Disc brake conversion, thicker inner race and snap ring

Not necessarily true although it can be in some applications. I'm running discs front and rear with GM 1/2 ton calipers at all 4 corners. I'm running the stock single reservoir M/C for my '59 CJ-5 with through the floor pedals. I move the pedal 1-1 1/2" and all four are locked up. I've been running it this way for around 15-17 years with NO issues. I would recommend going to a dual reservoir m/c for safety purposes but it is possible to run the stock m/c if in good shape with disc brakes. Also, the larger the bore of the m/c the more fluid you will push as you noted, but the less pressure that will be generated to the calipers. You have to balance the piston size in the m/c to the piston size in the calipers. Pascal's Law of hydraulics.

 

According to the research I did so far, there really is an elusive dual reservoir side mount MC that is just like the Single you mentioned. I also saw it listed in the O'Reiley parts book (in the store, not online) as a Raybestos #36365 and it clearly said in the notes "frame mount dual reservoir" It was listed for a 67-71 CJ directly below the single pot MC listed for the 49-66. Apparently there isn't much demand and it has been discontinued or something as they are very hard to find, are always out of stock and list for hi $$$. Most of the web sites show the same picture you posted for it (which doesn't show any side holes) however I did see one site somewhere that had the correct picture of the side mount with 2 chambers so I know it exists.

It seems this is a common problem and like others I will probably have to come up with some sort of bracket. However I don't have a blue wrench or welder to fall back on.

As to the piston size, would the OEM GM size for the year of the caliper be a reasonable choice? If so does anyone know offhand the size of the MC piston in a 77 K-10?

 

like I said, it's not a law of nature, and I wouldn't recommend running *your setup*, although obviously it does work. you *can* do it, but I'm not sure it's *right*

 

I think this _might_ be a pic of the one I was thinking of (he mentions it is a 67-71) but, it too needs frame/bracket work to be mounted.... so I may go with a newer model.

http://www.film.queensu.ca/CJ3B/Tech/BrakesDualMaster.html

 

I'm wondering where you got the 1" or preferably 1 1/8" or larger bore diameter? You can't know what size m/c bore diameter is *right* without knowing caliper bore sizes and/or wheel cylinder bore diameters. Using Pascal's Law you can figure out the needs, but without those sizes you can't "know" what size you need. I wouldn't recommend running any combination without figuring this out or it wont be *right*.

 

The Dorman and NAPA replacement M/C for a 77 K-10 uses a 1 1/8" dia. I know other things like weight will enter into the sizing but that should be a good starting place. Since the stock 66 uses a 1" bore and more volume is said to be required by disc calipers (in general) I am wondering if the 7/8" bore of the "recommended replacement" is sufficient.

Apologies to 68 Swamper for hijacking the thread.... probably should start a new one for MC selection.....

Al

 

Syber4x4, is that m/c for the '77 K-10 for power brakes? If so your pedal pressure to operate the calipers may be very high, i.e. hard pedal with minimum movement but poor brake performance. The larger the bore of the m/c the more fluid you will push to the calipers/wheel cylinders but the less pressure will be generated. Manufacturers can do this to keep the pedal high and have good brake performance because of the power assist of the power brake booster.

 

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Apologies to 68 Swamper for hijacking the thread.... probably should start a new one for MC selection.....

Al[/QUOTE]no apologies needed, I am learning just like you, I did finaly find ot the jeep will do 55 and stop, thats a good feeling

 

The MC for '77 K-10s is for power brakes.

I have just finished a disc conversion and have found a dual reservoir 1" bore MC to be quite sufficient. A slight tap and I slow down, 3" and I'm lurching forward in my seat.

Here is my research on MC and WC bore sizes:
Vehicle MC Notes Front Bore Rear Bore Difference
J54 stock 1" manual +9 f +9 r
66 CJ-5 1" manual 10 f 10 r 1.0000 0.8125 0.1875
75 CJ-5 1" manual 11 f 11 r 1.1250 0.9375 0.1875
78 CJ-5 1" manual 11d f 10 r A 0.8125
78 CJ-5 1.0625" manual 11d f 11 r A 0.8750
78 K-10 1.125" boosted 11d f +11 r B 0.9375
Sgt Betty 1" manual 11d f 11 r B 0.9375

11d means disc brakes. A and B represent unknown caliper bore sizes.

 

Experience, more than anything else, I've never seen anything smaller than 1" recommended for a Disc/Drum setup, while I'm new to jeeps, I've worked on mods for plenty of F-Series pickups, Mustangs, Camaros, and Street Rods. I'm certainly no engineer or mathematician and haven't the foggiest how to calculate proper fluid flow for a given system, but this has been a pretty accepted standard in the circles I've run in, when putting disc brakes on something that didn't originally have it.

I could be all wet, it wouldn't be the first time, but I've never had sub-par brake performance on anything I've built by following this rule.

 

Continuing to pound my head ...:dead horse:
I made up a comparison spreadsheet with about 29 different part numbers shown as compatible for 65-76 CJ's as sold on various websites. Then I started eliminating some for various incompatibility preferences.

One thing I sorted out was that Raybestos 36365 and Crown 945556 parts are elusive to find and cost between $107-$260 when you find them listed (not necessarily in stock). Although they are listed as frame mount, they seem to have the ears at the back and no thru-holes, so technically I wouldn't call them frame mount as in the 49-66 original equipment. From reading posts over on Binder Planet, I deduce that these use a stepped piston (7/8"-1") and thus the reason for their cost and having been generally discontinued.

What I finally came up with... was exactly the same part numbers as Steve recommended.

All have a 1" bore. I haven't compared them to see if they all have the stoplight switch port, but that detail can be plumbed any into the new brake lines that all of them might require to get proper connection. All will probably require some sort of mounting bracket and possibly alteration to the push-rod. The good news is they are generally under $45. Now to find a prefab bracket....

 

Hermtheoverdriveguy has a kit and I think there was a bracket and what not in the classifieds

 

Thanks but that is too much $$$ - I'm on social security and have to watch every cent now. I'll check the classifieds, thanks