Question 1

just got this drill and the battery seems to die way faster than my old m18 drill, is something wrong with it?

Accepted Answer

DIAGNOSIS Probably not. The FUEL hammer drill is significantly more powerful than older non-FUEL M18 models. That power comes from drawing more amps from the battery under load, which can drain it faster if you're using it hard. FIX First, check your battery's health. Is it an old battery you're using with a new tool? Older batteries have less capacity. Try a newer, high-capacity battery (like an XC5.0 or HO) and see if runtime improves. Second, consider your use. Are you using hammer mode a lot? That's the highest power-draw function. Are you drilling large holes or driving big lag bolts in low gear? That's also high draw. The tool is working correctly, it's just using the available power. IF THAT DIDN'T WORK If you've tried a known-good, fresh battery and runtime is still abysmal (like 5 minutes on a simple task), there could be an internal short or a binding gear creating excessive drag, making the motor work overtime. Listen for any unusual whining or feel for heat when running with no load. If present, it may need service. HEADS UP Runtime is a trade-off for power. The FUEL technology is about delivering maximum performance, not necessarily maximum runtime from a given battery. For long tasks, plan on having multiple batteries. Also, make sure you're using the right tool for the job—the hammer drill is overkill for small screw driving, where an impact driver or smaller drill would be more efficient and save battery.

Question 2

my drill works but the led worklight doesn't come on anymore, is there a way to check it without taking it all apart?

Accepted Answer

DIAGNOSIS Either the LED itself has burned out (less common) or, more likely, the wire connecting it to the board has come loose or broken, often from vibration or a previous drop. FIX You can do a quick visual check. 1) Look into the light port near the chuck. Is the tiny LED lens visibly cracked or damaged? 2) In a dark area, pull the trigger and look very closely at the light port. Sometimes a very faint glow means it's getting low power from a bad connection. If you see nothing, the next step is internal. The light is part of a small wire harness that plugs into the main board. Fixing it requires opening the housing to check that connection. IF THAT DIDN'T WORK If you open it up and the connection is secure, the LED module is a simple plug-in part you can order. It's not soldered. Unplug the old one and plug in the new one. Before you order the part, use a multimeter to check for voltage at the connector when the trigger is pulled to confirm the board is sending power. HEADS UP The worklight is designed to turn off shortly after you release the trigger to save battery. It's not supposed to stay on. So if your problem is "it turns off immediately," that's normal. The issue here is it never turns on when the trigger is pulled. Also, the light isn't a critical function for operation, so you can keep using the drill safely if you can live without it.

Question 3

i dropped my drill and now the trigger is all loose and sometimes it just starts running on its own, can i fix this?

Accepted Answer

DIAGNOSIS The impact likely cracked the trigger housing internally or dislodged the trigger's return spring. A loose trigger that self-activates is a serious safety issue. FIX You need to open up the drill. This means removing the housing screws. 1) Remove the battery. 2) Take out all the visible screws holding the two halves of the main body together. 3) Gently separate the clamshell. You'll see the trigger assembly mounted to the inside. 4) Check if the plastic trigger piece is broken or if the small metal return spring has popped off its post. If the spring is off, just re-seat it. If the plastic is cracked, the trigger needs replacement. IF THAT DIDN'T WORK If the trigger looks intact and the spring is in place, the drop may have damaged the electronic switch module the trigger presses. This is a soldered circuit board component. At that point, for most people, it's a warranty or service center job, as replacing the switch requires soldering skills. HEADS UP Until this is fixed, treat the tool as live and dangerous. Do not install a battery. A runaway drill can cause injury or damage. If you're not confident opening it up, this is absolutely a case for sending it to Milwaukee for repair. Don't tape the trigger down or try other workarounds.

Question 4

the mode selector ring between drill, hammer, and screwdriver is stuck and i can't turn it, how do i free it up?

