

If you do need a new master (I believe it is GMC159) and I don't know where you'll be able to find a new one. You may have to rebuild or convert to a later master, unless someone knows of a source.

thanks guys, you're right. ill hold off and wait.

i would rather buy new, if i need to go down that route. ill chime in when the car gets here.

If it stops with two pumps i will bet the master is good unless it bleeds down. If it has drums all round they either have air in the system or are not adjusted correctly. I too would wait until it gets to you just because the PO may or may not have replaced everything else does not mean it has to be the master cylinder and if it is i would buy new myself.

Personally I wouldn't go spending the money on any parts until you have a good look at it yourself. If you haven't seen the car yet, don't trust the seller too much. It may not be the master cyl, and you would have wasted money. Check it out when you get it and determine from there what it actually needs. The sellers intentions may be good, but he could also be wrong too! Good luck...

So I just purchased another Mini and its being picked up in Denver tonight and will arrive in Pensacola in a couple days. Its kind of a "project" but overall, appears to be a solid car. Anyway, the one issue it has is the brake master cylinder needs to either be rebuilt or replaced. I've looked on both our host and other websites and went back and forth on rebuilding or replacing.

Could anyone help me out with a link or info on a full blown replacement? Its a Canadian model Mini. 1973. If you are going to need more info and pictures of what the current one looks like, I'll have to wait till the car gets here to get one. Figured I could get a jump on it, order either the rebuild kit or a replacement and have it here waiting for the car. Sounds like its a two pump stop right now and all the other brake components have been sorted and the seller claims its the brake master cylinder.

Ive been told this is the appropriate rebuild kit for canadian and inno minis. //www.minimania.com/web/item/LSSB927/InvDetail.cfm

Help/comments? Thanks guys. I'm sure I will have questions once this car gets here.