Brakes locked up, then failed...ideas?
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1976 1000 (Current Project)
1975 1000 Donor
1969 Cooper (Future Project)
1971 Opel GT
1972 Corvette Stingray
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Are you in Penticton? I live in Lake Country(Winfield). I have a few of these hanging about that you may be able to salvage parts from.
Ron
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Your part looks a bit heavier/thicker than the original. As long as you got the length right you should be OK.
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After a few hours with some 3 mil steel, drilling and filing, I ended up with the part in the attached pic. All back together and bench bled without an issue. I may end up ordering a new MC to have on hand, but this will should keep me on the road for a bit.
Without knowing the required metals specification, is this a gamble? Of course , one could argue that the original was not so corrosion-resistant or strong either. I admire your shadetree mechanic fix ( because I have been guilty of similar events) , but brakes are, well, life-saving.
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After a few hours with some 3 mil steel, drilling and filing, I ended up with the part in the attached pic. All back together and bench bled without an issue. I may end up ordering a new MC to have on hand, but this will should keep me on the road for a bit.
1976 1000 (Current Project)
1975 1000 Donor
1969 Cooper (Future Project)
1971 Opel GT
1972 Corvette Stingray
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You can order the conversion kit if you do not have a brake line flaring tool. Your 1976 Mini project is the car in question? The new master will have a fliuid level light with the built in float. You do not have to attach anything to it .Left hand drive conversion pipes are Mini Spares number BAU5655MS
Deb
Cheers,
Corey
1976 1000 (Current Project)
1975 1000 Donor
1969 Cooper (Future Project)
1971 Opel GT
1972 Corvette Stingray
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You can order the conversion kit if you do not have a brake line flaring tool. Your 1976 Mini project is the car in question? The new master will have a fliuid level light with the built in float. You do not have to attach anything to it .Left hand drive conversion pipes are Mini Spares number BAU5655MS
Deb
Keith & Deb
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As shown in the picture, the piece that joins the two pistons together corroded through and broke. So no return on the front circuit. If anyone has this piece and is willing to part with it, great. Otherwise, there is an NOS one on Ebay right now for the princely sum of $325 Cdn. Or, I just go with the GMC227 as a replacement, which may be a better option.
Current system is LHD front/rear split with the switch in the PDWA valve. If I go with the GMC227, I assume I can run the existing brake warning wires to the MC, but do I need the pressure reducing valve and conversion kit for the fittings.
Off the road for a while.
1976 1000 (Current Project)
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If in doubt, flat out. Colin Mc Rae MBE 1968-2007.
Give a car more power and it goes faster on the straights,
make a car lighter and it's faster everywhere. Colin Chapman.
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I cannot tell you what to look for with PDWA failures except it's easy to mess up their spool centering during brake bleeding. Actual PDWA failures can be seen with things like fluid coming out of the switch.
I pulled all 4 drums to check the installations and all the shoes were oriented properly. I redid all the adjustments. The rears were fine, but the fronts seemed to require quite a bit of movement. After I re-adjusted the fronts I had a pedal again. I'm still not happy with the feel as there is a bit to much travel, but at least they are working. I'll still bleed everything to make sure there is no crap in the lines.
However, while I can see that too much space between the shoes and drums would require pumping before good contact is made, I don't know how this could lead to the total lock-up of the brakes. If anyone can explain this it would put my mind at ease.
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I like to use the GMC227 master cyl, I put those in everything, I like the dual line split so if something goes wrong with one half of the system, there is still some braking. We have been running these in the racecar since we started 8 years ago and with something in the neighbourhood of 10,000+ race miles.
We have a full split system, with the front and rears completely separate, and using 5/8" cylinders at the back. Up front are the Mini spares 4pot alloy calipers. My Vintage racer has this setup, as well as a Vintage racer I am currently building. I have also used this setup in a 67 Traveller with drum brakes up front and it works a treat.
I know it doesn't solve your mystery, but it is a real-world solution if you can't get to the bottom of it.
Sean Windrum
1996 MGF VVC
1970 1275 GT Racer
66 Austin Countryman
63 997 Cooper (Under Construction)
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Kelley
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Kelley
"If you can afford the car, you can afford the manual..."
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I'm not as interested in whether the installation is technically correct at this point, but rather whether or not the odd mix of parts could actually cause the lock-up and subsequent failure. Its seems odd to me that the pedal will pump up and hold pressure, then if I let the pedal up, it will immediately go right to the floor with zero resistance.
Anyway, this 76 Canadian import has shown to be an odd mix of 75-77 parts so I didn't think much of it at the time, but when doing the brake system with the GMC159 master cylinder on the front/rear system, I originally ordered the GWC1102 rear cylinders with the 3/4" bore. However, they would not fit the backing plates (pin holes on the wrong side) and when I measured the old ones, they had 11/16" bores. So I ordered some GMC1129 cylinders and they fit fine. 1129's were used on Canadian minis with the GMC 159 MC, but normally with front discs, as shown in the attached chart.
I'd expect some difference in the pedal feel and braking from the smaller bore cylinders, but not completely failure.
Any thoughts on whether this could be a contributing factor? To much pressure in the MC?
1976 1000 (Current Project)
1975 1000 Donor
1969 Cooper (Future Project)
1971 Opel GT
1972 Corvette Stingray
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Last post: Jan 13, 2022 Member since:Feb 7, 2006
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If in doubt, flat out. Colin Mc Rae MBE 1968-2007.
Give a car more power and it goes faster on the straights,
make a car lighter and it's faster everywhere. Colin Chapman.
Total posts: 44
Last post: Nov 28, 2018 Member since:Sep 26, 2016
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Corey
1976 1000 (Current Project)
1975 1000 Donor
1969 Cooper (Future Project)
1971 Opel GT
1972 Corvette Stingray
Found 28 Messages