Accepted Answer

DIAGNOSIS Grime, concrete dust, or dried-up grease has gotten into the detent ball and spring mechanism under the ring, jamming it in place. FIX Don't force it with pliers—you'll break the plastic ring. 1) Blow compressed air around the base of the ring where it meets the tool body. 2) Apply a penetrant like WD-40 or a silicone spray around that same seam. Let it sit for 10 minutes. 3) Try to gently work the ring back and forth. The goal is to let the lubricant seep in and dissolve the gunk holding the detent ball. 4) Once it moves, work it through all positions repeatedly, adding a bit more spray. IF THAT DIDN'T WORK If it's truly seized, you may need to partially disassemble the gear case to clean the mechanism. The ring is connected to a cam inside. For the 2904-20, this requires removing the chuck and then the front gear housing. This is a repair for someone comfortable with tool teardowns, as you'll need to regrease gears during reassembly. HEADS UP Once freed, keep it moving. Cycle through the modes every couple of weeks if you don't use them often. The most common cause is leaving the tool stored in one position (especially hammer mode) for months in a dirty environment, allowing everything to lock up.

Question 5

why does my m18 fuel drill get super hot right behind the chuck after like 5 minutes of use, even on easy stuff?

Accepted Answer

DIAGNOSIS That heat is coming from the motor and gearbox. On the FUEL model, it's normal for that area to get quite warm under load, but "super hot" quickly on easy tasks suggests excessive friction, often from old or low grease. FIX First, rule out operator error. Are you using the correct speed (gear) for the job? Using high speed (gear 2) for driving large screws or drilling big holes makes the motor work harder and heat up fast. Switch to low speed (gear 1) for high-torque tasks. If you're already in the right gear, the gearbox likely needs fresh grease. This is a more involved teardown, but often just adding a bit through the chuck end (as described in the hammer noise fix) can help lubricate the front bearings and gears. IF THAT DIDN'T WORK Excessive heat can also be from a failing bearing or a motor brush on its way out. Listen closely for any high-pitched whining or grinding that accompanies the heat. If it's just heat with no strange noise, it's probably just hard use. Let it cool down between battery changes. HEADS UP The FUEL tools have a built-in thermal protection that will shut the tool down if it gets dangerously hot. If you're not hitting that shutdown, the heat is likely within design limits, just uncomfortable. That area is basically where all the mechanical power is converted, so it's the hotspot. Using a sharp bit and not forcing the drill excessively is the best way to manage heat.

Question 6

my milwaukee hammer drill makes a horrible grinding noise only when i push the hammer mode button, drilling is fine

Accepted Answer

DIAGNOSIS That's the sound of the hammer mechanism—a spring-loaded ram that hits an anvil—operating without lubrication or with debris inside. In hammer mode, the gears engage that mechanism, and if it's dry or gritty, it grinds. FIX You need to get grease into the hammer mechanism. Milwaukee packs it with grease from the factory, but it can dry out or get pushed out by dust. 1) Remove the chuck (see the other question for how). 2) Look into the spindle where the chuck was. You'll see the front of the hammer anvil. 3) Apply a small amount of high-quality lithium grease (Milwaukee recommends theirs, but any good bearing grease works) around the anvil and the visible parts inside the spindle. 4) Reinstall the chuck. 5) Run the drill in hammer mode (with NO bit, off the work) for 15-30 seconds to work the grease in. IF THAT DIDN'T WORK If the grinding is truly metallic and harsh, the hammer mechanism's internal parts may be broken. A worn or chipped ram or anvil will make a bad noise. At that point, it's a gearcase repair, which for most folks means sending it in for service. HEADS UP Never run the hammer function without the bit pressed against a surface. The mechanism needs the resistance of the material to function correctly. Free-spinning in hammer mode can cause extra wear and isn't good for it. This noise is common if the drill's been used heavily for masonry and never maintained.

Question 7

the chuck on my m18 fuel hammer drill won't tighten all the way, bit just slips no matter what

