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striker
03-23-2008, 09:00 PM
If this topic is in the wrong place??sorry..

I was wondereing if anyone has had any success with disc brakes on an amc 20. Being the after market kits were way out of $$ range I opted to put my own together. I've done hours of homework searching the net. so i know there are endless options, but I am looking more for personal experince. ( what did you try that did or did not work). I went with mid 80's 300 zx calipers with side kick rotors. install was pretty staight forward. while this is better than stock drums it still leaves room for improvement. everything else is still stock. am thinking about the vette master cylinder and a dual booster, but I like input. especially when I'm weak in a area suchas brakes.. thanks ahead of time..

ironman_gq
03-24-2008, 04:57 PM
find a master cylinder out of something that had four wheel disc brakes and dont even worry about the booster, or get a mini booster and an mc that came from something with boosted four wheel discs.

tufcj
03-24-2008, 08:07 PM
I have a 44 in the rear of my CJ, converted to disc with a kit from TSM ( www.tsmmfg.com ). My CJ was factory power front disc/rear drum. I'm still using the factory booster and master, and it works great. The only time I've ever had the rear lock first is on icy road, so I think the balance is just about right.

Bob
tufcj

striker
03-24-2008, 08:25 PM
I thought about not doing the booster, but after all the research I've done I don't think I could make enough pressure with the pedel ratio and my legs. besides, I feel like the work should be building the jeep not driving the jeep. as far as the balance i wish i could say it was good like yours. where i should have a 65/35 split, I think I'm more along the lines of 85/15. under heavy braking fronts are just a hair off locking up when the rears are just getting started. Did your brake kit not suggest any change of any other braking componets?? oh, and is your jeep heavily loaded with 35's (or bigger)? I put 35's on mine but is still pretty light, I think. well there is a hard top and roll cage but?? I don't know, just grasping for straws. thanks for your input guys. I think I will try the 69 'vette m/c. I'll get back to the post after this weekend, when I can change it.

dwg86
03-25-2008, 06:08 AM
I have 4 wheel disc on my 79 cj5. I used the brackets for the rear axle that came with the full floater kit I installed. I used 1979 Cadillac rear calipers and proportioning valve. Master cylinder is a 4 wheel disc for a 1979 ws6 trans am. I used a dual diaphram booster for 1984 S-10, bolted to the original jeep power booster brackets. The holes have to slotted about 1/4 inch to fit the booster on the brackets. I also made an adjustable input rod from the brake pedal to the linkage that goes to the power booster. Works Great! and it didn't cost much...Calipers and prop. valve from local pull-a-part $30.00, S-10 booster from evilbay brand new in box $10.00. 401 powered with 36 inch tires will stop on a dime with no effort.

tufcj
03-25-2008, 07:45 AM
Mine is fairly well loaded in the rear. I have a storage box that fills the rear area. In that box is a full set of axles (4), 2 drive shafts, tool set, fluids, winch kit, tow strap, and supplies for the onboard welder. My tires are 37", and I have a 37" spare on a home made swing out on the rear bumper.

My front 44 has F-150 rotors using Wagoneer calipers. I'm told the rear TSM rotors are a Lincoln application with some machining done, rear calipers are GM e-brake type.

I can get the fronts to howl on hard braking on the street without locking the rears, but I can feel that the rears are doing the job. I'm quite happy with it's stopping capability on and off road.

Bob
tufcj

striker
03-25-2008, 07:56 PM
are the waggy calipers and ford rotors any better than the oem front disk? that also "sounds" like a pretty staight forward install with lots of room for growth. And its not like my braking is bad, I just don't have that panic stop if I need it. I don't know if any of you guys know the area but I'm building my jeep to handle hotsprings Arkansas area.(large, steep, rocky, wet hills) That and a little fun driving down the street.

tufcj
03-26-2008, 07:38 AM
Ford rotors and waggy calipers are bigger than the 79-up CJ brakes (1 1/8" thick vs. 7/8"). They are the same as the 76-78 CJ "big brakes".

I just went that direction to keep the 5 on 5.5" lug pattern when I did the front Dana 44 conversion. The best upgrade for the Dana 30 would be the 76-78 brakes. You'd need the rotors and hubs, calipers and brackets and the outer knuckles, maybe even the spindle, but I'm not positive.

Bob
tufcj

striker
03-27-2008, 08:20 PM
so I did get around to changing the mc to the 69 vette. ouch. yeah, my brakes got worse. sooo I researched some more. and according to the great net I should also change the proportioning valve to a disc/disc valve. maybe so, but I would have thought the brakes would have increased a little or even stayed remotely close to what they were, not worse.

striker
04-01-2008, 08:01 PM
For the guys that helped, thanks! I was able to get the brakes working and their better than ever. It turns out the brakes were not nearly as bled as they should have been. I went through another two 32oz. bottles. I also had to upgrade my booster to a larger size (7 inch stock - 9 inch dual). In the middle of this I had "trash" in my carb which led me to believe I had a bad booster or vacuum leak. I may end up going to a 8 inch dual to return a little more firmness to the pedal. Like I said thanks for your input and help.

80cjinnc
05-10-2009, 06:53 PM
I just seen your post and I see it was last year but if you are still thinking about rear disc on an AMC 20 I just completed mine with the stock MC and it will about put you in the dash. I am running 36's and it would hardly stop before. Check out post http://www.bulltear.com/forums/viewtopic.php?t=9311

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