Install: Finding the Right Stopping Power - Wilwood Brake Calipers
You may remember our article “44 for Life” Dana 44 (4WD June 2018) that we built for the back end of our Stinky Jeep. We took everything we had and threw it at a pedestrian Dana 44 rear axle and ended up with a bantam-weight trail beast with parts from ARB, Yukon, Jantz Engineering and TMR. As we arrived at the end of our build phase, we also saw the end of our cash flow. We needed to stop – literally. We didn’t even install proper brakes yet.
We do our best thinking in the junkyard. After a brain storming session out there with a few like-minded CJ-7 owners, we let the bloodhound in our head loose and we chased down a set of rear calipers from a mid-1990’s Nissan Altima. “Why those?” you ask. Well, they are easy to locate and have a built-in, reliable emergency brake that clamps on the rotor it rides on. That rotor for us was a Suzuki Samurai front unit, which has the same bolt pattern we were after. Perfect
With our pile of parts at home and mounting brackets cut and drilled into a 3/8” mild steel plate, it was time for a test. Initial results were less than satisfactory. After installing a Wilwood adjustable proportioning valve, our results were mediocre at best. The Jeep had amazing braking ability with the parts it had, but the massive front rotors and calipers were doing 95 percent of the work.
That was a few years ago and we have suffered lackluster braking while keeping an eye out for a solution. An unlikely source had us with a full Wilwood used brake assembly that was meant for a Shelby Cobra replica car with a Ford 9” rear axle. Some quick and dirty measurements revealed that these “leftovers” from a high-dollar build may just be the ticket for our lack of “woohhh.” We wanted to make sure this was going to make a difference, so we made a call to Wilwood’s tech line and asked some questions.
Even though we didn’t purchase the brakes from Wilwood, and didn’t mention that we had some of their components, they were extremely helpful in getting us back to braking efficiently. It turned out our main issue was not with our master cylinder, brake bias adjuster or anything else, it was the size of the pistons in the rear calipers. According to Wilwood, we had 83 percent of the braking power going to the front and 17 percent to the rear – pathetic.
With the disc brake setup, Wilwood prefers a 1:1 ratio of front-to-rear braking power and then use a bias adjuster to dial in the braking to ensure maximum performance. This calculation involves everything from rotor diameter, effective brake pad area, and even the coefficient friction (grippy-ness) of the pads.
The new-to-us Dynalite calipers were measured out and the four-piston units were an almost perfect match to the massive single piston units used in the front. However, it wasn’t all good news. The rotors that came with the kit were designed with a 4.5” or 5” five-bolt pattern and our old CJ wears a 5.5” bolt pattern so a little measuring and machining were required. Another possible headache was making sure that the backing plates and the caliper mounting brackets would be in proper alignment. Lucky for us, only some small spacers were required. If this hadn’t worked out, Wilwood carries plenty of different brackets and mounting adapters for just about any common axle setup. We lucked out, but were in good hands if everything went to hell.
With the decision made to take one more swing at getting properly working rear brakes, we started the planning process of bolting the Wilwood brackets, Dynalite calipers and two-piece rotors in place. After some time on a milling machine, our rotors were all set to go after just a few hours work.
This really isn’t a ‘drill press and tape measure’ type of job. If you find yourself having to modify brake rotors or any component where proper runout and balance is needed, go to your local machine shop. We also decided to get some new brake pads and a seal kit in case we had to rebuild the calipers. Fortunately, Summit Racing had most of the parts we needed.
Once all the parts were in, we ditched our junkyard brake setup from the old CJ-7 and bolted in the Wilwood binders. We were shocked at how easily this set-up bolted on given it was not originally designed for this application. Onto getting fluid to the new stoppers. While fully expecting to need custom brake lines made, we happened to have a set of -3AN brake lines and adapter fitting we got out of an old Skyjacker lift kit. Who says “hoarding doesn’t pay?”
A brake bleeding with fresh DOT4 fluid later, we were ready to test the new setup. After a few slow runs up and down the street and adjusting the brake bias adjuster, we could lock the massive 37” tires up on all four corners - finally.
What’s the moral of the story? Listen to your instincts if you feel something isn’t right. We didn’t feel 100 percent comfortable with our braking setup, even though we only used the rig on the trails. Now that we have newfound confidence in our ability to stop in an emergency, we started street driving the old rig once again.
For those of you who are thinking “what about the emergency brake?” Well, stay tuned. Wilwood has a perfect solution for that problem as well, which we’ll tell you about in an upcoming issue.
Installing Wilwood Brakes on Our Good Ol' Stinky Jeep
1. Main Components for the Wilwood Brakes Installation
Along with some anodized aluminum brackets, these are the main components we needed to get this project rolling (er, stopping).
2. Slight Modification to Center Hole & Bolt Patter
We are lucky enough to have access to a milling machine so some mild modification to the center hole opening and bolt pattern were not a problem. Safety third, right?
3. Plenty of Wiggle Room for Rotor & Wilwood Brake Caliper
The new rotor and caliper have plenty of wiggle room. They look like they were made to be here. The Jeep wheels are “Lug Centric” meaning the lug nuts center the wheel, but the rotors are “Hub Centric”. This means that the center opening of the rotor is what gets it centered as it indexes the axle shaft. A little wiggle room is “OK”, but the closer the better.
4.All Brackets Bolted Up With Ease
The axle flange on this old scout axle is the same as the “New Big Ford” flange. Wilwood has specs on many popular flanges on its website. All of our brackets bolted up without any modification.
5. Solid Mount & Centered Perfectly
Unlike typical production single piston vehicles, the caliper is solidly mounted and must be centered across the rotor. We had to use a few spacers and very thin washers to get everything perfectly aligned.
6. Brake Line Adapters!!!
For anyone who has shopped for brake line adapters, you know they can be hard to find, and priced astronomically. We keep any adapters we come across under lock and key.
7. Compliant Brake Lines
In the “CYA” (cover yer aXX) world we live in, we were pleased to see that the Skyjacker brake lines were DOT compliant.
8. Ready to Roll!
Lines attached, bolts checked, fluid bled, it’s test and adjustment time.