How to Repair Rust Holes Around the Wheel Well

Rust holes around the wheel well are a common issue, especially for older vehicles in areas that use salt on the roads in winter. The salt causes the metal around the wheel wells to corrode and rust over time. Repairing rust holes properly takes some work, but it’s doable for the average DIYer with the right tools and techniques. This comprehensive guide will walk you through the full process of repairing rust holes around the wheel well to stop further rust damage and make your vehicle look great again.

Assessing the Damage

The first step is to thoroughly assess the area and determine how extensive the rust damage is. Here are some tips for inspecting the wheel well:

  • Use a flashlight to look inside the wheel well and inspect all surfaces for holes, flaking metal, bubbling paint, etc. Check both the inner and outer surfaces.
  • Remove the tire to get better access if needed. This allows you to check the entire perimeter of the wheel well.
  • Probe any suspect areas with a screwdriver or awl to check how deep the rust goes. Knocking with a hammer can also help detect soft spots.
  • Look for signs of rust under the paint, like cracks or bubbles. This indicates the rust is spreading under the surface.
  • Determine how large the affected area is and how far you’ll need to grind/sand to reach solid metal. Mark the areas that need work with chalk.

Take your time inspecting to fully understand the scope of rust damage. The size and location of holes will determine how extensive repairs need to be.

Gather the Right Materials

Repairing wheel well rust requires an assortment of supplies. Here are the materials you’ll need:

  • Grinder or sander – To remove paint/rust and grind down to bare metal
  • Sandpaper – For smoothing metal edges
  • Patch panels – New replacement metal panels for larger holes
  • Body filler/putty – Such as Bondo to fill holes and depressions
  • Fiberglass cloth – For reinforcing and strengthening repairs
  • Primer – To coat bare metal before painting
  • Paint – Matching original wheel well color
  • Masking tape – For clean paint lines
  • Rust converter – Converts rust to inert layer and prevents spread
  • Rust inhibitor – Added protection after repairs are complete
  • Safety gear – Gloves, goggles, respirator mask, etc.

Make sure you have all the necessary materials before starting repairs for a smooth process. Prepare the repair area by cleaning and removing any dirt or debris.

Grinding Out the Rust

With your supplies gathered, it’s time to tackle the rust damage. The first step is using a grinder or sander to remove all of the rust down to bare, solid metal:

  • Start grinding – Use a wire wheel or flapping disc attachment to efficiently grind away rust/paint.
  • Work outwards – Start from center of rust holes and work outwards to find solid metal.
  • Go slow – Take your time to thoroughly remove all rust and avoid over-grinding good metal.
  • Keep things cool – Periodically stop to cool the area and prevent warping the metal.
  • Inspect as you go – Check for pitting, holes or soft spots as they will need extra attention.
  • Grind problem spots – Use a rotary sander to flatten pits/holes down to solid metal.
  • Smooth edges – Use sandpaper to feather and smooth all rough edges.

Thoroughly grinding down to bare metal is crucial to prevent the rust from coming back. Be patient and keep grinding until only clean, solid metal remains.

Applying Patch Panels for Larger Holes

For holes larger than a few inches, you’ll need to weld in new patch panels to cover the area:

  • Buy patch panels to match your vehicle make and model. They are shaped specifically for wheel wells.
  • Cut and trim the patch panel to overlap the hole by at least 1 inch all around.
  • Clamp or tack weld the panel in place. Ensure good fitment with no gaps.
  • Weld the patch panel fully in place with an overlapping butt joint or plug weld.
  • Grind/sand welds smooth. Seal with rust converter.

Patch panels provide properly contoured metal pieces that are easier to weld in than fabricating your own patches. Take care to position them precisely before welding.

Applying Body Filler and Smoothing

For small holes under a few inches, applying body filler/putty is an easier alternative to welding:

  • Apply thin coats of filler and use a spreader to smooth. Allow to fully cure between coats.
  • For deeper holes, pack filler/fiberglass strips to build up layers.
  • Sand filler with 80-120 grit sandpaper to blend with surrounding metal.
  • Skim coat entire area with thin layer of filler for a smooth finish.
  • Prime and sand the filler to prep for paint.

Take your time applying filler to create a seamless, factory-quality repair. Proper sanding technique helps hide any imperfections.

Strengthening the Repair

To prevent cracks and further rust, it’s important to strengthen and reinforce your repairs:

  • Apply fiberglass cloth to the inside of the wheel well over holes/patches. Resin helps harden and strengthen the area.
  • Use body filler reinforced with fiber strands for added durability.
  • Apply rust converter to all bare metal areas. This chemically converts rust and seals the surface.
  • Coat the inside of the wheel well with rust inhibitor/rubberized undercoating for further protection.

