Better Front Brakes

[Duner]

Don't remember it this topic has been thoroughly covered before.

 

Now that 33x12.50's are mounted is there a swappable large set of front brakes available for the D30 axle? I'm about ready to try the slotted rotors and heavy duty pads. I did gain back some noticeable brake stopping power when I switched to the braided stainless lines but I would like to have more. The rear brakes are the large D44 drums, I think 10x2-3/4" shoes.

[Pete M]

What about swapping in a better master?

 

http://madxj.com/MADXJ/technical/techni ... pgrade.htm

[Duner]

I'm all for a larger master cylinder as I understand hydraulic systems are about volume and pressure. I'm not sure what benefit the larger booster would have except maybe reducing the human effort in the equation I don't think the booster can actually apply more pressure but maybe I'm wrong. Second I did not really want to change the booster as the current one is only about 10 months old. (new booster, new master, new wheel cylinders and drums for rear, new stainless lines) I'm only lacking what to do about front calipers and rotors. I know I need one rotor now but again looking for a better replacement than stock and don't mind the low cost junkyard parts.

[CEThomas]

New pads and rotors are only part of the fix. Larger rotors and pads is the way to go. Have never looked at the ZJ's to see if they are larger or would be an easy fit/fix. A few years ago on my bike I had went new pads and SS lines with little gain, but when I got some new brackets made and moved the calipers so I could use a 20mm larger rotor and pads it made a BIG difference.

 

But, a swap of ZJ parts is one thing. If you do not know brake systems or know an engineer DO NOT just start bolting on or making different parts.

 

Charles

[Eagle]

ZJ brakes are the same as XJ. For larger rotors and calipers you need WJ brakes, but that involves significant changes to the front end, as well as running 16" rims.

 

For most of us, semi-metallic or carbon fiber or ceramic pads coupled with the upgrade to a two-stage vacuum booster will provide significant improvements.

[feerocknok]

ZJ brakes are the same as XJ. For larger rotors and calipers you need WJ brakes, but that invloves significant changes to the front end, as well as running 16" rims.

 

For most of us, semi-metallic or carbon fiber or ceramic pads coupled with the upgrade to a two-stage vacuum booster will provide significant improvements.

WJs are dual piston, right?

[carnuck]

I upgraded the rear brakes in my '87 MJ 2 ways. I replaced the wheel cylinders with ones from an AMC Eagle (same year) which are larger bore and I bypassed the load level valve and went to 1 line. Now I stop the same whether fully loaded or not.

Later I plan to put in an adjustable valve between the front and back and put the '93 ZJ front brakes on with discs in the rear.

[Eagle]

WJs are dual piston, right?

I don't remember, and I don't really like to think about it. I bought a new WJ once. Biggest automotive mistake I ever made. It was a complete, total POS and DaimlerChrysler eventually bought it back to stop me from going lemon law with it.

 

When they worked, the brakes stopped pretty well. The problem was, the front rotors warped if you looked at 'em cross-eyed or spoke unkindly within their hearing. I owned the thing about 9 months. Within that period, the dealership cut the original rotors once to elimiate warping, replaced the rotors, cut the replacements to eliminate warping, and when it departed my ownership the re-cut replacement rotors were warped again.

 

I'm much happier with the old-fashioned, non-warping brakes on my '88 MJ and XJ. I do hope someday to make the conversion to a two-stage booster, but despite the supposed advantages you'll never find me doing the WJ conversion. There are other, less expensive and less complicated ways to improve the stock brakes.

[Duner]

Went to the EBC brakes web site and found a few answers apparently you can now buy the pads and rotors OTC at O'reilly Auto parts. I will check the price of the 6000 and 7000 series brake pads for 4x4 & Suv's on Sat. They were at least kind enough to note that for normal and mild offroad use (i.e. not running the baja or jeepspeed) normal rotors that are not drilled or slotted would yeild the best results. So don't wast the bucks on the fancy rotors unless your hot lapping your MJ. Simple physics more surface area more agressive pad = more stopping power as long as the rest of the system is working properly.

[purplexj]

You can get the slotted brake kit from SSBC . Work great on my XJ and just involves swapping parts. I think it was $200 del to my door. I already had there rear kit, 7 years old now, and the 95 up booster. The dual booster made the biggest diference and it cost me $0 from my friends junk , sorry, wrecking yard.

[Eagle]

The dual booster made the biggest diference and it cost me $0 from my friends junk , sorry, wrecking yard.

What vehicle did you get the booster out of, and how much custom fitting did you have to do to make it work?

[purplexj]

It was a 94 or 95 Xj. Fit right in w/no changes. Mine is a 92. But I think to make it easier if you have a renix model you can get the pedals and brake switch and clip out the connector to the sw out of the donor Xj. The newer models, I think 97 up have a dif push rod. Junk yards will tell you it doesn't fit and no price diff between the one you have and the dual. I didn't take any pics of the install, sorry. Make sure to get the manifold off in one piece with out cutting the lines and some have a bit plastic spacer between the fire wall and booster, you need it too. Doesn't take long to remove or replace. Connecting brake light sw and getting your wife to help bleed brakes after a sandwich will take longer.