March 1, 2013

How to replace a log splitter flexible pump coupler

By Lyle Weischwill
How to replace a log splitter flexible pump coupler

This DIY repair guide explains how to replace the flexible pump coupler on a log splitter. The flexible pump coupler connects the engine drive shaft to the hydraulic pump. The coupler is designed to break if the hydraulic pump seizes up, protecting the engine from damage. The pump coupler deteriorates over time, causing vibration and noise when the hydraulic pump is running. If the flexible pump coupler breaks or the coupler is worn, use the manufacturer-approved replacement part to install a new one.

Use these steps to replace the flexible pump coupler on Craftsman, MTD and Troybilt log splitters.

Quick links
Tools required
Wrench set
Thin 1/2-inch wrench
Work gloves
Repair difficulty
Time required
30 minutes or less
Repair difficulty
Time required
30 minutes or less

Instructions

  1. 01.

    Disconnect the spark plug wire

    Disconnect the spark wire so there's no chance that the log splitter engine could accidentally start.

    Disconnect the spark plug wire.

    Disconnect the spark plug wire.

  2. 02.

    Remove the hydraulic pump

    Using the thin 1/2-inch wrench to keep the hex-head bolts from moving, remove the 3 flange lock nuts from the hex-head bolts that secure the pump to the flexible pump coupler shield.

    Pull the pump off of the engine.

    Tip: The thin 1/2-inch wrench fits in the small space between the heads of the hex-head bolts and the side of the engine.
    Remove the flange lock nuts.

    Remove the flange lock nuts.

    Remove the pump from the engine.

    Remove the pump from the engine.

  3. 03.

    Remove the flexible pump coupler

    Slide the coupling shield off of the hex-head bolts on the side of the engine.

    Pull the flexible pump coupler out of the coupler halves.

    Clean any residue from the broken flexible pump coupler out of the coupler halves.

    Remove the coupling shield.

    Remove the coupling shield.

    Remove the flexible coupler.

    Remove the flexible coupler.

  4. 04.

    Install the new flexible pump coupler

    Reinstall the coupling shield.

    Position the new flexible pump coupler on the pump-side coupler half.

    Slide yourself under the coupling shield so you can guide the coupler halves together.

    Push the pump onto the hex-head bolts and guide the pump-side coupler half into the engine-side coupler half, rotating the pump-side coupler half to line up the coupler halves.

    Reinstall the 3 flange lock nuts on the hex-head bolts to secure the pump on the engine. Tighten the 3 flange lock nuts securely.

    Tip: Use the thin 1/2-inch wrench to hold the hex-head bolts stationary as you reinstall and tighten the 3 flange lock nuts on the base of the hydraulic pump.
    Reinstall the coupling shield.

    Reinstall the coupling shield.

    Reinstall the flexible coupler.

    Reinstall the flexible coupler.

    Reinstall the hydraulic pump.

    Reinstall the hydraulic pump.

    Reinstall the flange lock nuts.

    Reinstall the flange lock nuts.

  5. 05.

    Reconnect the spark plug wire

    Attach the spark plug wire and make sure the log splitter engine works properly.

    Reconnect the spark plug.

    Reconnect the spark plug.

  6. 06.

    Test the hydraulic pump operation

    Start the log splitter and test the operation of the hydraulic pump and the flexible coupler.

Warning: Undertaking repairs to appliances can be hazardous. Use the proper tools and safety equipment noted in the guide and follow all instructions. Do not proceed until you are confident that you understand all of the steps and are capable of completing the repair. Some repairs should only be performed by a qualified technician.

Symptoms common to all log splitters

Choose a symptom to see related log splitter repairs.

Main causes: broken pump coupler, clogged hydraulic fluid filter, bad hydraulic control valve, broken hydraulic pump, bad hydraulic cylinder
Main cause: worn hydraulic valve seals around the actuator rod
Main cause: worn hydraulic pump seals
Main causes: dirty carburetor, stale fuel, bad spark plug, broken recoil starter
Main cause: worn hydraulic cylinder seals
Main causes: dirty carburetor, bad spark plug, clogged air filter, stale fuel
Main causes: leaky head gasket, damaged sump gasket, leaky oil drain plug, damaged fuel line, bad carburetor seals

Repair guides common to all log splitters

These step-by-step repair guides will help you safely fix what’s broken on your log splitter.

March 1, 2013
By Lyle Weischwill
How to replace a log splitter recoil starter

The recoil starter spins the engine on the log splitter when you pull the starter rope, and the rope retracts when released. If the recoil starter assembly is broken, follow the steps in this repair guide to replace it.

Repair difficulty
Time required
 15 minutes or less
March 1, 2013
By Lyle Weischwill
How to replace a log splitter carburetor

The carburetor mixes air and gas before the fuel mix goes to the engine. If the engine won't start and the spark plug is getting spark, the carburetor is likely the problem.

Repair difficulty
Time required
 30 minutes or less
March 1, 2013
By Lyle Weischwill
How to replace a log splitter fuel line

The fuel line carries the fuel supply from the gas tank to the carburetor. If the fuel line is cracked and leaking, replace it.

Repair difficulty
Time required
 30 minutes or less

Articles and videos common to all log splitters

Use the advice and tips in these articles to get the most out of your log splitter.

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Learn more about your log splitter with these frequently asked questions.