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9/14/2018 9:37 AM  #1


Master Cylinder Advice

I will be converting a 1966 4 wheel manual drum car to 2014 GT front and Explorer Rear (8.8) disk brakes.  I have been reading a ton on this and decided to try the PB 6.2 master that Steve sells.  Recently, I found this:

https://wilwood.com/mastercylinders/MasterCylinderProd?itemno=261-14158-P

Price aside, what are everyone’s thoughts on using this MC?  I have aspirations to track the car, but likely it will spend most of the time on the street.  What can I expect from a pedal feel perspective?  Is going to power boosted brakes the best route?  I like the idea of buying a manual master with the ability to add a booster later if desired.  I also like Steve’s boosted setup with the new pedals, but would need one with a stock clutch pedal as I plan to keep the Z-Bar.

Any and all comments appreciated.

 

9/14/2018 3:19 PM  #2


Re: Master Cylinder Advice

I have 4-wheel discs and am using a 94/95 Cobra SVT MC (Baer recommended), 15/16" bore, Raybestos # MC390217 w/o a booster.  Brakes work fine, but pedal pressure is an issue, you better have a strong right leg for an emergency stop.
I am currently planning to install a hydroboost system (Winter project).


65 Fastback, 351W, 5-speed, 4 wheel discs, 9" rear,  R&C Front End.
 

9/14/2018 3:34 PM  #3


Re: Master Cylinder Advice

Master cylinders are designed to work with power assist or without; the bore sizing is specific to the application.  Mix and match won't work well.  Race cars usually use manual brakes because they don't make enough vacuum to operate power brakes.  Race cars are also light and easier to stop.  Often they use twin masters with one for each circuit (front and rear) with a balance bar to set bias or an in car adjustable proportioning valve on a single master.  None of that stuff is a great idea for the street though.  For moderate track use good brakes will be fine, and much cheaper than all the stuff required to make a race setup work. 

The 15/16 bore Cobra master cylinders are meant to be used with a power booster.  I would use a different master in an unassisted application.  People have found that even swapping this master in front of a stock GT booster in a Fox yields less than optimum assist when swapping to 4 wheel disc.  The '93 Cobra booster is the preferred choice for that application.  The '93 Cobra master is the same as the '94-'95, except that the lines exit on the inboard side instead of the outboard side. 

You will also need an adjustable proportioning valve in the rear brake line to properly set the bias. 

There are boosters that work with the stock Z-bar; I remember reading a thread on here not too long ago about that.  These cars had manual transmissions with power brakes from the factory depending on options, so it absolutely can work. 

 

9/15/2018 9:20 AM  #4


Re: Master Cylinder Advice

TKOPerformance wrote:

Master cylinders are designed to work with power assist or without; the bore sizing is specific to the application.  Mix and match won't work well.  Race cars usually use manual brakes because they don't make enough vacuum to operate power brakes.  Race cars are also light and easier to stop.  Often they use twin masters with one for each circuit (front and rear) with a balance bar to set bias or an in car adjustable proportioning valve on a single master.  None of that stuff is a great idea for the street though.  For moderate track use good brakes will be fine, and much cheaper than all the stuff required to make a race setup work. 

The 15/16 bore Cobra master cylinders are meant to be used with a power booster.  I would use a different master in an unassisted application.  People have found that even swapping this master in front of a stock GT booster in a Fox yields less than optimum assist when swapping to 4 wheel disc.  The '93 Cobra booster is the preferred choice for that application.  The '93 Cobra master is the same as the '94-'95, except that the lines exit on the inboard side instead of the outboard side. 

You will also need an adjustable proportioning valve in the rear brake line to properly set the bias. 

There are boosters that work with the stock Z-bar; I remember reading a thread on here not too long ago about that.  These cars had manual transmissions with power brakes from the factory depending on options, so it absolutely can work. 

TKO - regarding the differences between the 93 and 94/95 Cobra MCs was that the 93 also has a 1" bore as opposed to the 94/95's 15/16" bore.  I don't think this difference impacts the need for a booster for either setup.
Also, my 94/95 unit's inlet/outlet lines exit towards the engine (inboard side).

Last edited by BobE (9/15/2018 9:30 AM)


65 Fastback, 351W, 5-speed, 4 wheel discs, 9" rear,  R&C Front End.
 

9/15/2018 11:49 AM  #5


Re: Master Cylinder Advice

I might have that 100% backwards Bob.  Its odd on the bore, sometimes I see it listed as 1", others as 15/16".  I could measure mine I suppose (still sitting in a box)...

 

9/15/2018 2:57 PM  #6


Re: Master Cylinder Advice

Any thoughts or experiences on the Wilwood master, or should I plan on staying Ford.

     Thread Starter
 

9/15/2018 5:50 PM  #7


Re: Master Cylinder Advice

602Raptor wrote:

Any thoughts or experiences on the Wilwood master, or should I plan on staying Ford.

 
I would stay Ford. Try buying a replacement Willwood anything from a parts store when you're miles from home. I've got 08 disc front and 2017 discs rear on my 66. I'm using a mc from a 2000 Mustang  v6 without traction control. Booster is from a 89 Mustang 4cyl. Works great. A 92 Ranger Mc will also work. Either may not be as pretty as a Willwood but they're more economical and do the job. Just make sure the gap between the booster pin and the mc plunger is right. My booster is non-adjustable so I had to use shims between it and the mc.


