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CJ manual brakes upgrade to YJ power

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CJ manual brakes upgrade to YJ power
Hammerhead

Hammerhead

Jeeper
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Location
Ontario, Canada
Vehicle(s)
85 CJ, 95 F350 , 1993 Bronco, 01 Valkyrie, 2 sleds
Easy upgrade to power brakes. My CJ is a 1985 with manual brakes. The doner 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 disconect 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 measurments 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 basterd. 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 vacume line to the intake manifold. I put mine into a 3/8" port found under the carburator 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.
 
Sounds good to me CJ. I couldn't figgure out where the most appropriate place to put it was.

On a side note, I have acquired all the nessessary parts to convert my manual steering to power. I only need the drive belt. Will be able to figure out what size after I get arround to installing. All the parts for this job are CJ stuff so I wont bother to write it up after its done.

I took some pictures of my CJ yesterday with an old camera, my new one is not working. Put one photo in my gallery.



As you can see it looks quite different this year. Most notably the seats are out of a 2004 Mazda 3. The winch bumper I made has the shackle tabs spaced perfectly for the tow bar that is seen in one of the old pictures. The front suspention was swaped out in favor of YJ Rubicon Express SOA leaves. I am currently waiting for parts that should arrive on Tuesday to finnish up the stainless steel dash.
 
digging the seats, not crazy about the highlift location, saw a guy eat it in a car accident.
 
I like my YJ brake conversion, I got the power steering stuff off of the YJ also. I need to get the power steering done.
 
Fortunately Brockgrimes my highlift is not zip tied on. I made a bracket that is profiled to the front hinges and uses the 6 bolts that tie the hood on. The high lift is then bolted with two 3/4" head 1/2-13 bolts to the mount. If it comes off I expect it to take the tub with it. Besides, I dont crash into people. I debated for a while before locating it there. Many put theirs at the tailgate but I feel it safer to keep it up front where I can clearly see it get tangled in branches and whatnot.

If anyone wants to use the Mazda seats just be aware that short people will have their feet dangle. I did not take measurements but the seat hight is higher than it was before. I would guess at least 2".

Gper, just make sure you have the steering shaft to go with the power steering box and the pitman arm I am told has a different spline. I have not yet checked but will know for sure today.

Edit: reread your post Gper. Realized you said the power steering was off a YJ. I thought to go a similiar route, decided against it due to having too many differences and being requiered to custom make too many things. Let us know how yours goes.
 
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The one I saw was a commercially sold product for use on the hood. But you sound like you have a pretty stout setup.
 
That was great information. I am going to try to do this some time this week. I have the doner parts sitting on the YJ I am tearing appart right now.
 
Help!!!!!
I upgraded to a YJ power buster and master cylinder and bled the brake lines but the brake light stays on. I did not change to the YJ proportional valve. I disconnected the sensor on the proportional valve and the light went off. Could I still have air in the system or somthing else. I took it out for a test drive and all seems to be working good and the brakes are 100% better.
 
Per somebody somewhere that knows much more than me...

Bleed the FRONT brakes out FIRST, then bleed as normal (RR, LR, RF, LF) this allows the 'sensor' to center itself in the prop. valve.
 
I tried bleeding the front first than the rear and still no dice. I also opened the front and rear ports on the portional valve and still the light stays on, if I hit the brake petal hard the light will go out for a short time. Any ideas , valve bad? It was working before I put the power buster on and new master cylinder.
 
Did you bleed the fronts out, then start over and bleed all 4 again?
I found the reference I was thinking of today...Its in the 4wheel hardware catalog as a tech tip!
 
Gper. I've been busy lately, both work and in the garage. I can't help with YJ power steering but the CJ did require the power steering pitman arm and the coupling at the base of the steer shaft. In other words, the steering box has different input and output shaft sizes compared to the manual box.

