BTW, there a technical article on installing the GMC227 MC in the articles section of this site.  If you need the valve, I have one.

Does anyone know if a GMC 227 MC can be used without a pressure reducing valve (the kind that is separate from the master cylinder)?  My car does not have one.

My 1976 Cdn Mini is a front/rear split with a 159 MC, for what its worth.  The listing attached may help.

Cheleker:  Absolutely sure.  One line from the MC goes to the front brakes, the other to the rear.    

GMC167 is diagonal split. Are you sure that diagonal isn't what you're 1979 Canadian car has?

We need some help from the many Canadian Mini owners that post on this forum!

Thanks to both OKMini and Croc7 for your helpful replies.  I now agree that I don't have a GMC 159.  It's probably a GMC 168.  Croc7:  no, I didn't bench bleed it, but pressure bled it and pedal bled it multiple times, and the pedal never builds up any pressure.  I was tempted to send it out to be sleeved & rebuilt, but I can buy a new GMC 227 for about the same money.  I'm still confused about two things:

1)  The GMC 227 has a stepped bore and mine does not.

2)  Minimania's description of the GMC167 at:  www.minimania.com/part/gmc167/Classic-Austin-Mini-Brake-Master-Cylinder-Dual-Late-For-Canada-Models  says that it's for front/rear split systems.

I'll probably go with the 227,but I still feel like I don't have ground truth yet.

No experience with a GMC167 MC but I know a little about the GMC159.   Did you bench bleed the MC before installation?  Also, with either the front/rear split or diagonal split system, the info that I have says to bleed both front and both rear brake cyl at the same time.  I found it unnecessary with my front/rear split MC.  I just bled the brakes using the usual method starting with the wheel farthest from the MC.  If you want a GMC159 MC, front/rear split with the large round cap, I have one available.  My email address is in my profile.  For what its worth, Mini Spares description for a GMC167 MC says its for a diagonal split system.

Information I have found is that the GMC159 MC has the round reservoir, and that the Canadian Minis from 1976-1980 with a front/rear split and square reservoir is a GMC168, also NLA, but suitable replacement is GMC227 which also requires a conversion kit.

There is information on the Somerford Mini site detailing some of this.

 

I have what I understand to be a 1979 mini 1000, Canadian market car.  I am trying to rebuild the brake system, and have encountered a conundrum with the master cylinder.  It is a dual circuit, front/rear master cylinder with rectangular reservoir, 0.700 inch bore (not a stepped bore), with the pressure differential piston and the pressure switch.  I need to replace it, because I rebuilt it with all new seals (after cleaning up the bores as best I could), and it does not bleed out or build any pressure.  I want to replace it.  I believe it to be a GMC 159, which is NLA.  From everything I have read, it appears that a GMC 167 would be the best replacement.  However, I have encountered conflicting information about the GMC 167 being for front/rear vs diagonal split systems.  Does anyone have any experience/insight with Canadian market cars and/or the GMC 167 master cylinder?