These extra steps help create repairs that will last and resist rust much longer than just filler and paint alone.

Priming, Painting and Finishing

The final step is to make your repair look factory-fresh with a professional quality finish:

  • Mask off surrounding area with painter’s tape and plastic sheeting.
  • Apply 2-3 coats of sandable primer, sanding between each coat.
  • Spray on color matched paint in multiple coats until fully covered. Allow proper dry time between coats.
  • Finish with clearcoat for protection and sheen. Wet sand and buff for best results.
  • Carefully mask off and paint wheel/tire to complete the job.
  • Install wheel/tire and admire your work!

Take your time prepping and painting to achieve a flawless, seamless finish. Your repaired wheel well should now look brand new and rust-free.

Preventing Future Rust Damage

Completing rust repairs also requires taking steps to prevent future rust. Here are some tips:

  • Wash undercarriage regularly to remove salt and debris buildup.
  • Apply rust inhibitor spray or coating annually to vulnerable areas.
  • Address paint chips, scratches, etc. quickly to prevent rust taking hold.
  • Store vehicle in dry covered area to limit rust exposure.
  • Consider undercoating vehicle for added protection in salty climates.
  • Maintain thorough maintenance and inspection routine to stay ahead of rust.

Keeping your vehicle clean and addressing issues early is key for rust prevention. Be diligent about prevention to protect your repair work.

Tips for Smooth Repairs

Here are some additional tips to help your wheel well rust repair go smoothly:

  • Work in a clean, dry area to limit contamination of repair surfaces.
  • Only work on small sections at a time for best results.
  • Let filler, primer and paint fully cure between coats. Rushing can ruin the finish.
  • Practice metal finishing techniques on scrap metal before tackling visible repairs.
  • Follow all safety precautions when using power tools, paints, chemicals, etc.
  • Consult a body repair professional if you don’t feel equipped to complete the repair.
  • Invest in high quality auto body supplies for repairs that truly last.

Patience and proper process are key for repairing wheel well rust. Don’t cut corners or rush the job.

Common Wheel Well Rust Repair Mistakes

It’s easy to make missteps when repairing wheel well rust. Be aware of these common mistakes:

  • Not fully removing all rust before applying filler/paint
  • Failing to smooth/feather rough edges before applying filler
  • Using excessive filler thickness that can eventually crack or fall out
  • Neglecting to reinforce repairs with fiberglass or rust converter
  • Inadequate surface prep before painting that causes peeling/flaking
  • Rushing paint/filler curing times leading to problems down the road
  • Masking off too small of area and ruining surrounding paint
  • Skipping rust prevention steps after repairing

Learn from other’s mistakes to ensure high quality repairs that truly last. Taking shortcuts usually leads to poor results.

When to Seek Professional Help

While many rust repairs are DIY friendly, there are times you may want to hand it over to the professionals:

  • If the rust is widespread underneath the vehicle
  • For extensive rust holes needing large patch panel fabrication/welding
  • If you don’t have the necessary tools and workspace
  • If you lack experience with auto body filler, painting, etc.
  • For repairs needing a perfect color match or blend with other panels
  • If you don’t have time for the lengthy rust repair process
  • For repairs to critical suspension, steering or safety components

Seeking professional help can be wise for extensive repairs or those affecting crucial systems. The cost is often worth it for the expertise and quality results.


With the right techniques and materials, repairing rust holes around the wheel well is totally doable for a DIYer. Just take your time and don’t cut corners. Thorough surface prep, proper filler use, reinforcing/sealing repairs, and high quality painting are the keys to success. Pay close attention to rust prevention after finishing repairs to protect your hard work. With patience and care, you can stop wheel well rust in its tracks and have your vehicle looking great again.

Key Takeaways:

  • Inspect carefully to assess full extent of rust damage before starting
  • Grind down completely to remove all rust and reach solid metal
  • Weld in new patch panels for larger holes, using body filler for small holes
  • Reinforce repairs with fiberglass cloth and rust converter/inhibitor
  • Allow proper dry times between filler, primer and paint coats
  • Prevent future rust with regular washing, inspections, and rust-proofing
  • Seek professional help for extensive repairs or those affecting safety

Citations: [1] [2] [3] [4] [5] [6]

Installing a tachometer on your motorcycle can be a great way to monitor your engine’s revolutions per minute (RPMs), ensuring you don’t over-rev the engine. A tachometer allows you to shift at optimal times for performance and engine life.

