1995 GMC Yukon Owner's Manual - Page 231

Trailer Brakes If your trailer weighs morethan 1,000 pounds (450 kg) loaded, then it needs its own brakes - and they must be adequate. Be sure to read and follow the and instructions for the trailer brakes so you'll be able to install, adjust maintain them properly. Your trailer brake systemcan tap into your vehicle's hydraulic brake system, but consider the following: 0 Don't tap into your vehicle's brake system if the trailer's brake system ~ fluid from your vehicle's will use more than 0.02 cubic inch ( 0 . 3 ~of ) master cylinder. If it does,both braking systems won't work well. You could even loseyour brakes. Will the trailer brake parts take 3,000 psi (20 650 kPa) of pressure? If not, the trailer brake system must not be used with your vehicle. 0 If everything checks out this far, make the brake tap at the port on the master cylinder that sends the fluid to the rear brakes. But don't use copper tubing for this. If you do, it will bend and finally break off. Use steel brake tubing. Driving with a Trailer 4-43