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1951 Willys Jeep CJ 3A Brake Conversion - Swap To Stop

Rear View
Sean P. Holman | Writer
Posted December 1, 2008

Part 5: 11-Inch Brake Conversion

The original hydraulic, non-powered brakes have never been a strong point of the flatfender Jeep. They were mainly intended for low-speed use, so the designers of the flatfenders could never have envisioned modern roads and highway speeds. After adding the weight of springs, a spare-tire carrier, and a front winch, we quickly realized on our pre-Moab test run in Ocotillo Wells, that if the stock 9-inch brakes couldn't hold our Willys on mild inclines, it certainly wouldn't hold the Jeep on the steep fins of Hell's Revenge.

There are several different ways to upgrade brakes on a flatfender, but we decided to go with one of the easiest and most popular conversions-the 11-inch drum-brake swap. These brakes were sourced off of '62-'72 Wagoneers and '72-'75 CJs, and when compared to the stock 9x1.75, the 11x2 gives much more surface area (22 vs. 15.75 square inches), has bigger slave cylinders, are nearly a bolt-on affair, and have the added benefit of self-adjusting. They can also be used with the factory master cylinder.

Here you can see the difference in size between the factory 9-inch drum and the new 11-inch drum.

After deciding to go with the 11-inchers we quickly discovered what used to be a plentiful supply of backing plates in junkyards and four-wheel-drive shops has become scarcer-even the tooling that used to make aftermarket backing plates is now gone.

We did find that one of the few sources of these parts are the guys at R&P 4WD in Oregon. They search all across the country for original backing plates to refurbish. They provide a complete kit that is essentially ready to bolt on with powdercoated backing plates and all of the hardware installed.

Mel Wade, flattie fan and owner of Off Road Evolution in Fullerton, California, lent us his shop and expertise to get our brakes swapped for this install.


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Off Road Evolution
Fullerton, CA 92833
4WD Hardware
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