WARNING, those of you who have the 2.5l engine will suffer a huge loss in engine power. I have heard of people running the quarter mile races with drive belt accessories disabled. Now I have hands on experiance as to why. My CJ had a hard time to maintain highway speeds around 65mph ( with my 31" bias mud terraines). After installing power steering I have difficulty getting the darn thing into 4th gear. 50 to 55mph is hard to do. When the road has a down grade I am able to use 4th. Yup, now I need to upgrade the engine. I have a line on a nearly free Chev. 350 that can turn 7500rpm without kabooming. It is a used oval track race engine my buddy has. I am part time pit crew helper for him so he offered up the gear. My concern is that engine will have too much power and the CJ will start to granade drivetrain parts. A HO 4l would likely be a better swap. Anybody who has hands on experiance with either of these swaps could chime in here.
 
2lostspace. I did not have to bleed my brakes the way I did my conversion. In fact, the way I did it was to avoid the bleeding operations. I only needed to do a little bit of master cylinder bleeding. It is possible your bleeding techniques are not getting you the desired results. More likely though, you have air in the master cylinder. That would cause your proportioning valve to opererate disportionaly if the air was in one side. The way most people bleed a master is in a vice with 2 hoses directing the fluid back into the resivoire. In a vice, I plug the outputs and bleed, watching for the air rising from the bottom of the resivoir. Be careful not to push too hard at first. Then mount the master and install the lines (this is where you are). Repeat the master bleeding with a helper in the vehicle. Watch for air coming from the bottom of the resivoir while your helper applies the brakes very slowly (engine off) and then release the brakes very slowly. Repeat till you see no more air. If you get brake fluid in your eye, your helper is working the pedal too fast. Have them go slow enough that you do not see a fountain. Once the master is properly bleed you may begin at the farthest wheel working to the closest wheel. Hope this helps bro.
 
Thanks for the advice I will try to blead the master cylinder after work tonight. I was reading some were that if the rear brakes are not adjusted right that might cause this type of problem. Heard anything like that??
 
Yes 2lostspace, the rear brakes will not work effectively unless the self adjusters are set correctly. They are supose to adjust themself when a vehicle is backed up and press the brake hard. Unfortunately it seems they are called selfadjusters because you must adjust them yourself. I do mine like this. Tighten the adjuster untill the drum is difficult to install and turn. Remove the drum and loosen a 1/4 turn. If the drum is wore it will have a ridge that will make it difficult to remove. You have an access hole at the back of the plate you can adjust from. Be very careful if you elect to use it to adjust because you can easily overtighten and then you will burn the shoes while driving normally. Make certain your drums are not hot after a short drive. Also, use compressed air and brake cleaner while your in there to get rid of all the contaminents.
 
2lostspace said:
Help!!!!!
I upgraded to a YJ power buster and master cylinder and bled the brake lines but the brake light stays on. I did not change to the YJ proportional valve. I disconnected the sensor on the proportional valve and the light went off. Could I still have air in the system or somthing else. I took it out for a test drive and all seems to be working good and the brakes are 100% better.
Click to expand...

If your brake light is on it is because up on the top of the brake pedal, the brake light switch is not making contact... it is because the rod lenght is shorter/longer, I forget which... look up under your dash and screw it in or out accordingly so it makes full contact... this is a very common issue.

cb
 
I read that post and thought 2lostspace was talking about a brake light on the dash. If the brake lights (plural) are on then as Certifiablejeep said the YJ push rod is almost 1/4" shorter than it should be for the CJ. You could disconect the wire to the stop light switch and thread more of it in as he said. I found it easier to bend the tab down. It will take considerable force but can be done by hand.

Buy the way, the first post in this thread clearly explained that.
 
Where to put vacuum line on chevy 305

I'm about to undertake this conversion. I picked up the booster, MC and proportional valve for my local wrecker, but I think i'll use the CJ MC and prop valve. Question is where to attach the vacuum line? I have a chevy 305 engine in there, and i'm an idiot, so I don't know where to attach the vacuum?

Please point me in the right direction, literally!

305.webp
 
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