87 – 94 Jeep YJ Brake Master Cylinder Upgrade

This is for those of you who have an 87-94 Jeep Wrangler and want a little more brake power for hard wheeling. Don’t bother spending a lot of money on custom built or high performance master cylinders. All you really need is one for an 85 Ford E-350.

The master cylinder off of an E-350 is rated for 1 ton use. That means it will stop your YJ with ease. This is especially beneficial if you have over sized tires. A friend of mine in Louisiana did this upgrade to his 91. He says that he barely has to touch the brake pedal on the street, and when wheeling it is a breeze stopping on steep inclines. This upgrade is also beneficial if you tow a trailer with your jeep. It will give you more positive braking force when you have a heavier than normal load on your Jeep.

The only thing that you need to do for this upgrade is to bore the mounting holes on the new master cylinder. This can be done easily with a die grinder and a carbide burr, or simply find out the size of the mounting studs on the booster and drill the holes to appropriate size.

While we’re on the topic of YJ brake upgrades, another good one for your 87-94 is a 95 power brake booster. In 95 Jeep went to a dual diaphragm booster, the same as I mentioned for the XJ Cherokees in the “Jeep Cherokee Bendix 9 ABS Upgrade” article. The dual diaphragm booster with the 1 ton, E-350 master cylinder will make a world of difference in your braking abilities both on and off road.


87 – 94 Jeep YJ Brake Master Cylinder Upgrade — 2 Comments

  1. It won’t let me post a comment under the Bendix 9 upgrade part and I had a few questions about the swap. First, what do I do with the wiring that going to the Bendix system? Do I need to do anything with any of the fuses or relays? Second, where do I get the vacuum for the new system?

Leave a Reply

Your email address will not be published. Required fields are marked *


You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>