I don't know about "upgrade" kits. The only thing I would consider is an optional factory system, but that will be part of a complete package. Why do you feel the need to upgrade? Your brakes will already lock up and skid the tires. You can't do much more than that.
This is a little related to my story about lowering cars and raising trucks. Doing that raises the center of gravity and that adversely affects braking, steering response, directional control, and handling. Lawyers and insurance investigators love to find those modifications on the other guy's vehicle after their client caused a crash. They will convince a jury that person was partially at fault because they were less able to avoid the crash, and they will be right.
The issue in your case is the front-to-rear braking balance. That was carefully designed in based on a number of factors including engine and transmission weight, optional equipment like air conditioning, larger radiator, etc. Any changes that are done must be done to the front and rear to maintain that balance.
Typically a larger front brake caliper is mounted on a different knuckle which is part of a different spindle, and may only be included in four-wheel-drive versions. You could end up looking for steering and suspension parts you never thought of just to go to bigger brake pads. Most people aren't aware of the "proportioning" valve in all brake hydraulic systems. That limits how much brake fluid pressure can go to the rear brakes to reduce rear-wheel lockup during hard braking. If that valve is not the correct one, the rear brakes might not do their share of the stopping or they might allow easy rear-wheel lockup and loss of control. Anyone at the dealer's parts department can look up parts part numbers, and based on that, tell you what is the same and what is different between the two systems. Typically they can't tell you why some parts are different.
Normally I would say to forget modifying the design that has been perfected, sell the vehicle, and buy exactly what you want. In this case I understand you probably had it outfitted already with hand controls and a ramp, so that advice isn't practical. That brings me back to my question about why you think an upgrade is needed. If the vehicle is designed to carry four people, it is capable of carrying at least 800 pounds. The brake system is designed to handle that much weight too. If pushing the brake lever is too hard or it has to be pushed too far, that should be addressed by the equipment installer or company that designed the controls. Larger brakes won't change those things.
Tuesday, October 14th, 2014 AT 9:14 PM