YJ booster/mc brake upgrade on a CJ?

[rumblephish]

So now I'm contemplating what to do about the CJ's poor braking performance, especially with over size tires. I don't want to drop a lot of cash on this because my CJ fund is running low. I started to think about the CJ's single diaphragm booster and the short push rod it has and I thought "Hmmm, maybe look at a dual diaphragm booster with a longer rod". So while I'm perusing the internet for inspiration I came across a universal 8" dual diaphragm kit that is exactly what I'm looking for! But it's too pricey $250 is more than I have to do this with. I already blew $100 on stainless steel extended brake lines from my local Jeep shop (I like to give them some business even though they are more expensive than the internet). About $200 is all I had and now I'm down to just about $100 to do this.

So I continued on my quest.

Then I came across an interesting website that showed a guy who took a booster/mc setup out of YJ (dual diaphragm) and installed it in his CJ. As I continued to read it stated that the DD booster/mc from the YJ gave much more pedal power and feel and he was also able to use the proportioning valve from the CJ. It looked to be a very simple "plug and play" swap. All of this for the cost of some parts procured from the local Pick'n'Pull and a few fittings from the local Napa store.

I did a quick search here and found nothing on this (granted, it was a VERY quick search). So my question is, has anyone tried this? Know someone who has? Pro's and con's?

 

[Sasquach]

I bought a complete system from Classic Performance products and it works like it should and was very reasonable. 2 thumbs up!

 

[mylittlecj5]

I bought a single diaphragm booster and M/C from a '95 (?) YJ off Ebay for $50. Just had to drill the firewall for the booster to mount, and now I'm working on building new hard lines to adapt it. Not exactly plug and play, but I hope it works!

 

[Trapshooter]

Here is a link to a site that has some great info on the YJ booster conversion. I found this some time ago and saved the page. Haven't done the mod myself but this was some of the best info I found at the time.

YJ Brake Booster Upgrade

Good Luck.......

 

[Shazam]

I bought a complete system from Classic Performance products and it works like it should and was very reasonable. 2 thumbs up!

Sasquatch, Interesting post - I'm needing the same thing for my CJ5 . Can you please post a link or more info as to what you purchased? Also, was it an easy install? Many thanks.

 

[79Jeep5]

I did this upgrade and i dont like it. I have no brake pedal. I got the parts off of a 94 yj, single diaphram booster. I bled everything and adjusted all the brakes. My brake pedal has about 3-4 inches of travel once i get past that point its like im slamming on the brakes. Just doesnt feel right to me.

 

[BrockGrimes]

Go with a a Dual Diaphram setup.
It's basically bolt on.
The biggest issue with it is adjusting or lengthening the rod going to the brake pedal.
Pretty simple mod and there are lots of links out there. I'll post up if I get on my home computer.
I've heard you can use dakota's, XJ's and s-10's for booster sources.

There is also Hydroboost you can snag of a chevy astro van.

http://www.4x4wire.com/jeep/tech/brakes/
http://cjoffroad.com/forums/topic.asp?TOPIC_ID=15722
http://www.4x4wire.com/jeep/tech/brakes/yjmc/

 

[Sasquach]

Sasquatch, Interesting post - I'm needing the same thing for my CJ5 . Can you please post a link or more info as to what you purchased? Also, was it an easy install? Many thanks.

I actually got mine from Classic Performance in an Ebay auction and paid some rediculous price around $170 for the firewall/booster bracket, rod, dual diaphram vacumm booster, master cylinder and proportioning valve. It bolted right in and works perfect, only glitch I can say was the duel diaphram is only 1/4" from air cleaner housing but so far no prob.
Their reg. price is still under $300 for the system as i recall so give the a look. Classicperform.com

 

[rumblephish]

I actually got mine from Classic Performance in an Ebay auction and paid some rediculous price around $170 for the firewall/booster bracket, rod, dual diaphram vacumm booster, master cylinder and proportioning valve. It bolted right in and works perfect, only glitch I can say was the duel diaphram is only 1/4" from air cleaner housing but so far no prob.
Their reg. price is still under $300 for the system as i recall so give the a look. Classicperform.com

Hey! That's basically the same set up that I got! I got it from PerformanceOnline through eBay. $170 for the bracket, DD 8" booster and MC. I didn't get the proportioning valve because I thought mine was o.k.. It wasn't (leaking) so I just ordered on from Carolina Customs through eBay for $55. Not as good as your deal but still a great deal. I picked up SS lines last week and I'll be installing everything this coming weekend. I'm glad to hear you're happy with the mod. Stock CJ brakes suck! Even when their power brakes!

I did this upgrade and i dont like it. I have no brake pedal. I got the parts off of a 94 yj, single diaphram booster. I bled everything and adjusted all the brakes. My brake pedal has about 3-4 inches of travel once i get past that point its like im slamming on the brakes. Just doesnt feel right to me.

Maybe you need to lengthen your rod (please, refrain from the obvious jokes ).

Seriously though, it sounds exactly like your brake push rod is too short now.

 

[nitor]

I did this. It was pretty much a bolt-in. It was a great improvement over the manual brakes that were on my CJ. I just had to change the fittings going into the MC. I used the same proportioning valve and lines. I think I may have had to drill holes, I don't remember. Then I bled the brakes and I was good to go. The worst part was changing the fitting on the lines