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 Posted: Jun 17, 2019 09:07AM
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CA
It's not high at all through USPS...lets talk....email in my profile

 

"Everybody should own a MINI at some point, or you are incomplete as a human being" - James May

"WET COOPER", Partsguy1 (Terry Snell of Penticton BC ) - Could you send the money for the unpaid parts and court fees.
Ordered so by a Judge

 

 

 

 Posted: Jun 17, 2019 03:14AM
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Quote:
Originally Posted by Spitz
You may well be right about the 3/4" for split.
I ma have fitted the wrong ones...as I have a single system.  Damn it
If not for shipping costs to Canada being high I'd offer you a set of new 5/8" that I got by mistake for my car.

 

 

 Posted: Jun 16, 2019 09:29PM
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CA
You may well be right about the 3/4" for split.
I ma have fitted the wrong ones...as I have a single system.  Damn it

 

"Everybody should own a MINI at some point, or you are incomplete as a human being" - James May

"WET COOPER", Partsguy1 (Terry Snell of Penticton BC ) - Could you send the money for the unpaid parts and court fees.
Ordered so by a Judge

 

 

 

 Posted: Jun 13, 2019 10:01AM
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Not sure if that would make a difference with pedal feel but you would have the opposite problem Rosebud had - less rear brake, but shouldn't a twin shoe car have the 5/8" rear cylinders? I thought the 3/4" was later cars with dual circuit? Considering how cheap they are why not change them?

 

 

 Posted: Jun 12, 2019 07:13PM
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CA

Somewhat related question.....and save starting a new thread.

Regarding rear cylinder bore size;

I have twin leading up front.... single line system.  I installed all new wheel cylinders with 3/4" in back.  I have a lot of pedal travel after everything is adjusted up and bled properly.

Will 5/8" in the rear help fix this?..... ie: smaller bore, less volume

 

"Everybody should own a MINI at some point, or you are incomplete as a human being" - James May

"WET COOPER", Partsguy1 (Terry Snell of Penticton BC ) - Could you send the money for the unpaid parts and court fees.
Ordered so by a Judge

 

 

 

 Posted: Jun 11, 2019 06:06PM
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It would have been better if I had done my home work first. I was assured the brakes were fine having recently been done. I just rebuilt everything as it was. Turns out nothing worked and a full back half redesign was in order. The fun part was all the SS hose had BSP ends. There was no hard pipe in the system all SS hose. The std MK1 bias valve was located between hand brake master and rear wheels. Who has hydraulic hand brake anyway? Even worse if it don't work. I need to send some one pictures only 1000 before and afters. Steve (CTR) 

 Posted: Jun 11, 2019 03:40PM
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Quote:
Originally Posted by CooperTune
I recently fought the worst battle with brakes ever…
That’s a lot of plumbing, Steve. I’ll bet that took some time sorting out. 

 

Michael, Santa Barbara, CA

. . . the sled, not the flower

      Poser MotorSports

 Posted: Jun 11, 2019 03:06PM
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I recently fought the worst battle with brakes ever. The rally car has a .700 single line master. From there it splits and the fronts are KAD four pot magnesium calipers with 7.9 vented disc. On from there we find a Wilwood knob bias valve followed by a Wilwood .625 hand brake master. From there it splits between the rears. These are a little hard to find .875 rear wheel cylinders. Mechanical linkage removed and access welded up. The knob bias valve reduces pressure by 52 percent. In the beginning the master and the calipers were the only parts correct for the system. I ask on some of the boards but no help. I found the HP Brake book very helpful. Once you have done all the math it's as clear as mud. I can now lock all four or just the rears. As soon as I can get brake lights working I'm going looking for some smooth dirt roads. She is very stout wheel spin in all gears under full throttle. Steve (CTR)

 Posted: Jun 11, 2019 02:09PM
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Quote:
Originally Posted by Dan Moffet

If you apply say 50 lbs of force to a cylinder with 1 sq. inch of area, you'd get 50 psi.
If you apply the same 50 lb force to a cylinder with 2 sq. in of area you get 25psi.
Oh rightit's about the pressure, not the volumeApplied physics at work. Got it!

 

Michael, Santa Barbara, CA

. . . the sled, not the flower

      Poser MotorSports

 Posted: Jun 11, 2019 04:21AM
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CA
Just a guess:

If you apply say 50 lbs of force to a cylinder with 1 sq. inch of area, you'd get 50 psi.
If you apply the same 50 lb force to a cylinder with 2 sq. in of area you get 25psi.

.

"Hang on a minute lads....I've got a great idea."

 Posted: Jun 10, 2019 08:27PM
 Edited:  Jun 10, 2019 08:30PM
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Some of you may recall, I chased a front/rear brake bias issue for years [link]. The rears would lock-up well before the fronts. Using dual master cylinders w/ a KAD bias bar wasn't enough to keep the rears from locking. So I installed a Tilton bias valve. Still not enough. I swapped out the 3/4" wheel cylinders for 5/8" cylinders and after much tinkering, got the front/rear bias where I wanted it. Fast-forward to last week when the brake pedal went to the floor while sitting at a red light. It happened several more times on the way home. I should mention that the entire brake system was replaced during a not-so-long-ago restoration.

About a year ago I noticed that a fine, black particulate material would gather at the bottom of the front master cylinder. I'd use an eyedropper to pull the black junk out and top off the fluid. I even flushed the entire system a couple of times, but the black crud would reappear. After the pedal went to the floor, it occurred to me that the black stuff was probably a deteriorating O-ring. Since a rebuild kit was half the price of a new master cylinder, I dumped the Girlings and popped for 2 new Welwood masters.

Well, the bias problem returned in a big way. I had the bias bar and the bias valve maxed. I had the rear brake cylinders backed off so far my hand brake barely worked. I combed YouTube for clues and found a video by Tilton that offhandedly mentioned, "Of course, on a dual system you'll want to install the largest bore cylinder on the rear circuit." Wait! What?

A call to Tilton's tech-ref confirmed; the larger bore cylinder goes on the rear circuit, the smaller on the front. I've always had it the other way around. It just seemed to make sense—biggest brakes, biggest cylinder. Once I swapped the cylinders and readjusted the bias bar, valve, and brake cylinders to a more neutral position, my front/rear bias is spot on. My hand-brake even works again. Who knew? 

 

Michael, Santa Barbara, CA

. . . the sled, not the flower

      Poser MotorSports