The 1987 Jeep YJ is the first generation of the Jeep Wrangler, featuring a 2.5L 4-cylinder or 4.2L 6-cylinder engine, manual or automatic transmission, part-time four-wheel drive system with Dana axles, and the classic Jeep open-body design. This repair manual covers maintenance, troubleshooting, and repair procedures for all major systems including engine, transmission, drivetrain, suspension, brakes, electrical, and body components.
Key specifications for the 1987 Jeep YJ Wrangler.
| Component | Specification |
|---|---|
| Engine Options | 2.5L AMC 150 I4, 4.2L AMC 258 I6 |
| Transmission | 5-speed manual (AX-5/AX-15), 3-speed automatic (TF904) |
| Transfer Case | NP231 Command-Trac part-time 4WD |
| Front Axle | Dana 30 |
| Rear Axle | Dana 35 |
| Wheelbase | 93.4 inches |
| Fuel Capacity | 15 gallons |
| Gross Vehicle Weight | 4,000 lbs |
| Tire Size | P205/75R15 (standard) |
| Turning Diameter | 34.2 feet |
Repair and maintenance procedures for engine components.
WARNING! Always disconnect battery before working on electrical components. Allow engine to cool before opening cooling system.
Service procedures for transmission, transfer case, and axles.
CAUTION! Use proper jack stands when working underneath vehicle. Transmission fluid may be hot after operation.
Hydraulic brake system service and repair.
Front Brakes: Disc brake pad replacement, caliper service, rotor machining specifications. Rear Brakes: Drum brake shoe replacement, wheel cylinder service, adjustment procedure. Master Cylinder: Bench bleeding and installation. Brake Lines: Steel and rubber line replacement. Parking Brake: Cable adjustment and service.
Wiring diagrams and electrical component service.
Tip: Always use multimeter for electrical diagnosis. Refer to color-coded wiring diagrams.
Body panel and interior component repair.
WARNING! Use proper lifting equipment for hard top removal. Wear safety glasses when working with glass components.
Scheduled maintenance intervals and procedures.
| Service Item | Interval | Procedure |
|---|---|---|
| Oil Change | 3,000 miles | 5 quarts 10W-30, filter replacement |
| Coolant Flush | 30,000 miles | Drain, flush, refill with 50/50 mix |
| Transmission Fluid | 15,000 miles | Check level, change if discolored |
| Transfer Case Fluid | 30,000 miles | Drain and refill with Dexron II |
| Differential Fluid | 30,000 miles | Drain and refill with 80W-90 gear oil |
| Brake Fluid | 2 years | Complete system flush |
| Spark Plugs | 12,000 miles | Replace and gap to 0.035 inches |
Common problems and diagnostic procedures.
| Symptom | Possible Cause | Corrective Action |
|---|---|---|
| Engine won't start | Fuel, spark, or compression issue | Check fuel delivery, spark plugs, compression test |
| 4WD won't engage | Vacuum system or linkage | Check vacuum lines, transfer case linkage adjustment |
| Steering wander | Worn components or alignment | Inspect tie rods, drag link, perform alignment |
| Brake pull | Stuck caliper or contaminated pads | Clean and lubricate slides, replace pads |
| Electrical gremlins | Ground connections or corrosion | Clean battery terminals and chassis grounds |
Essential safety procedures for all repairs.
Always use jack stands - never work under vehicle supported only by jack. Disconnect battery before electrical work. Use proper personal protective equipment: safety glasses, gloves. Ensure proper ventilation when working with fuels and chemicals. Follow torque specifications precisely. Keep work area clean and organized.
CAUTION! Fuel system repairs require special precautions - no sparks or open flames.
Manufacturer-released updates and common fixes.
Service Support: Contact Jeep dealership for technical assistance or visit www.jeep.com for latest bulletins.