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Well I learned most of this through what Bigdude has done to his YJ to upgrade his brakes. I know that there are a Few of Us ZJ guys on here and I thought that I would post it for all to read.

Ok I will have a write-up and pictures some time this week.

Here is the skinny.

2.22 for a 2 to one compression coupler.
.33 cents for one fitting.
25 dollars for a Reman 1986 E350 Master Cylinder.
10 bucks for a 1988 XJ booster.

Kung Fu Brakes......Priceless

Bypassed all ABS, dumped the proportioning valve. Connect the two front lines into one line via the coupler and retrofit the one rear line with the new fitting to correspond with the rear chamber of the E350 MC. All parts are easily sourced at CRAPA (Napa).

ZJ booster will not work with the E350 setup. It took me about .02 seconds to see that when I got all the parts in hand.

The XJ Booster is a direct bolt on. No fuss no muss.

Drill the E350 mounting holes out to 9/16 and take just a hair off the outside edge of the ears and it fits right on the XJ booster. Bleed the MC and hook up the lines. Bleed as normal. Enjoy the best braking that your ZJ has ever had, the difference is Amazing.

Next to the Front Long Arms this is possible th esingle most rewarding day of wrenching I have put into the ZJ yet.

Kung Fu Brakes ROCK! (that is term coined by my buddy when we pushed on those things the first time!)

Be forwarned this Mod is not for the light of heart and if done properly will easily lock up a 36 inch tire at speed.
 

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Thanks, for the info. I have hated my brakes for a long time, I lost the ABS with the axle swap but left all the plumbing in place. Just waiting for someone to try a different MC so I didn't have to guess what would fit. Looking forward to your write up. Do you think you will add a proportioning valve down the road or does the front to rear braking seem pretty equal?
 

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Well they seem to be stopping and applying just about 50/50 which is just what I like for my application.

Basically the above post is going to be the writeup but I will add a few pictures......
 

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Kung Fu brakes, I like that. Seems very fitting to the throw you through the windshield feeling :D
 

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Yo alasker-

This is hilarious. My GF got pissed at me yesterday because I stopped making out with her because I didn't want to miss a Baer M/c and booster swap on Speedvision. Later in the day, when I was pulling the block on the GF's Scout, I took a break and had a 10 minute brainstorming discussion with my mechanic/salvage friend about brake upgrades. Anyway, yesterday, I was thinking heavily about new M/C's and boosters, but not sure what would work - thanks for posting this recipe!!! It's EXTREMELY timely!!!

Cheers
Bob
 

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Bigdude- Yah that is a good description. A buddy of mine said it when he was backing it out of the shop and squealed the tires stopping....great stuff.

Trango- I am glad someone is benefitting from my writeup (sorta) and others ingenuity to try it out first.
 

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Here is the 86 E350 MC and the 88 XJ booster mated together and installed in my 93 ZJ.



Here is the ZJ MC. Notice how the pushrod is part of the MC via some kind of funky tube. It is part of the MC and not removable without a bunch of work.



Here is the ZJ booster. Notice how there is no pushrod sticking out the end. It is a funky setup with a short nub of a rod inside. The XJ booster mounts right up with no modification to the old ZJ spot. Even attached to the pedal exactly the same way.



Here is the XJ MC. It looks just like the E350 setup. However the mounting holes on the E350 need to be drilled out to 9/16 and a hair shaved off the outside of the ear.



Here are the SOA YJ lines I used to get a bunch more leangth. Even at full droop with no shocks they are WAY long.....



Here is the Part Number of the E350 MC. 25 bucks!



Here is the joining of the two front lined and it totally bypasses all the ABS junk. I am not running a proportioning valve either since I want my brakes working about 50/50 anyway.

 

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so you used a '88 booster. do you think he E350 MC will make much of a difference on an '88 XJ? or do you think it was the combination of the MC and Booster on the ZJ setup that made the biggest diff?


My '88 could always use some help in the brakes.
 

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Does anyone know what the thread count and diameter for the lines going into the stock master cylinder? It would be nice to just use line adapter as apposed to cutting lines and flaring for new fittings.
 

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Wes in TN said:
Does anyone know what the thread count and diameter for the lines going into the stock master cylinder? It would be nice to just use line adapter as apposed to cutting lines and flaring for new fittings.
I got the adapter lines for the E350 master at Discount auto parts. I'm sure any parts store will have them. I think it was $5 for the front and rear lines that adapted the E350 to the stock YJ proportioning.

For reference the YJ booster is the same as the XJ and just changing the master made a hell of a difference and locks up my dual pistons and 14 bolt drums just fine.
 

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Looks like i know what i'll be doing soon :D :D

Bigdude: so you hooked up the E350 M/C to your stock YJ distribution block? I was thinking of trying that or going with an adjustable proportioning valve. I have discs all around now but don't want to be locking up the rear all the time.
 

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xj4rocks said:
Bigdude: so you hooked up the E350 M/C to your stock YJ distribution block? I was thinking of trying that or going with an adjustable proportioning valve.
I can actually lock up my 14 bolt drums before my front dual piston calipers when I really stomp it hard. I figured no harm in trying it first with the stock proportioning valve since the cost of the adapter lines was ~$5 and they are easy to run at only 6" long. For about $30 and maybe an hours time you might as well leave the valve there and see if you like it. If not then try the o-ring trick with the proprtioning valve.
 

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I'm going by the parts store after work to pick up a E350 booster and some fittings to flare onto my stock lines. I can't look under the hood since I'm at work, what size are the stock hardlines, 3/16"? I need one 3/8-24 fitting and one 7/16-20 fitting to adapt my lines to the E350 MC right?
 
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