B3B Replacement Master Cylinder

[desmondmonster]

hi everyone,

 

I recently came into a 1951 B3B Pilothouse.  It runs ...sort of... but planning on doing a major overhaul.  Also, this is my first restoration project, so taking it as a learning experience too.  I apologize in advance for any painfully newbie questions.

 

Anyway, there's a rupture in the brake line somewhere and the pedal has zero pressure.  I'm replacing most of the brake system and going with Rustyhope's front disc conversion.  So far so good.  The question is: what have folks here used as a replacement master cylinder for the disc/drum setup?  I know the original MC *can* work, but mine's not in great shape and I figured a new dual cylinder would perform better anyway.  What experiences have others had?  Is it a pain to run another brake line from the cylinder to the front wheels?

 

thanks

Desmond

[bach4660]

when I did the rusty hope disc conversion I went with a 7" brake booster with dual master attached, also I had a proportioning valve from a Chevy nova that I used to get the disc/drum pressures.

[pflaming]

I used a 98 Cherokee master cylinder and proportional valves. Bee four years no problems. But the space is VERY tight the pic shows the setup. 

Edited June 16, 2019 by pflaming

[pflaming]

This is a car setup,. But the back to back master cylinders is the same. 

[desmondmonster]

@bach4660 is the proportioning valve necessary? Did you have trouble fitting the piece into the small space?  Did you replace your entire brake line as well?

[pflaming]

Yes, yes, and yes. The calipers on the disc brakes differ so much from the OE drum cylinders that the valves are IMPORTANT. Now, without the valves there will still be braking power, but much less so. With the new soft brake i

lines now available, the fitting will not be difficult. I would buy the shortest possible and keep the professional ends.

 

New brake lines, for certain. When I discovered the new line material, I removed all the steel lines I had made and replaced them in two hours. Again the new soft lines are the only way to go. If you buy a variety of lengths,  you can place where fits best and use all factory ends. Lots of way to shorten a line that is too long without having to cut it. That is a cosmetic decision.

 

Good luck. This shows steel lines which I replaced.

luck.

[desmondmonster]

thanks, i'll pick up some of the copper brake line find a proper MC/valve and report back.

[tanda62]

I used Nickel copper lines and found them easy to use with one word of caution...bend them slowly and carefully as they love to kink if you even look away for a moment.  They bend without complaint but if you move to fast they will kink.  Also be careful when doing the flares as they are soft and again slow wins the day.  Good Luck!

 

Here are some pics of mine: ( note I routed the front behind the transmission and then up the frame rail rather than in front of the engine as stock)

 

[Old CWO]

On 6/15/2019 at 3:59 PM, pflaming said:

I used a 98 Cherokee master cylinder and proportional valves. 

 

I have the same - 99 Cherokee.  It is indeed a tight fit, but it works well, is affordable and came from a Chrysler product...

 

Don't care for the "modern" plastic reservoir,  but it's tucked down there low enough you don't really notice it.

[desmondmonster]

@Old CWO did you put a booster on as well?  not sure how/where that would fit in.  any issues with the mounting screws?

[Old CWO]

No booster, manual brakes. The only way I see that you could do a booster is if you went to a hanging pedal.

 

There is a little custom fitting involved with swapping to a modern MC but it isn't too bad.  

[bach4660]

On 6/15/2019 at 4:46 PM, desmondmonster said:

@bach4660 is the proportioning valve necessary? Did you have trouble fitting the piece into the small space?  Did you replace your entire brake line as well?

I put the booster under the cab, it take some custom work on mounting plates. I purchased booster, master and pedal as an assembly

the proportioning valve went into the frame rail under the drivers seat. The only problem with this set up is to access the master for filling I had to remove the tranny cover plate.