The kit is incredibly complete,...
The kit is incredibly complete, down to replacement cotter pins for the ball joints, spacers, and longer bolts depending on what year Jeep you are putting the kit on.
When it came time to upgrade the brakes on our unit bearing-shod Dana 30 front axle,we didn't want to spend weeks on end scouring junkyards and websites trying to find the perfect combination of parts. This Jeep is our daily-driver and there was no way we were going to take it apart and put it back together several times. We wanted better brakes without reinventing the wheel, and we'd heard a lot about bolt-on big brake kits on the market.
Bolt-on sounded really good and after a short time we discovered American Expedition Vehicles is offering not just one, but two kits. There is a 16-inch kit and a 17-inch kit available. They are so named for the suggested rim size. The 16-inch kit bumps the rotor size up to 12 inches and the 17-inch kit bumps it to 13.2 inches. Both kits include new dual-piston calipers and new nodular iron steering knuckles. The 17-inch kit adds a new master cylinder due to the amount of brake fluid the calipers require. Both kits will fit all TJs and LJs with the Dana 30 or 44 front axle, '91-and-up XJs, MJs, and YJs, and '93-'08 Grand Cherokees.
The first thing we did was...
The first thing we did was drill a nice, big, 3/4-inch hole through our knuckle. We are running our steering over the knuckle, and as of press time, there is no over the knuckle option on this kit-so we drilled the new knuckles out and installed some inserts from Goferit Offroad so the taper would work with our steering. It would be cool to see an over the knuckle or even a high-steer option to this kit, since you are already in there.
AEV suggests the 16-inch kit for tires under 35 inches and the 17-inch kit for Jeeps with a minimum of 37-inch tires. We are running 16-inch Rubicon rims and 33-inch Goodyear Silent Armor tires on our test Comanche so we opted for the 16-inch kit. We got our kit from Northridge 4x4. Northridge is a 4x4/Jeep parts store that has good prices and customer service. They also had the 16-inch kit in stock and were able to ship it out to us that day, which we liked.
AEV claims an approximate 25-foot decrease in stopping distance from 60 mph but our factory brakes were shot. So in the interest of honest reporting, we installed a new set of Raybestos pads and Brembo rotors from 4WD Hardware for a true apples-to-apples test of 60-0 stopping distances. Mind you, the parts we used were just high-quality factory replacements. AEV also cites an approximate 2.5-hour install time, which meant we could bump our braking performance and still have time to BBQ at the end of the day. Follow along as we test all the claims and give a blow-by-blow of the installation from our driveway and our desert test track.
How's It Work?
Before the install, even with Trasborg pushing on the brake pedal, we couldn't lock the brakes up on our MJ, and our 60-0 mph average stopping distance was 170 feet. We did three sets of three stops each to test, with cool down time between tests. The third stop of each test on the stock brakes resulted in much longer stopping distances. Not counting the run to the parts store for longer studs, the install took us about three hours. After the install, we were able to lock the brakes up and stopping distances greatly decreased. It took us a while to get the hang of panic stopping due to being able to lock up the brakes. Our 60-0 mph average came down to 137 feet, with much less brake fade. We were actually able to get five very hard stops in before we saw the same brake fade as we had with the stock brakes on the third pass.
Once the stock caliper and...
Once the stock caliper and rotors are off, remove the three bolts holding the unit bearings to the factory knuckles and slide the entire assembly out. Take care not to damage any axle seals. Pop your tie rod off at this time, too. We elevated only one side of the axle at a time so we didn't lose any gear oil.
The stock rotors measure 11...
The stock rotors measure 11 inches and the rotor for the 16-inch kit is 1-inch bigger at 12 inches. Just like an engine, it is all about torque. It's easier to loosen a tight bolt with a breaker bar than a 1/4-inch-drive ratchet, and the same idea applies here. The further from the axle centerline you move your friction material, the more effective it becomes. Bigger brakes always work better, thanks to physics.
While you have the knuckle...
While you have the knuckle off, check the ball-joints and tie-rod ends for any excessive looseness and replace as needed. Also make sure to support the caliper to keep stress off the brake line. The instructions state that you might have to open up the banjo fitting, but our aftermarket stainless line bolted right up using the banjo bolts and crush washers that came with the kit.
Another fool-proof brake tweak...
Another fool-proof brake tweak is to use more pistons in the caliper. Do you use sandpaper with one finger or your whole hand? The more pistons there are, the more evenly they push on the brake pad, which means less deflection and more force directed right at the brake rotor. All that means more whoa. The stock caliper features a single 66mm piston, the 16-inch dual-piston caliper features two 48mm pistons, and the 17-inch caliper features two 54mm pistons.
You will want to make sure...
You will want to make sure you have your torque wrench on hand. The ball joints, tie rods, unit bearings, and brake caliper mount all need to be torqued to spec. Failure to do so could lead to disastrous results down the road should something work its way loose. Too tight and the result could be binding and/or stripped threads. AEV's very thorough instructions provide all the correct torque specs that are required for the job.
The instructions mention the...
The instructions mention the possible need to bend the dust shield, depending on the year of the Jeep. While this axle came out of a '99 XJ, we really have no idea what year the dust shields are from. We ended up both trimming the shield with a Dremel tool and then bending it as well. Before putting the rotor on, we test-fit the caliper to check for possible clearance issues.
Take care to keep your dirty,...
Take care to keep your dirty, greasy hands off of both the pre-loaded pads and the friction surface of the rotor. Even if you did this with white gloves on, before putting the rotor on, clean it with brake cleaner. The rotors ship with some light oil on them to keep them from rusting, and you don't want that oil to fowl up your new brake pads.
Even though we used high-quality,...
Even though we used high-quality, one-piece rotors before, the new rotor hats were still 1/10-inch thicker than the old rotors. Check that you have full engagement of your lug nuts before driving. We ended up having to replace our studs with Dorman part number 610-080 for full engagement. While there are a few alternatives, these were all we could find at our local parts stores. Have a knowledgeable counter guy take the book out and cross-reference your existing stud to find a new one. If your Jeep now runs the cheaper, thin two-piece rotors, you will see even more of a difference.
The included longer bolts...
The included longer bolts and spacers (arrow) are supposed to be for pre-'99 Jeeps according to the directions. However, we ended up having to use them even though our axle was out of a '99 Jeep. Even with a kit as complete as this, pay attention to clearances and fitments before driving. While the kit even includes ball-joint cotter pins, it doesn't include tie-rod cotter pins. Fortunately, we had some on hand. Otherwise, the instructions and hardware included in the kit are very complete and easy to follow.