Accepted Answer

DIAGNOSIS The self-tightening jaws inside the chuck are jammed with debris (concrete dust, metal shavings) or the internal mechanism is worn from not being hand-tightened properly. FIX This is a cleaning job. You'll need a can of compressed air or an air compressor. 1) Open the chuck jaws as wide as they go. 2) Blow air directly into the jaws, angling it to get behind them. Rotate the chuck and repeat. 3) After blowing it out, put a few drops of light machine oil (like 3-in-1) on the chuck threads—the part that moves when you turn the sleeve. 4) Work the chuck open and closed by hand a dozen times to work the oil in and loosen any grit. IF THAT DIDN'T WORK If it's still slipping, the jaws themselves might be worn smooth. For the 2904-20, the chuck is a replaceable part. You can order a new Rohm or Milwaukee chuck. Replacing it requires locking the spindle with an Allen key (usually a 10mm) and using a pipe wrench or chuck key to unscrew the old one—it's reverse threaded. HEADS UP Always hand-tighten the chuck firmly after using the tool's power to snug it. Relying solely on the drill's burst to tighten puts all the stress on the internal gears and wears the chuck faster. A good clean and lube every few months if you're in dirty environments makes a huge difference.

Question 8

my milwaukee m18 fuel hammer drill just flashes red and green on the battery and won't run at all, what's wrong?

Accepted Answer

DIAGNOSIS That's the battery's fault indicator. It means the battery pack's internal protection circuit has tripped, usually from a voltage imbalance between the cells or a thermal event. FIX First, take the battery off the tool. Let it sit off the charger and the drill for a good 30 minutes to cool down and reset. Then, pop it onto a Milwaukee M18 charger. If it's a genuine fault, the charger lights will usually just blink or show an error and won't charge. If it starts charging normally after the cool-down, you likely just overheated it. Let it charge fully, then try it on the drill again. IF THAT DIDN'T WORK If the charger still won't recognize it or it immediately flashes again on the tool, the battery pack itself is probably faulty. For the 2904-20, this is almost always a battery issue, not a drill issue. Try a different, known-good M18 battery on your drill to confirm the drill works. If it does, your original battery needs service or replacement. HEADS UP Don't keep trying to force a faulty battery to work. A tripped protection circuit is there for safety. Continuing to try can prevent it from ever resetting and might be a sign of a failing cell, which you don't want to risk.

Question 9

just got this drill and the chuck wobbles a little bit, is it defective?

Accepted Answer

DIAGNOSIS Chuck wobble indicates a manufacturing defect or damage. The chuck is not seated perfectly perpendicular to the spindle, or the spindle itself is bent. FIX Test with a known-true drill bit. Install a new, high-quality bit and tighten the chuck fully. Observe the bit tip while running the drill at low speed with no load. Visible wobble at the bit tip confirms the issue. For a new tool, this is a warranty claim. IF THAT DIDN'T WORK If the bit doesn't wobble but the chuck body does, the chuck is defective. The 2904-20 uses a Rohm chuck. It can be replaced, but misalignment could also be in the spindle taper. A service center can determine the root cause. HEADS UP Using a drill with a wobbly chuck accelerates wear on the gearbox bearings and produces inaccurate, oversized holes. Address it immediately.

Question 10

trigger feels sticky and sometimes the drill keeps running after i let go.

Accepted Answer

DIAGNOSIS Contamination inside the trigger switch assembly or a failing return spring. Dust and debris are the most common cause. FIX Clean externally. Remove battery. Use contact cleaner with a thin straw nozzle. Spray into the gaps around the trigger while working it back and forth. Allow to dry completely. Do not use lubricating oils. IF THAT DIDN'T WORK The switch mechanism itself is damaged. The 2904 uses a sealed electronic switch module. If cleaning fails, the entire trigger/switch assembly must be replaced as a unit. It is not field-repairable. HEADS UP A sticking trigger is a serious safety hazard. Do not use the tool until this is resolved. If the tool runs on, immediately remove the battery to prevent injury or damage.

Question 11

my drill gets super hot really fast, even just drilling wood, is that normal?

Accepted Answer

DIAGNOSIS Rapid overheating under light load is abnormal. Primary cause is excessive friction from worn gears or a failing motor bearing. FIX Isolate the issue. Run the tool with no load for 30 seconds. If it gets hot at the motor housing, the motor or armature bearing is failing. If heat is concentrated in the gear housing near the chuck, the gearbox has insufficient or contaminated grease, or gears are damaged. IF THAT DIDN'T WORK An electrical fault can cause overheating. A shorted winding in the motor or a failing controller can cause the motor to draw excessive current, generating heat immediately. This requires motor or board replacement. HEADS UP The tool has thermal protection, but chronic overheating will degrade plastic components and permanent magnets in the motor, leading to irreversible power loss.