Wiring a tachometer is not overly complex, but does require attention to detail. In this comprehensive guide, we’ll walk through the complete process of installing and wiring an aftermarket tachometer on your motorcycle.

Benefits of Adding a Tachometer

Here are some of the key benefits of installing a tachometer on your motorcycle:

  • Prevent Over-Revving: The tachometer displays your engine RPMs, allowing you to avoid exceeding the redline and potentially damaging internal engine components.
  • Optimize Shifting: Keeping an eye on the tachometer allows you to shift at ideal RPMs for maximum performance and engine life.
  • Monitor Engine Load: Watching the tachometer can give you a sense of how hard you’re working the engine in different riding scenarios.
  • Troubleshoot Problems: Unusual tachometer readings can indicate potential issues like ignition or valve train problems.
  • Improve Safety: Keeping RPMs in check can prevent loss of control from abrupt power changes.

Tachometer Styles

There are a few main types of tachometers to consider:

  • Analog: The classic style with a physical needle that sweeps an arc to indicate RPMs. Easy to view at a glance.
  • Digital: Displays a numeric RPM reading, often with shift light indicators. Easier to get precise readout.
  • Combo Units: Combine analog and digital displays in one gauge for best of both worlds.
  • Dedicated Units: Display only the tachometer function. Good for minimalism.
  • Multi-Function: Integrate tachometer into unit with speedometer, odometer, etc. More info in one place.

Choose the style that best fits your motorcycle setup and visual preferences.

Wiring Overview

We’ll be covering complete step-by-step wiring instructions, but here is an overview of the process:

  • Mount the tachometer securely on the motorcycle.
  • Run power wires from the battery to the gauge.
  • Connect a signal wire from the tach to the ignition coil.
  • Ground the tachometer wires to chassis.
  • Connect illumination wires if needed.
  • Start motorcycle and calibrate the tachometer.
  • Test operation and make any adjustments.

Proper connections and wire routing are critical, so we’ll go through each step in detail.

Step 1: Mount the Tachometer

The first step is finding a suitable mounting location for the tachometer on your motorcycle. Some options to consider:

  • Handlebar mounts: Great visibility while riding. Ensure wires don’t interfere with controls.
  • Fork stem mounts: Also very visible. Make sure wires don’t bind when turning.
  • Frame mounts: Useful for minimalist looks. May need to glance down more.
  • Combination gauge mounts: If adding tachometer to existing cluster.
  • Custom fabricated brackets: For unique mounting solutions.

You’ll need to measure carefully and select the proper diameter clamp for the bars or location you select. The tachometer should be oriented so it’s easy to read when riding.

Once you’ve determined the ideal mounting spot, secure the tachometer tightly using the manufacturer supplied hardware. Don’t fully tighten yet in case you need to adjust the angle.

Step 2: Run Power Supply Wires

The tachometer will require a 12 volt power source to operate. This is typically run directly from the motorcycle’s battery.

Here is the process for running power wires:

  • Cut a length of 16 or 18 AWG wire long enough to reach from the tachometer to the battery area. Red is positive, black is negative.
  • Run the wire along the frame, securing it neatly with zip ties. Avoid any hot or moving parts.
  • Install an automotive grade fuse holder with a 1 amp fuse inline on the positive wire for safety.
  • Connect the positive (red) wire to the positive battery terminal, or any 12V+ connection that is live when ignition is on.
  • Connect the negative (black) wire to the negative battery terminal or a grounding point on the motorcycle frame.
  • Connect the power wires to the corresponding terminals on the tachometer. Consult the manufacturer diagram.
  • Seal any wire connections with heat shrink tubing or electrical tape.

With the 12V+ and ground connections made, the tachometer will have power. But it still needs the engine signal to operate.

Step 3: Connect Signal Wire to Ignition Coil

The tachometer determines engine RPMs based on electrical pulses from the ignition system. This signal wire connects to the negative side of the coil.

Follow this procedure to connect the signal wire properly:

  • Locate the negative coil terminal. Consult a service manual for your motorcycle if needed.
  • Cut a length of 18 or 20 AWG wire to reach from there to the tachometer.
  • Use a spade terminal to connect to the negative post on the coil.
  • Route the wire neatly along the frame with zip ties and avoid any hot or moving parts.
  • Connect the other end to the signal input on the tachometer. Consult the wiring diagram.
  • Make sure the connection is clean and tight. Seal with electrical tape.

The tachometer can now read the engine RPM signal from the coil and display it on the gauge.

