Wacker RD11A, RD11V Roller Repair Manual (incl. Wiring)

Check the 20A main fuse at the electrical panel first, and replace it if blown. Then verify the neutral switch is making good contact; test continuity per page 94. If the fuse is intact, trace the starter solenoid circuit: measure voltage at both solenoid terminals and confirm a clean chassis ground, referencing page 97. A failed crank relay or faulty key switch (test switch continuity at page 96) are the next suspects. Restore all wiring connections before condemning the solenoid.

Inspect the exciter solenoid first: check solenoid movement, measure coil resistance, and verify supply voltage per page 95. If the solenoid is firing, move to the hydraulic side. The vibration system troubleshooting chart on page 106 walks you through exciter pump flow, frequency, and motor/bearing checks. Listen for any squelching or grinding from the front drum before teardown; worn exciter gears or a failed bearing inside the drum assembly (pages 63-67) are the most common mechanical culprits. Pull the drum only after ruling out the solenoid and hydraulic pressure.

Confirm the engine is reaching 3200 rpm under load; a throttle cable that isn't fully seating will cap speed regardless of operator input. Check the operation procedure on page 19: ensure the throttle control lever is set to full throttle. If speed is still low, check the drive circuit relief valve pressure; it should be 2900 psi (20 mPa) per page 45. Low pressure points to a worn drive pump or misadjusted relief. Cross-reference the drive system troubleshooting chart on page 106 for pump and motor failure steps.

Test the anti-afterfire solenoid with the key in RUN: the plunger should extend and hold with battery voltage applied. Check wiring continuity and confirm the battery connection is clean and tight; a marginal voltage drop causes chatter. Follow the diagnostics on page 94 to test solenoid operation, wiring path, and ground. If the solenoid coil measures out of spec or the plunger sticks, replace the unit. Verify the fuel shutoff fully seats when the solenoid drops out; incomplete seating causes post-shutdown run-on.

Check hydraulic fluid level first — the system holds 5.7 U.S. gals. (21.6 liters) and low fluid causes both weak steering and cavitation. Inspect the articulated joint for physical binding or debris before touching hydraulics. The steering troubleshooting procedure on page 106 covers low hydraulic pressure, steering valve and cylinder faults, and exciter pump output. Verify the forward relief valve is holding 2900 psi (20 mPa) per page 12; a pressure drop below that indicates a leaking valve or worn pump. Clear any contamination from hydraulic lines before reassembly.

Wipe down all hydraulic lines and connections dry, then run the machine briefly and trace the wet trail to its origin. Check all manifold block fittings and relief valve seats on pages 39-45 for weeping joints. Inspect drive motor and exciter motor shaft seals at the drum assemblies (pages 63-67); these are common wear points on high-hour machines. Top the system back to 5.7 U.S. gals. (21.6 liters) and recheck after 30 minutes of operation. Any fitting you re-torque, reference the torque specifications on page 110 for correct fastener values.