"anyone that stops learning is old, whether at twenty or eighty"Henry Ford
 

9/15/2018 8:06 PM  #8


Re: Master Cylinder Advice

Street driven or race track?  You cannot do it perfect for both applications. That said, I would err on the side of making it as comfortable as possible on the STREET, where it will surely see most of its use.

That means a booster system with a 1” bore disc/disc master cylinder.


Money you enjoy wasting is NOT wasted money... unless your wife finds out.
 

9/16/2018 5:33 AM  #9


Re: Master Cylinder Advice

BillyC wrote:

602Raptor wrote:

Any thoughts or experiences on the Wilwood master, or should I plan on staying Ford.

 
Just make sure the gap between the booster pin and the mc plunger is right. My booster is non-adjustable so I had to use shims between it and the mc.

Can you explain the process to check the clearance between the booster pin and the mc plunger? And what is the “ideal” clearance you want?
 

 

9/16/2018 8:21 AM  #10


Re: Master Cylinder Advice

Chaplin wrote:

BillyC wrote:

602Raptor wrote:

Any thoughts or experiences on the Wilwood master, or should I plan on staying Ford.

 
Just make sure the gap between the booster pin and the mc plunger is right. My booster is non-adjustable so I had to use shims between it and the mc.

Can you explain the process to check the clearance between the booster pin and the mc plunger? And what is the “ideal” clearance you want?
 

 
I'll let MS weigh in on that. My process was trial and error. I had a 67 mc on it to begin with. Didn't like the way it looked so I put the 92 ranger mc on it. Still had the drums out back at this point and they kept locking up. That's when I switched to rear discs. Still locking up. When I switched to the 2000 mc I noticed the booster pin was to long so I shimmed it and it works great.


"anyone that stops learning is old, whether at twenty or eighty"Henry Ford
 

9/16/2018 8:50 AM  #11


Re: Master Cylinder Advice

MS wrote:

Street driven or race track?  You cannot do it perfect for both applications. That said, I would err on the side of making it as comfortable as possible on the STREET, where it will surely see most of its use.

That means a booster system with a 1” bore disc/disc master cylinder.

I’ll take the advice given.  Can I get your pedal assembly and booster combo with a stock clutch pedal?
 

     Thread Starter
 

9/16/2018 1:38 PM  #12


Re: Master Cylinder Advice

I did a little internet sleuthing and figured out how to measure for clearance. Most sources said clearance should be apx. .020. I measured a few times and had a range of .019 to .030, depending on where on the master or booster I measured from, so I am going to call that good unless some suggests a different clearance would be better.

 

9/16/2018 3:42 PM  #13


Re: Master Cylinder Advice

You want clearance as close to zero as possible. I like no more than about 0.015”.
It is difficult to measure!  My method requires no measurements. Just adjust the rod too long until the mc rocks on the rod without sitting flat on the booster. Then adjust the rod 1/2 turn at a time and retest to see if it still rocks. On the final test where you no longer feel it rocking, adjust 1/4 turn shorter and it will be perfect.

Just tell Michael at MustangSteve what you want and he will provide exactly what you need.


Money you enjoy wasting is NOT wasted money... unless your wife finds out.
 

9/16/2018 7:56 PM  #14


Re: Master Cylinder Advice

MS wrote:

Street driven or race track? You cannot do it perfect for both applications. That said, I would err on the side of making it as comfortable as possible on the STREET, where it will surely see most of its use.

That means a booster system with a 1” bore disc/disc master cylinder.

MS,
I run this combo on my race car too and it is perfect! Same caliper piston areas and all. Street car is same and just as good.! Brake pads are a little different so my balance valve to rear is set a little different but still a great set up.

 

9/17/2018 6:09 PM  #15


Re: Master Cylinder Advice

MS wrote:

You want clearance as close to zero as possible. I like no more than about 0.015”.
It is difficult to measure!  My method requires no measurements. Just adjust the rod too long until the mc rocks on the rod without sitting flat on the booster. Then adjust the rod 1/2 turn at a time and retest to see if it still rocks. On the final test where you no longer feel it rocking, adjust 1/4 turn shorter and it will be perfect.

Just tell Michael at MustangSteve what you want and he will provide exactly what you need.

 
Thanks.  I'll give your method a whirl and see how she goes. Appreciate it.

Last edited by Chaplin (9/17/2018 6:09 PM)

 

9/22/2018 1:34 PM  #16


Re: Master Cylinder Advice

MS wrote:

You want clearance as close to zero as possible. I like no more than about 0.015”.
It is difficult to measure!  My method requires no measurements. Just adjust the rod too long until the mc rocks on the rod without sitting flat on the booster. Then adjust the rod 1/2 turn at a time and retest to see if it still rocks. On the final test where you no longer feel it rocking, adjust 1/4 turn shorter and it will be perfect.

Just tell Michael at MustangSteve what you want and he will provide exactly what you need.

Well, I had a little time today and I tried your method.  After adjusting per your instructions, I measured again just to compare and I measured .017 to .020 depending where I measured, so your method closed up the gap a bit from where it was out of the box and was super easy to do. Thanks!
 

 

Board footera


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