Question 12

the mode selector ring is stuck and i can't switch from drill to hammer.

Accepted Answer

DIAGNOSIS The selector ring is jammed by debris or a damaged detent spring/ball inside the gear housing. FIX Clean externally first. Remove battery. Use a stiff brush and dry air around the selector ring base. Attempt to turn the ring while gently pulling the trigger in short bursts (no battery) to slightly move internal gears. If it frees up, work it back and forth and clean thoroughly. IF THAT DIDN'T WORK Internal damage. A common failure point is the nylon selector cam or the steel detent ball/spring behind it. This requires disassembly of the front gear housing to inspect and replace the damaged components. HEADS UP Do not force the selector ring with pliers. You will shear the plastic cam inside, necessitating a full gear case teardown and replacement of multiple parts.

Question 13

how do i clean out all the concrete dust from inside my hammer drill after core drilling?

Accepted Answer

DIAGNOSIS Concrete dust ingress is abrasive and can jam the hammer mechanism, overheat the motor, and cause switch failure. FIX Use dry, filtered air. Remove the battery. Blow air into the vents, the chuck area, and the mode selector switch. Manually rotate the chuck while blowing. Do not use compressed air over 100 PSI. Do not disassemble the gear case unless qualified. IF THAT DIDN'T WORK For persistent grinding or clicking, the hammer mechanism pins and springs may be packed with fines. This requires complete gear case disassembly, cleaning, and re-greasing with Milwaukee specified grease. HEADS UP Never spray lubricants like WD-40 into the tool to clean it. This attracts more dust and can damage plastic and electrical components. Use only dry air or a soft brush.

Question 14

drill seems weak, bogs down way easier than it used to with a fresh battery.

Accepted Answer

DIAGNOSIS Reduced power output. This is typically caused by worn motor brushes or a failing field controller, not the battery. FIX Confirm it's not the battery. Test with multiple known-good, high-output M18 batteries (e.g., XC5.0 or HO). If performance is consistently weak, inspect the brushes. On the 2904, this requires disassembly. Look for brushes shorter than 1/4 inch or springs not making contact. IF THAT DIDN'T WORK The electronic variable speed trigger or the power module may be failing, sending incorrect current to the motor. This is not user-serviceable. Tool needs professional diagnostics. HEADS UP Using the tool in hammer mode on concrete for extended periods generates extreme heat. Chronic overheating is a primary cause of electronic component degradation and power loss.

Question 15

hammer drill light is flashing red and green, what does that mean?

Accepted Answer

DIAGNOSIS The red/green flashing LED indicates a communication error between the tool and the M18 REDLITHIUM battery. The tool has detected a potential fault. FIX Perform a reset. Remove the battery. Press and hold the trigger for 30 seconds to discharge capacitors. Reinstall a known-good, fully charged battery. If the error clears, the original battery may be the issue. Test the original battery on another M18 tool. IF THAT DIDN'T WORK The fault is likely in the tool's battery terminal interface or main control board. Clean the battery terminals on the tool and battery with a dry cloth. If error persists, the tool requires service. HEADS UP This flash pattern is different from a simple low-battery warning. A flashing red light alone indicates low battery. Red/Green flash is a tool/battery communication fault.

Question 16

my m18 fuel hammer drill just makes a clicking noise and won’t spin, battery is fully charged.

Accepted Answer

DIAGNOSIS The drill's motor controller or electronic clutch is preventing operation due to a fault detection. The most common cause is a damaged or obstructed chuck. FIX Inspect the chuck and spindle. Remove the battery. Manually rotate the chuck. Check for foreign material. If it rotates, reinstall the battery and attempt to run the tool in a non-hammering mode with no load. If the chuck is visibly damaged or wobbles, it requires replacement. IF THAT DIDN'T WORK The issue is internal. The primary suspects are a failed motor controller board or a damaged trigger assembly. This requires professional service at a Milwaukee service center. HEADS UP Do not continue to pull the trigger if the tool clicks repeatedly. This can overheat and permanently damage the motor or electronics.

Milwaukee M18 FUEL Hammer Drill 2904-20

Other Power Tools