How to Troubleshoot a 1995 Ford F150 Rear Brake Line

The braking system on your 1995 Ford F150 is a vacuum-assisted hydraulically operated system. What this means is that engine vacuum is used to help apply pressure to the input piston of the brake master cylinder, forcing hydraulic fluid through the brake lines to the wheels. Within the hydraulic system are proportioning and diverter valves. Proportioning valves split the hydraulic pressure front to rear, while diverter valves split the pressure left to right. Problems with the hydraulic system can include contaminated fluid, frozen calipers and wheel cylinders, split brake hoses or lines, leaking fittings and malfunctioning valves.

Instructions

1

Remove the brake lines from the master cylinder using line wrenches. Install master cylinder bleeding adapters and have your helper depress the pedal. You should see fluid coming out of both tubes. No fluid flow means a bad master cylinder.

2

Detach the brake line leading to the proportioning valve under that master cylinder and check for fluid flow using the above procedure. No fluid flow means a plugged brake line.

3

Jack the truck up and support it with the jack stands. Place the jack under the front frame cross member and lift it high enough to crawl under it. Place one stand under the frame behind each front wheel and lower the truck onto the stands. Place the jack under the rear axle housing and lift the truck. Place a jack stand under each side of the rear axle and lower the truck onto the stands.

4

Loosen the brake line coming from the front of the truck at the rear diverter valve on the differential. Place the drain pan under the fitting and have your helper step on the brakes. Observe the input line for brake fluid flowing. If no fluid comes out when the pedal is depressed, the most likely culprit is the proportioning valve mounted on the frame under the master cylinder. The brake line could also be plugged with contaminants.

5

Tighten the fitting at the diverter valve and loosen the brake line leading to one of the wheel cylinders. Have the helper depress the brake. Look for fluid escaping. Move to the other wheel and repeat. No fluid to one or both sides means the diverter valve is bad or the brake line is plugged. If fluid escapes from both cylinder fittings, the problem is a stuck wheel cylinder.