Herms dual master cylinder kit

Has anyone installed this and what probelms did you find or run into? My body is ready to come off and i will be needle scaling the frame and want to upgrage the brakes a little.

 

I put one in this winter while I had the body off. It's more or less a drop in, but I did have some issues with alignment between my brake pedal push rod and the MC. It could be that my brake pedal isn't right, or maybe all flatty brake pedals are just a little different than the CJ-5 ones. I don't know. But in my case, I needed to shift the MC inboard a ways to get it lined up with my brake pedal.

I was able to just open up the holes (a lot ~3/8-1/2") in herm's bracket, eventually it all went together. Your other option might be to put a little steeper bend in the factory pedal or do something to extend the post that sticks out of the side of the factory pedal. Or maybe mine was just a fluke and you won't have any problems at all!

Originally I shifted my pedal the 3/8" (towards the frame) which also works, but found out later when I put my (Ross) steering back in that there wasn't room for the pedal and the steering tube in that position.

There are a few things you'll need to get.

-clutch pivot bracket for a CJ-5 (though the ones they sell for the flatties happen to be the same part, go figure). These are ~10 bucks and Herm may have them available when you get the MC kit. You'll need to cut your old bracket off the frame, drill two holes and then bolt up both the new bracket and the MC bracket. You might also want to get a new clutch/brake arm pivot shaft, though in my case my old worn out one actually fit better/had less slop than the new one I bought (so I reused the old). There are minor differences between the two, but either will work.

-1/2" thread brake line fittings (I wasn't aware of these at first and I originally used adapters down to my 3/8" brake line fittings, but there wasn't room for the adapters and brake lines and my engine--found this out when I tried to install the engine/bellhousing). I also tried Herm's banjo adapters, but they didn't fit either. But plain 3/16" brake line with the "big/drum" style 1/2" fittings will work. Part of the reason I had so little room is because I had to shift the MC 3/8"-1/2" inboard so that it would reach my pedal.

I'm really curious if a CJ-5 brake pedal arm wouldn't solve a lot of problems (that I had).

Here it is halfway to working. You can see that the MC still needs to move to the right, or the pedal arm to the left to make this work. With the pushrod hooked up to the pedal arm the pushrod would bind up against the back of the MC.



Here it is in finished form:



End result, it does work well. If you are already running 11" brakes, I'd recommend going with stock bore size on the wheel cylinders for a 76 CJ-5. That's what I did and they seem pretty well balanced. (the reason I went that route is that this year jeep also happens to use the same bore size MC as provided in Herm's kit)

 

thanks that looks easy enough. ill be ordering it this week.

 

PM godevil on his experience with that same kit, just incase he dosnt see this thread. I know he just installed one on his flattie and had all kinds of problems, not sure if they were the same as the ones mentioned above or not though.

 

I have just installed one and it fought me pretty much all the way.
No offense to Herm, it is a great product and I am now glad I have made the conversion but it is definatly not a "drop in".
You will have a much easier time with the body completely off,I just jacked mine off the frame, but their is trimming neccisary on the body too when you go to put it back on.
PM me and I will give you my phone # if you need any help with it.
Donnie

 

Would it be an easier install with a aftermarket master with remote reservoir? They usually have a slimmer body.
Keith

 

I put one in an m38. I didnt have to trim the body at all. we did have to modify the bracket a little. We welded it in instead of bolting. the hardest part was getting the linkage to work.

 

I've done an 11" conversion on mine too but haven't gotten around to changing the MC yet, which is causing Incredible Hulk-looking right leg. Obviously not generating enough line pressure with the original MC bore size.

Anybody have any info on what the MC bore size would go with an 11" drum? After reading this I'm leaning toward aftermarket MC with remote reservoir....

 

Maybe when I said a "drop in" I was letting the months since install soften my experience a little. It took me about 4 or 5 various evenings to get it working right, and it seemed like I was fighting a losing battle there for awhile. But if you take some of my lessons learned listed above (and do a dry fit with the steering box installed, just use c-clamps) and post your problems here where we can help you'll save yourself a lot of headache.

I did not have to trim my body any, but the body support/channel is very close to covering up the cover on the MC. Maybe because I have mine moved inboard I didn't have a problem there?

I'm not sure that this MC will help you out much in the "pedal effort" category. Stock bore size is (I think 1") and as far as I know, his drum brake MC is also 1" bore front and rear. I asked him once and wrote it down, don't have the note handy, but that's what I remember.

For 11" brakes on all four wheels, I'm using stock 76 parts, which is 1-1/8" on the front and 7/8" on the rear. (the 76 MC is also listed as 1" bore in the various catalogs I've looked at. I'm almost certain it's the same part he sells).

In my opinion it stops fairly well, and if you really put some leg into it (with the right tires) it sometimes feels like you could pick the back up off the ground. But they definately aren't like a modern car where you can just rest your foot on the pedal and expect it to do something.

The high effort your system takes might just be due to semi seized up MC or wheel cylinder(s). I was a little shocked at how rusted up all of my old cylinders were when I redid my brakes. It took a 4lb hammer and a drift to get the pistons to move on a few of 'em. (but the brakes worked great before! I have no idea how).

Bottom line, would I do it again if I could do it over? Yep.

 

I bet the issue is the top clearance being snug during the install? That is a nice looking kit he put together.

I have a Wilwood single cyl with a remote reservoir tank. Makes the install tons easier without the reservoir getting in the way. I also installed one on another 2A and went on without any wrench throwing. Wilwood is good stuff which the dirt roundy-round racers typically use.

Wilwood now makes a remote dual cylinder universal (side or end mount). Two cylinders is best

 

Wonder if there would be room to mount twin singles there with remote reservoirs. I have heard that twin singles, instead of one dual, work better than power brakes.
Keith

 

I assume that Herm's kit duplicates the setup used on the CJ5 with dual M/C. I pulled the brackets of the old 69 I had and installed it on my 46 2A. Didn't have any problems.

 

When I did mine the only problem I have run into so far was the push rod, it was WAY to long. To I ended up making a new one from a 7/16 bolt UNF (I think) and some round steel tube. I reused the end that goes into the MC (the end with the round tip),

I haven't ran the brake lines yet so I hope the supplied hardware clears it. Also it's REALLY close to the steering box, but it down squeeze in there.

I have one questions, where do I mount the brake switch? Would I just install a junction somewhere and run it off of that? I would assume it's the same difference.



http://www.ottawajeepclub.ca/photos/gallery/main.php?g2_itemId=19277

 

The original dual systems on the Jeep had a brake light switch on the front and the rear lines. Just put a junction in the front system some where as this one activates first.

 

Thanks, the fact that the front comes on first wouldn't have clicked, good info.

 

The MC I got from Herm had a 1/8" NPT fitting on the bottom. Just thread the old original switch in there and you are good to go. I broke my switch during the install and went to a later model one (for a 60's CJ-5). It has lower profile terminals which look a little less prone to breaking off than the bullet terminals that my original had. I used female blade crimp connectors with some creative heat shrink tubing to keep the two connectors from bumping each other... seems to work fine.

It does still look a little prone to trail damage though, we'll see. After having one of my oil filter lines break the other day, I think I'll make it a point to always carry an extra 1/8" NPT pipe plug in the tool box.

 

you're a wise man R)
SOP for Jeep spare parts

 

Has anyone figured out a way to do power brakes with the floor pedals? I would love to have them but want to keep the floor pedals.
Keith

 

I used herm's bracket with a MC from flaps (64-71 CJ with dual wheels) from wagner (got the part number somewhere) it came with the push rod installed. All I needed to make was a bushing to fit the pedal.