Early model brake upgrades?

[dharmabum]

I've read alot of old posts on this and am going to be upgrading my brakes soon and wanted to get some opinions from people who have done it already. I currently have the stock drums and single diaphragm booster on my 72. I am going to be putting discs on the front using later Wag/Chevy calipers and the thick 5 lug CJ rotors. I want to upgrade my master cylinder and booster and am thinking of going with the 78 J20 dual diaphragm booster and a disc brake MC. Does anyone know if this booster and MC is a bolt on to the early models? Fab work is no problem but I'm looking for the least down time and best results for my upgrade. Thanks for any info. :D

[kidatforty]

Dharmabum, wuz-up. I don't know if you remember, but my 69 wag has discs on front. I thought it was a stock option till everyone pointed out that the set-up is off a CJ-7. I don't understand why you need to change master and booster. The set-up on mine is totally adequate. When you say dual diapragm in the booster does that mean that it has two rubber diapragms in it? What would that do? I've never heard of that. I know that early cars had a single piston master cylinder and later had dual piston for safety so that you don't run out of fluid if leakage occurs in front or back. I'm just interested in learning more info. on what you're talking about. Just to let you know, my brakes were put to the test one day while driving in city traffic. Some DS lady decided to join me in my lane ( without signaling or looking). I just knew she was going to do this and I hit the brakes hard and it stopped beautifully and saved both our butts not to mention all the parked cars on my right. Sorry not to answer your Q. It will be interesting to see replies.

[dharmabum]

Hey kid, hows the new motor coming? I plan on doing the same disc swap on my Wag, done it before on my Commando and a CJ. My booster is pretty marginal now, low pedal, etc... but the motor has 19 lbs of vacuum. The dual diaphragm boosters, as I understand, provide more assist and are a better design than the early ones. They were optional on J20s in the 70s and became standard equipment on Wags in the mid 80s. I figured why replace what I have when I can upgrade to better. smile.gif My brakes work ok and the pedal will pump up good but I dont trust them to tow anything or make a real panic stop. The dual outlet MCs are supposed to keep the brakes working if there is a leak in one of the systems however my brother lost all his brakes the other day when he ripped off a line on his TJ so I don't know how much I believe that?

[kidatforty]

Hey. The new motor is here. Check general discussion. I posted there. Good luck with brakes. It sounds logical to me. I'm signing off now. I want to go service my wife. Later......

[Baldy]

The single best brake upgrade I've done was a dual diaphragm booster/mc off a 78 J20. It bolted directly in place of my old one...but then my waggy is a 79. HTH

Laz

[dharmabum]

Thanks I figure I'm just gonna get the parts and do it when I do the disc conversion, if it needs some fab work than it'll just take a little longer.