|Author: Jim Brink December 2000||
Brake system upgrades, namely converting the rear drum system to disc, are popular modifications for owners of Toyota pick-ups and 4Runners. Many rear disc brake kits available from the aftermarket utilize the popular General Motors floating front disc brake caliper found on many late-model General Motors sedans.
These calipers are inexpensive to purchase, are easy to service and rebuild, and can be acquired at nearly any automotive parts store across the country. The drawback to using this particular caliper on rear axle applications is the lack of a parking brake built in to the caliper. Once a Toyota rear drum system is swapped over in favor of a rear disc kit using these calipers, the stock parking brake system is eliminated. There are no provisions to adapt a parking brake unless calipers from a GM rear disc application are installed. While installing calipers from a rear disc system is indeed possible, connecting the parking brake mechanism to the stock Toyota cable is not so easy.
|Parking Brake Assembly.|
|Parking Brake Kit as Shipped from All Pro Off-Road.|
All Pro Off-Road has addressed this concern by offering a parking brake that is transfer case mounted. Basically, this parking brake operates off of the transfer cases output, or the driveshaft. This brake operates in a similar manner as those found on early Toyota Land Cruisers. All Pro's version differs in that it does away with the trouble-prone brake drum and in its place is a disc brake rotor and caliper. This parking brake also mounts to the output flange of the transfer case which almost eliminates the chances of the brake lining being contaminated by a leaking transfer case seal. The older Land Cruiser type drum system was prone to leakage and led to ineffective operation. As shipped, All Pro's parking brake kit comes assembled with the mounting bracket, actuating arm, caliper, rotor, and all necessary hardware. All steel parts associated with the mounting bracketry are powder coated black. Our example was nicely finished and all of the parts appeared to be professionally cut or machined. The caliper, a mechanical agricultural type, appeared to be a high-quality unit. At this time, applications are available only for 4-cylinder transfer cases.
We installed All Pro's parking brake kit on our 1986 standard bed 4WD truck. The installation of this kit on a shortbed truck or 4Runner is very straightforward. On X-Tra Cab and long bed trucks, a second front-half section of the parking brake cable needs to be purchased. Depending on the customer's style of rear driveline, All Pro offers two different brake rotors: A style to fit U-joint outputs and one to fit CV-type outputs.
|Transfer Output Flange with Dust Deflector Removed.|
Installation of the parking brake was very easy. First, remove the four driveshaft bolts at the transfer case and set the driveshaft aside. Remove the 30MM hex nut at the transfer case rear output flange. Remove the flange from the transfer case and take it over to the bench. Remove the metal dust deflector from the flange. We clamped the flange in a vise and used a chisel to separate the flange from the deflector. With the deflector off, install the disc rotor onto the flange and then press the deflector back on. Currently, our trucks rear driveshaft uses a standard u-joint. In the future, we plan to add a CV-type joint. We opted to initially request the CV-style disc from All Pro. Once received, we CAREFULLY re-drilled the disc to fit our u-joint style shaft.
|Disc installed onto Flange.|
Next, reinstall the flange/disc assemblies back onto the transfer case output shaft. Torque the 30MM hex nut to 90ft. -lbs. and re-stake the nut. Do not install the driveshaft at this point, as it will interfere with the rest of the install of the parking brake.
Now, the mounting bracket can be installed to the back of the transfer case with the supplied hardware. All Pro provides new grade 8.8 mounting hardware including flat and lock washers. This is a very easy step; the only real trick being that the caliper needs to be slipped over the disc. This is where leaving the driveshaft off helps. Once the brake assembly is mounted and the bolts torqued, the driveshaft can be installed with the original nuts and lockwashers and the new bolts supplied by All Pro. Torque these bolts to 54 ft-lbs.
The next step is installation of the parking brake cable to the All Pro unit and adjustment of the actuating arm. This is where I ran into a small problem. The clevis pin on my truck was too short to work with All Pros actuating arm. A quick trip to the parts store for a universal clevis pin solved this problem. Adjustment is a simple process as the caliper is attached to the actuating arm by a threaded rod. A few twists of the rod and a snugging of the jam nuts were all that was needed. For further adjustment, two holes are drilled in the actuating arm for the adjustment rod, giving the installer a bit more flexibility depending on the truck type (single or dual case and wheelbase variety).
|Complete Contents of Kit.|
The effectiveness of the All Pro parking brake was obvious from its first use. Once applied, the vehicle rolled slightly forward as the driveline slop was taken up. After that, the brake held firmly on a steep downhill bias. The throw of the parking brake handle was significantly shorter with this setup - Only a few clicks were needed to set the brake, as opposed to the older system. The only negative comment we had about the operation of the All Pro brake was the parking brake handles release. We think this may be a problem unique to our truck, as the parking brake cable is original. In our opinion, this should not reflect negatively on the product. We plan to replace the almost 15 year old cable very soon.
|Parking Brake Installed on Vehicle.|
Aside from the obvious advantages of the transfer case mounted parking brake, such as the ability to easily adapt rear disc brakes, there are also a few side benefits. One, benefit is the elimination of many moving parts associated with the stock parking brake mechanism. Secondly, the lack of possible contamination of the drum style system by gear oil, water, rocks, and debris. While these items may not be significant to some, and the failure rate low, any time moving parts can be removed, the chances of a failure decrease.
Having a good, working parking brake on the trail is important. In fact, it is even mandatory on certain sanctioned club runs. All Pro Off-Road offers a viable solution to those looking for not only an alternative way to add a parking brake after a disc conversion, but also an effective replacement to the factory equipment.
At this time, I have not found any disadvantages to using this type of system as a parking brake. No components of the All Pro parking brake hang down below the transfer case or seem to be vulnerable to trail damage. Only time will tell how this system works in the long run. I'm very optimistic though, as All Pro Off-Road seems very dedicated to supporting Toyota enthusiasts and therefore, parts and service of their products should not be a concern.