Step 4: Ground the Tachometer

For proper operation, the tachometer itself must be electrically grounded to the motorcycle frame.

  • Cut an appropriate length of 16 or 18 AWG black wire.
  • Connect one end to the ground terminal on the tachometer. Consult the wiring diagram.
  • Connect the other end to a suitable grounding point on the metal frame of the motorcycle.
  • Make sure this completes the ground circuit with a good chassis connection.
  • Seal and secure all ground wire connections to prevent issues.

Step 5: Connect Illumination Wiring (If Equipped)

If your tachometer has built-in lighting for night visibility, wiring the illumination is the final electrical step.

  • Run a wire from the lighting power source to the gauge illumination input. Can tap into headlight or marker light power.
  • Connect the other wire end to the illumination feed on the tach. Verify polarity.
  • Ground the other illumination wire as shown in the diagram.
  • Testing the headlight or marker lights should make the gauge light up.

That completes the basic electrical wiring of the tachometer. Now it’s time for calibration and testing.

Step 6: Calibrate the Tachometer Reading

With everything wired up, the tachometer should be powered on and reading engine RPMs. But the reading may not be accurate yet without calibration.

Here is how to calibrate:

  • With engine off, turn ignition on so tachometer powers up.
  • Start engine and compare actual RPMs to tachometer reading. Verify with service manual specs.
  • If reading is off, consult tachometer instructions for calibration procedure. Often there is a potentiometer that can tweak the signal.
  • Rev engine and adjust until tachometer readout matches actual RPMs.
  • Confirm accurate readings across low, mid, and high RPM ranges.
  • Re-check calibration and make adjustments as needed if the tachometer is off.

Step 7: Test Tachometer Operation

Once installation is complete, thoroughly test operation of the tachometer before considering the job done.

  • Turn ignition on and off to verify proper power up and down behavior.
  • Start engine and rev through entire RPM range while observing tachometer.
  • Readings should be smooth and consistent with no jumps or drops.
  • Allow engine to warm up and re-check calibration. Adjust if needed.
  • Visually inspect all wiring connections for security.
  • Take a test ride while frequently checking the tachometer function.
  • Make final mounting angle adjustments if visibility needs improvement.
  • Confirm no wires are binding or chafing during full lock steering.

If everything checks out, the tachometer is fully installed and ready to monitor RPMs on the road!

Troubleshooting Tachometer Issues

If your newly installed tachometer is not working properly, here are some troubleshooting tips:

  • No power – Check fuse, connections to battery, ground wire.
  • No reading – Verify coil signal wire connection.
  • Reading stuck at 0 – Check for loose ground or signal connections.
  • Reading inaccurate – Re-calibrate, check signal wire routing.
  • Reading erratic – Could be loose wire, defective gauge, or bad coil signal.
  • Dim or no illumination – Check wiring from lights, ground connection.

Carefully inspect all wiring and connections to identify the cause of any issues. Also consult the tachometer manufacturer troubleshooting guidance.

Tachometer Installation Tips

Here are some additional tips to ensure your tachometer installation goes smoothly:

  • Use quality wire, terminals, connectors to avoid issues.
  • Follow wiring diagram precisely, double checking connections.
  • Route and secure wires neatly to prevent hazards.
  • Seal connections properly to avoid corrosion.
  • Confirm suitable tachometer signal from coil before wiring.
  • Use extreme caution working around battery, fuel sources.
  • Double check orientation for ideal visibility.
  • Verify clearance for any steering and suspension movement.

Taking it slow and methodically following each wiring step is key to a successful installation.


Adding a tachometer to your motorcycle is a great upgrade that provides valuable performance and engine monitoring capabilities. With some mechanical aptitude and basic electrical knowledge, wiring a tachometer is a very achievable DIY project. Just take it step-by-step.

This guide has walked through the complete installation process, from selecting the right tachometer to troubleshooting any issues. Follow the wiring diagrams precisely, make good connections, route wires neatly, and double check your work. Before you know it, you’ll be able to keep an eye on engine RPMs right on your handlebars. Ride safe!

Key Takeaways:

  • A tachometer allows you to monitor RPMs to prevent over-revving and optimize shifting.
  • Mount the tachometer securely in an optimal visible location on the motorcycle.
  • Run 12V power wires directly from the battery to the tachometer.
  • Connect the tach signal wire to the negative terminal of the ignition coil.
  • Make sure to ground the tach wires properly to the chassis.
  • Calibrate the tachometer reading with a known RPM source.
  • Carefully test all functions before riding with the newly installed tachometer.

Citations: [1] [2] [3] [4] [5] [6]

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