YJ brake conversion

[Tin Medic]

Has anyone done the YJ conversion that was posted on bustedjeep.com? I have the setup from a TJ and if it will work I will go with that?

 

[Tin Medic]

So, no one has done this?


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[Torxhead]

I have read about quite a few of those swaps with very good results. I'm not sure whether or not the YJ proportioning valve is nescessary though. The thing that bothers me about it is that the lines coming out of the master brake cylinder are on the oppisite side, there are other units available like from Parts Mike where that is not the case.

 

[jonboy1919]

Has anyone done the YJ conversion that was posted on bustedjeep.com? I have the setup from a TJ and if it will work I will go with that?

I did the YJ brake upgrade/conversion on my '79 CJ7 and the results were fantastic! If you have spongy brakes I HIGHLY recommend this conversion. I'm not sure what was posted on "bustedjeep.com" regarding this upgrade, but what I have posted here below is what I followed and it worked great.

I pulled the brake booster, pushrods and the firewall mount bracket from a 1995 YJ. The only thing I purchased new was a 2-stage YJ master cylinder. The YJ MC unfortunately has the brake line ports on the opposite side as the CJ MC. Fortunately, my brake lines had a lot of excess coiled right near the MC so it really was no big deal. Also, the YJ primary pushrod I had was too long, so I cut out about 1/2" in the center of the rod. Then I threaded both cuts and purchased a long coupling nut to be able to adjust the pushrod length. Again, I highly recommend.

"My CJ is a 1985 with manual brakes. The donor vehicle is 1992 YJ. All you need is the booster, rear bracket and both the primary and secondary push rods. Got the parts free. Took less than an hour even while having a beer and socializing with some pals.

I left the brake lines in my master cylinder and disconnect the brake pedal from the push rod.
Unbolt the two master cylinder bolts and pull the master cylinder away from the firewall stretching the brake line coils out.
Remove the snap ring from the back to pull the push rod out. A bit of brake fluid came out. Remove the small snap ring from the push rod and the push rod can be pulled from the spacer. Put the spacer and snap ring back into the master.
After making measurements of the original push rod and the secondary push rod from the booster I found the YJ secondary push rod to be about .04" shorter. Lucky thing is the YJ's is adjustable. Unscrew it one turn and it is about right.
The primary push rod (brake pedal to booster) was about .220" too short. No big deal, I put it in like it was. Turned the primary push rod around 180 degrees and put it in the jeep. Bolt to firewall, no drilling. Just remove the four bolts that are meant for power and use them. Connect the brake pedal. The master cylinder bolt holes are a bit tight to mount to the YJ booster. You may want to elongate them or you could do what I did. Use the impact gun and force fit the bastard.
Get your friend in the jeep and have him/her push the brake pedal down very slowly while you watch in the master cylinder for air bubbles. (Recall that fluid had leaked out the back when the original push rod was being removed.) Have them release the pedal just as slow. Repeat a few more times. I only had a few bubbles the first push and release then no more came out.
Run the vacuum line to the intake manifold. I put mine into a 3/8" port found under the carburetor in the carb spacer.
Your brake lights are on because the new primary push rod is almost a 1/4" shorter. Just bend (by hand) the brake light trigger switch tab at the top of the brake pedal.
Turn the key, get going and stop. Wee, that was cool. Good luck."

 

[Tin Medic]

Good, sounds easy. I went with a TJ setup as it kept the MC lines on the same side. Should be doing the swap this next weekend.