Master Cylinder To Use With Herm Mount

Hello,
Earlier this year I picked up a dual reservoir master cylinder kit from Herm for the early CJ5. I'm using drum brakes. I got the mount installed just fine and the master cylinder mounted and bled. Problem I'm having is the thing leaks like a sieve. I think I finally got the banjo bolts to stop leaking. It was necessary to tighten them down to within an inch of their life. The big problem is the cover. It's clearly too small. Herm sent a replacement and it was still clearly too small. When you set it down on the reservoir it's clearly metal to metal contact and not sitting on the rubber. I called Herm again and he denied anyone else ever has problems and wouldn't discuss is beyond saying to send it back.
It's difficult to pinpoint exactly what leaks as fluid gets everywhere. I'm pretty confident it's the cover and not the lines. The problem occurs only while driving and irregularly at that.
I'm sick and tired of fighting with this thing. It's been a nightmare and I've spent about 5 times as long working with it as it should have taken and I still have a problem. Does anyone else make a master cylinder that would be compatible with this kit?
Thanks,
Ken

 

Post pics.
Send back to herm.
Post results here.

 

I have the same question for a different reason. I bought my CJ5 6 years ago and the PO had a kit from Herm and it sat uninstalled I bet for at least 5 years before that.
I'm thinking I should get a fresh master before doing the upgrade. I have drums in all 4 corners.

 

I have also seen some master cylinder lids that just don't fit right.

 

I am waiting for you to get it sorted out, Ken. I plan to the upgrade, but in no hurry. I see so many duel master cylinders, I want to do it right the first time. Good Luck

 

I was under the impression that it is just an intermediate jeep master cylinder.

 

Yea, Herm takes criticism REAL well. I inquired about his master cylinders once. His response was enough to ensure I wont touch anything he makes, even through a reseller.

 

That would make sense.

 

Thanks for the replies. I was just looking for another source for a cylinder that would work. Interesting about the intermediate CJ5. It's worth a try. What year Jeep would be good to look up?

 

I just went to Rock Auto and looked at a 72.

 

Cool thanks. Oriley will supposedly have a rebuilt one for me at 10am tomorrow. Will be interesting to see how it compares

 

Hello kenb,
What year is your CJ5 ?. Which system one is trying to adapt to makes a difference , IE ; Power vs Manual ?. The size of the Piston Bore for
drums /drums should be 3/4 "to 7/8 ", The reservoirs should be equal size & a 10 # Residual Valve is used. Pirate Jack's is a good place for Master Cylinder's ' from my experience. Stay away from Cardone's , if you can. Foreign made defective junk & brake fluid all over the place, just makes brake work way worse than it has to be. Also, Here's the guys I used for my disk conversion. Pricey, but excel ant US made qaulity:
Horsepower Sales, LLC

Jeep/F100/Bronco/Scout/K5, K10/Dodge W100, DRUM-TO-DISC BRAKE CONVERSION KITS

 

I'm working on a '54 M38A1, manual drum brakes, 11" front and 9" rear. I have a brake best product coming.

 

Ok.... Let us know what you find. That's a Bosch Company product. FYI , It's made in you know where ? Oh yeah, you probably know this, but Bench Bleeding first , is a must.
Good Luck, going forward on this. I know your frustration ......

 

I got the new master cylinder installed. It was a remanufactured '72 CJ5 unit. The exterior had a nice "surface of the moon" finish as you would expect. This precluded using banjo fittings as the surface where they would seat was extremely rough. I think it may be possible to use banjos on a new unit. The stock photos make it look like they have that area machined smooth.
Regardless, I was able to use flared fittings. The threads are 1/2"-20 so I had to buy fittings and flare the brake lines since the other fittings on the vehicle are 3/8". I couldn't find a prefab line with 1/2" fittings on one end and 3/8" on the other that was long enough.
Dimensionality the unit is very close to what Herm sells so it mounted right up. The rear fitting is very tight with the front end of the bell housing. I used some copper nickel brake line so I could make a tight bend just off the fitting. No clearance issues with the front.
It's very difficult to get photos of this for some reason. None of the ones I took turned out. Will try again.