YJ brake upgrade?

[vwtipeii]

Hi everyone, I took my YJ out this weekend and had a hard time staying put with just my breaks on a few inclines. Not fun with a manual. That being said, I am looking to upgrade my breaking system. I currently have a rear disc conversion from a early 90's mustang. I am running 35" SS TSL Radials on 15" outlaw II rims. I also have a "lever lock" that is supposed to hydrolically lock all four wheels whenever I use it... It flat out has never really worked. My mechanic is not really even sure what to do

Any thoughts or ideas are greatly apprecaited.

Thanks,
B

[th3_d0c]

What year YJ? Have you upgraded to the 1995 master cylinder and booster? It is significantly bigger then pre-'95 YJs.

The conversion is relatively simple-ish.
Get the booster/master
Remove yours.
The 1995 booster fits perfectly into the old mount location
Buy a bunch of converters to convert your American fittings to the Metric fittings on the 1995 master.

[6spdYJ]

You can also use a double flaring tool to swap the necssary fittings to fit the M/C on the ends of the original tubes. You need to find out what end isn't grabbing. Try a rapid stop on gravel from about 10 - 15 mph. Try to lock them up and see which one doesn't. Also, your M/C could be wearing out. There is also a formula to figure out if your wheel pistons match your master to get the right pressure applied. Better yet, ask Jonah to walk you through a hydroboost swap.

[vwtipeii]

Thanks for the replies gents. The Jeep is a 94 YJ. I did find something that discussed swapping out to a MC of a 78 mercury marquis w hydroboost is a good swap: http://www.4x4wire.com/jeep/tech/brakes/yjmc/.

I am not sure which end is not grabbing.. it generally feels quite equal but I will work with my mech and see if we can isolate either the front or the rear. I haven't see any complete after market kits. I am eventually going to go to a Ford 8.8 so I don't want to do "too much" to the current rear assembly especially since I already paid for it as an "upgrade".

Thanks again for your thoughts and ideas. I don't mind taking the Jeep to a specialist if you know of one in the LA area.

Brett

[Old Fart]

Better yet, ask Jonah to walk you through a hydroboost swap.

Best advice I could have given. I messed around on my 94 with the Marquis MC, Corvette MC, "here's the hot tip from Pirate MC"...gave a whole milk crate of that stuff away after I went to Hydroboost.

Mine had CJ discs on the front axle, Dodge discs on the rear - and stomping on the pedal put you right into the dash

[6spdYJ]

I'm running the 78 Marquis with Miata rear calipers. The pedal feel is awesome, but my piston diameters are backwards.

[jonah]

If you are going to do anything, do the hydroboost, it is worth it. Now when I drive my passat with a perfectly good vacuum boost I think, "these brakes are lame!" I have to push so hard...

I think a lot of guys here have had success with Vanco:

http://www.vancopbs.com/

There is another guy who puts together kits here:
http://www.ifsja.org/forums/vb/showthread.php?t=106056

And a lot of good info here (from the same guy I think):
http://www.txfsja.org/hydroboost/faq.html

Or you can DIY with a trip to the pick a part which is what I did. You can pick up an Astro booster and master for around $70 (or go on 1/2 price day for cheaper). Then hoses, I spent about $120 or so on those. I am using an astro proportioning valve, but I would recommend getting an adjustable from wilwood. You will probably have to modify the push rod depending on your pedal set up, but it is nothing too tough. It all may seem intimidating at first, but it is really pretty simple.

If you want some help, drop me a line.

[jonah]

Oh, and the "lever lock" works by trapping the pressure created by the pedal. So usually you have to push the pedal, then turn the lever to lock it. Also, it usually only does one axle (rear typically). If you are having trouble getting enough pressure with the manual brakes, the lock won't be effective.

[vwtipeii]

Thanks guys, i am going with the MC upgrade from the Marquis. I am going to not add the hydroboost just yet, apparently that is a bit of overkill. i just let my mechanic know... I hope to have it back and ready for the desert this weekend!

[jonah]

Is the Marquis Master still manual or is it vacuum boost? Honestly, with 35s I would at least get a vacuum booster. I messed with my manual system (wilwood dual master setup), yes it worked but when off camber, coming down a steep grade, I don't want to have to put 100 lbs on the pedal to stop that thing.

[jonah]

I was just reading up on YJ brakes since I wasn't familiar with that model. It appears that it has vacuum boost already, I thought by the way the original post was worded that it had manual brakes.

Are you sure your vacuum booster is working? If it is and you are still having trouble holding, I am not sure how much the master swap will help, but I am interested. Let us know how it goes. Good Luck!!

[NAILER341]

Take a look at the www.savvyoffroad.com Black Magic Brake pads.
I have heard good things about these. Supposed to perform even better than the EBC yellow stuff pads which are an estimated 30% better than OEM.

[Tumbleweed13]

When I had my YJ I installed a set of the EBC yellow stuff pads up front. It felt like I upgraded the entire braking system. Combined with your M/C upgrade you should stop on a dime and hold on an incline, with no problem.

[neilbyrd]

I say go with the hydro boost I have that on my jeep and 40" Iroks and can stop on a dime. I also have the line lock that you are talking about and the hydro makes it work better(more pressure).

[vwtipeii]

Thank you for all the great input. Here is the deal... the MC and booster upgrade alone did not seem to yield much better breaking. I am in the process of putting in a ford 8.8 in the rear and I am upgrading the front and rear rotors with Centric Slotted rotors. I am also putting Black Magic pads in the front. Probably generic pads in the rear. I will keep you all posted on how things are progressing in the next two weeks. Please continue to email your thoughts and ideas.

Thanks,
Brett