Jeep master cylinder?

[TylerB46]

Hey guys, a few months ago I installed a rusty hope disc brake kit on the front of my 46 dodge WC. I was thinking about putting a dual chamber master cylinder on it for safety sake, and I've heard that maybe with just a little modification a jeep cherokee master cylinder would fit. Has anyone else heard this or know where I could get a bracket or info on this?

[pflaming]

I mounted an 98 Cherokee dual chamber MC in my B3B. I mounted it in line with the original c. I gutted the original and ran the push ROD through. To do this requires a single spacer mount. I used a 1/2 " steel plate. I deadheaded two bolts to attach to the original MC then threaded three holes to attach the jeep MC to it. A large hole n the center. all these holes and bolts must be perfect. I had a machinist friend do mine. 

 

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[TylerB46]

7 hours ago, pflaming said:

I mounted an 98 Cherokee dual chamber MC in my B3B. I mounted it in line with the original c. I gutted the original and ran the push ROD through. To do this requires a single spacer mount. I used a 1/2 " steel plate. I deadheaded two bolts to attach to the original MC then threaded three holes to attach the jeep MC to it. A large hole n the center. all these holes and bolts must be perfect. I had a machinist friend do mine. 

 

. 

If it takes all that I might just do it later on, but definitely good info and something I’ll keep in mind. Thank you 

[Merle Coggins]

Look again Paul. I don't believe you gutted the existing M/C and ran through it on your truck. I believe you confusing your different projects.

 

Tyler, if you use the search function of the forum this has been discussed a few times. I remember someone finding a M/C that fits with little modification. I just don't recall the application.

[NiftyFifty]

I didn't gut anything on my master cylinder when I did my swap,

 

 

Just be sure to read all the way through

 

 

[TylerB46]

31 minutes ago, NiftyFifty said:

I didn't gut anything on my master cylinder when I did my swap,

 

 

Just be sure to read all the way through

 

 

That’s great info thank you

[TylerB46]

50 minutes ago, NiftyFifty said:

I didn't gut anything on my master cylinder when I did my swap,

 

 

Just be sure to read all the way through

 

 

Do you know if a MC with the plastic resivor is better than the metal with the metal cap?

[pflaming]

Merle, I used the same setup on both vehicles. The Suburban required a cross bar to the frame. All else is the same. Both have proportioning valves.  Those Cherokee MC's are easy to find. 

[NiftyFifty]

Plastic is just fine in that location, and smaller and easy to find

[Merle Coggins]

3 hours ago, pflaming said:

Merle, I used the same setup on both vehicles. The Suburban required a cross bar to the frame. All else is the same. Both have proportioning valves.  Those Cherokee MC's are easy to find. 

 

I'm curious to see how you mounted another master cylinder in tandem to the original one, seeing as how the steering column passes right in front of the stock M/C.

[pflaming]

 You are correct, not in tandem. The spacer / mount was to mount the jeep MC where the original MC was. That was six years ago. . . .

[pflaming]

I took a photo. The jeep MC bolts to the cross member. The jeep MC has three holes, the original had two. So the plate with welded in stub bolts is attached, then the jeep MC bolts to the new plate via three tapped / threaded holes.  Rod from pedal needs to be extended. I put a short hose on to the push ROD and pulled it forward to about 1/16 inch to get the length, then welded a stub on. 

[TylerB46]

6 hours ago, pflaming said:

I took a photo. The jeep MC bolts to the cross member. The jeep MC has three holes, the original had two. So the plate with welded in stub bolts is attached, then the jeep MC bolts to the new plate via three tapped / threaded holes.  Rod from pedal needs to be extended. I put a short hose on to the push ROD and pulled it forward to about 1/16 inch to get the length, then welded a stub on. 

So how much longer  would you say the push rod needs to be?

[pflaming]

If memory serves me correct, less than an inch. 

[TylerB46]

4 hours ago, pflaming said:

If memory serves me correct, less than an inch. 

Awesome, this seems like a pretty simple tast so I’ll definitely give it a try

[pflaming]

Once all installed, slip a short tube over the rod, then move it so it ALMOSTtouches the new MC plunger. Then remove and weld on a stub accordingly. Easy and accurate.

 

i put the proportioning valve along side the MC. THAT is not an easy task, very, very tight space. 

Edited November 22, 2018 by pflaming

[Radarsonwheels]

Man I had a ton of trouble doing one on mine. Maybe I needed a bigger bore- I think I used 7/8” or 15/16” dual pot master from like a dart or diplomat or something

 

I also had the rusty hope setup, but with stock ‘54 drums and an adjustable proportioning valve.

 

I couldn’t get enough leverage to slow down fast with a 1 1/8” or so m/c so I swapped to the smaller bore. Then I couldn’t get enough throw out of the stock linkage- it would either hit the floor before squeezing the rotors hard enough or if I made the pushrod longer it would stop great but then not return far enough to let the pressure out of the lines so after a few stops it would drag then lock up. 

 

Then I added residual pressure valves to hold the drums and prevent flowback so I wouldn’t have to pump up every stop and lengthened the lower arm on the pivot to get more throw for the same pedal movement and I had to angle the MC up so the rod didn’t bind now that it pushed back and up instead of just back. 

 

It was like a saga of not working right and to add to the fun the rear with the quad wheel cylinders for some reason never wanted to bleed easily. 

 

Instead of setting the truck on fire and pushing it into a lake I ended up adding a jeep rear axle with discs and a cheap swinging pedal with a dual diaphragm power booster and 1 1/8” corvette style master. It finally stopped- not like a modern car, more like my ‘86 ramcharger with 33” tires. It would slow quickly and reliably but couldn’t ever lock them up...

 

I have done a lot of custom brake stuff and never had trouble making stuff work like I did with my ‘54. I hope yours works out better- seems like other folks just swapped to a dual pot with no drama.

 

Maybe there was air in there I never got out? I even paid a shop to power bleed it in desperation once...

[pflaming]

Radar: the key might be the '98 Cherokee MC. It's stroke is the same as the OE MC. I've driven mine now for five years with no problems. Best to you. 

[tom'sB2B]

I used a master cylinder from ‘96 Cherokee from a pick-n-pull along with the rusty hope disc brake set-up. Best upgrade   I’ve made.