1951 Willys Jeep CJ 3A 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.

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

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.

1. With the vehicle jacked up, the factory wheels and tires were removed and the dust cap popped off.
1. With the vehicle jacked up, the factory wheels and tires were removed and the dust cap
2. Sometimes when you don't have the right puller (and we checked several local tool shops) you have to become resourceful. We found a set of steel wheel spacers in the shop that allowed us to use a puller we had to pull the axles.
2. Sometimes when you don't have the right puller (and we checked several local tool shops
3. Next, the axle nut and drum were removed from the brake assembly.

4. We then removed the hard line from the wheel cylinder.
5. Before the stock backing plate can be removed, the grease protector needs to be unbolted.
5. Before the stock backing plate can be removed, the grease protector needs to be unbolte
6. With an easy tug, the stock 9-inch brake backing plate is pulled free of the Dana 41.

7. The new brakes come with a backing plate that is preassembled and ready to be bolted on.
7. The new brakes come with a backing plate that is preassembled and ready to be bolted on
8. The grease retainer was replaced and we bolted the new backing plate into place and then torqued the bolts down.
8. The grease retainer was replaced and we bolted the new backing plate into place and the
9. After reshaping the hard line, we were able to connect it to the new wheel cylinder.

10. Before we could button up the rear brakes, the wheel studs had to be pressed out of the old drums and repressed into the wheel hub.
10. Before we could button up the rear brakes, the wheel studs had to be pressed out of th
11. Next, the hub was rejoined to the axleshaft.
12. With the rear brakes swapped out, we adjusted the linings and installed the new drums.

13. Once the wheels and tires were back on, we lowered the Colonel and torqued down the axle nuts.
13. Once the wheels and tires were back on, we lowered the Colonel and torqued down the ax
14. The front drum installation is similar to the rear installation, including the studs needing to be removed and pressed into the hub.
14. The front drum installation is similar to the rear installation, including the studs n
15. Here you can see the new front brake hoses that come preinstalled by R&P 4WD.

16. Lastly, we installed a new master cylinder from 4WD Hardware and flushed the system with fresh brake fluid before bleeding it.
16. Lastly, we installed a new master cylinder from 4WD Hardware and flushed the system wi

How It Works

We love our new 11-inch brakes. What a difference! The Colonel can now be held with one foot on an incline and there is much less effort in regular driving to get the old Jeep stopped. We now see why this was such a popular conversion back in the day. We had a lot of fun swapping out the brakes, something that could be done in a weekend if you are taking your time. Emergency braking is now more secure and we can actually lock up the rears if we really try hard. Pedal feel is even decent and driving the Willys on Hell's Revenge in Moab went from a frightening proposition to an enjoyable one.