21/12/2021
DIY Harley Davidson Oil Pump Removal: A Comprehensive Guide
Experiencing a significant oil leak on your Harley Davidson Touring bike (1984-1998) can be a cause for concern. While often not the pump itself that fails, a faulty seal or a damaged internal gear within the oil pump assembly is a common culprit. Replacing or rebuilding your oil pump can be a more cost-effective solution than a professional job, and with a bit of patience and the right tools, you can tackle this task yourself. This guide will walk you through the process of removing your oil pump, whether you plan to repair or replace it, with a focus on efficiency and avoiding unnecessary steps.
Why Remove the Oil Pump?
The primary reason for removing the oil pump is to address issues related to oil loss or low oil pressure. A persistent leak that you can't trace to a simpler source, such as a loose drain plug or a cracked oil line, often points towards a problem within the oil pump itself. The internal components, like seals and gears, can wear out over time or become damaged by debris circulating in the engine oil. By removing the pump, you gain access to these critical parts for inspection, repair, or complete replacement. This proactive approach can prevent more serious engine damage down the line and save you money on labour costs associated with professional removal, especially if they opt to remove the exhaust system for better access.
Tools and Materials You'll Need
Fortunately, removing the oil pump on your Harley Davidson Touring model doesn't require highly specialised tools. Most of what you need can be found in a standard mechanic's toolkit. Ensure you have the following:
- 7/16" and 1/2" Box Wrench or Sockets: For removing the bolts securing the oil pump.
- Flat Head Screwdriver: Essential for loosening hose clamps and potentially for prying components gently.
- Rubber Mallet: Useful for persuading stubborn components to separate without causing damage.
- Shop Rags: Plenty of them. This job can be messy, and rags are crucial for cleaning up spills and protecting components.
- Oil Pan or Catch Basin: To collect the drained engine oil.
- Fresh Engine Oil: You'll need this to top up the engine after reassembly.
Step-by-Step Oil Pump Removal
Step 1: Drain the Engine Oil
Before you begin dismantling the oil pump, it's imperative to drain the engine oil. This minimises spillage and makes the process significantly cleaner. Locate the drain plug on the underside of your motorcycle, typically near the temperature sensor. Position your oil pan or catch basin directly beneath it. To facilitate faster draining, remove the oil filler cap first. Once the oil has completely drained, you can replace the drain plug.
Important Note: Ensure all oil is drained before proceeding to avoid unnecessary mess and potential damage to the engine if oil levels are too high during disassembly.
Step 2: Disconnect the Oil Hoses
The oil pump is connected to the oil system via two hoses, usually located at the upper portion of the pump. These hoses are secured by hose clamps. Use your flat head screwdriver to loosen these clamps. Once loosened, carefully pull the hoses away from the pump. Be prepared for some residual oil to spill out as you disconnect them; have a shop rag ready to catch any drips.
Tip: Gently twisting the hoses before pulling can help break any suction or adhesion to the pump fittings.
Step 3: Remove the Front Half of the Oil Pump
The oil pump assembly typically consists of a front and rear section. To separate these, you'll need to remove the four bolts that hold the front half to the rear portion. Use your 7/16" box wrench or socket for this. As you loosen these bolts, more oil may escape, so keep your catch basin positioned accordingly. Once the bolts are removed, you should be able to carefully separate the front half of the pump. This is a prime opportunity to inspect the gasket between the two halves. If the gasket appears cracked, brittle, or damaged, it might be the sole cause of your oil leak. In such cases, you can replace just the gasket and reassemble the pump, potentially saving yourself the cost of a new pump. While you have the pump open, it's also wise to check the internal gears for any signs of damage or debris.
Inspection Point: A damaged or worn gasket is a very common cause of oil leaks around the oil pump housing.
Step 4: Remove Internal Gears and the Rear Pump Section
With the front half of the oil pump removed, you will expose the internal gears. There are typically two gears: a larger one and a smaller one. The larger gear is usually keyed to its shaft, meaning it has a specific orientation for removal and reinstallation. To remove this larger gear, you'll need to locate and remove a snap ring that secures it in place. A flat head screwdriver is often suitable for this task. The smaller gear typically does not have a keyway and can usually be pulled straight out from within the pump housing. After removing the gears, you'll find two more 7/16" bolts that mount the entire oil pump assembly to the engine block. These bolts secure the rear section of the pump. You might need to use the rubber mallet to gently tap the pump and break the seal with the engine case. Once these bolts are removed, the oil pump should come free. Upon removing the pump from the engine, you'll likely see two more gears on the backside of the pump, which are driven by the engine's internal mechanisms. Again, note the orientation of the larger, keyed gear. Thoroughly inspect all gears for any damage, such as missing teeth or significant wear. If you find damaged gears, you can often purchase replacement gears and rebuild the pump, which is considerably cheaper than buying a brand-new unit. A good cleaning of all components is also essential during this stage.
Key Component Check: Damaged gears are a definite sign that the oil pump requires either a rebuild or replacement.
Reassembly and Considerations
Once you have inspected, repaired, or replaced the necessary components, the reassembly process is essentially the reverse of removal. Ensure all mating surfaces are clean, new gaskets are used where appropriate, and all bolts are tightened to the manufacturer's specifications. Refill the engine with the correct type and amount of fresh oil, and always double-check for leaks after starting the engine.
Common Oil Pump Issues and Diagnosis
Understanding common oil pump failures can help in diagnosis:
| Symptom | Potential Cause | Action |
|---|---|---|
| Low Oil Pressure Warning Light | Worn gears, faulty pressure relief valve, internal leaks, blocked oil pickup screen. | Inspect pump internals, check oil pickup, test pressure relief valve. |
| Excessive Oil Consumption / Leaks | Cracked pump housing, failed seals, damaged gasket between pump halves. | Inspect housing for cracks, replace seals and gaskets. |
| Noisy Operation (Whining/Grinding) | Worn or damaged gears, lack of lubrication, debris in pump. | Inspect gears for damage, ensure proper lubrication, clean pump assembly. |
Frequently Asked Questions (FAQ)
Q: How often should I check my oil pump?
While there's no fixed mileage for oil pump checks, it's wise to inspect it if you notice symptoms like oil leaks or low oil pressure. Regular oil changes are crucial for maintaining the health of the oil pump and the entire engine.
Q: Can I bypass the oil pump?
No, the oil pump is a critical component for lubricating your engine. Bypassing it would lead to catastrophic engine failure due to a lack of lubrication.
Q: What type of oil should I use?
Always refer to your Harley Davidson owner's manual for the recommended oil type and viscosity for your specific model year. Using the incorrect oil can damage the engine and the oil pump.
Q: Is it normal for some oil to leak when removing the hoses?
Yes, it is normal for a small amount of residual oil to spill when disconnecting the oil lines from the pump. Having shop rags readily available will help manage this.
Q: Do I need to remove the exhaust pipes for easier access?
While professionals might do this for maximum accessibility, it's often not strictly necessary for DIY removal. Be mindful of the exhaust pipes to avoid scratching them or the engine cases during the process.
By following these steps, you can confidently remove and inspect the oil pump on your Harley Davidson Touring motorcycle, empowering you to perform essential maintenance and repairs yourself.
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