the battery doesn't click in solid anymore, it feels loose and can lose connection if i shake the tool

Diagnosis

The instability in the battery connection of the Milwaukee M18 Fuel Impact Driver (2953-20) is almost always caused by a failure in the mechanical locking mechanism located within the tool's battery shoe. The tool relies on two spring-loaded plastic latch levers that engage with the recesses on the top of the M18 battery pack. Over time, the high-tension torsion springs that drive these levers can fatigue, lose their "spring rate," or snap entirely. When this happens, the levers do not apply enough downward pressure to lock the battery's locking tabs, leaving the battery sitting loosely in the rails. This issue is exacerbated by the high-vibration nature of the 2953-20 impact driver. Because this tool generates significant rotational and linear torque, any slight gap between the battery terminals and the tool's internal contact pins will cause intermittent power loss. You can confirm this by inserting a battery and gently pulling upward; if the battery lifts more than 2-3mm without the latch resisting, or if the tool cuts out during a simple shake test, the internal latch springs have failed or the plastic levers have worn down. In some cases, debris like drywall dust or sawdust has packed into the spring housing, preventing the lever from fully extending.

How to Fix It

Since the 2953-20 is a sealed unit, replacing the internal latch springs requires a partial teardown of the tool housing. Follow these steps precisely to restore the lock tension:

1. Remove the M18 battery and use a T10 Torx driver to remove the screws securing the plastic clamshell housing. Be careful not to strip the screws, as the plastic bosses are soft.
2. Carefully separate the two halves of the housing. Avoid pulling them apart violently, as there are internal wires connecting the trigger assembly to the motor.
3. Locate the battery shoe assembly. Identify the two black plastic latch levers. Inspect the small metal torsion springs located at the pivot point of each lever.
4. If the springs are stretched or snapped, remove them using needle-nose pliers. Replace them with high-tension replacement springs (standard M18 shoe springs). If you cannot source the exact part, a heavy-duty spring from a similar M18 tool can be transplanted.
5. Clean the pivot points of the levers using a cotton swab and 90% isopropyl alcohol to remove any grit or debris that may be hindering the spring's travel.
6. Reinstall the springs, ensuring the long leg of the spring is seated firmly against the housing wall to provide maximum leverage.
7. Snap the housing halves back together and tighten the T10 screws firmly, but do not over-torque, or you will crack the casing.
8. Insert the battery; you should hear a loud, distinct "click" and feel zero vertical movement when pulling up on the pack.

If That Didn't Work

• Check the battery pack itself. Inspect the plastic locking tabs on the top of the M18 battery. If the tabs are rounded off or cracked, the tool's latches will have nothing to grip. Try a different, newer battery pack to determine if the fault lies with the tool or the specific battery.
• Inspect the battery terminal rails. If the side rails of the tool's battery shoe are widened or warped, the battery will wobble side-to-side, preventing the latches from aligning. If the rails are worn, you can apply a very thin strip of heat-shrink tubing or electrical tape to the inside of the rails to tighten the fit.
• Examine the copper contact pins inside the tool. If the pins have lost their tension (they don't "spring back" when pushed), the battery may be physically locked but still lose electrical connection. Use a small pick to gently bend the pins slightly outward to ensure a tighter grip on the battery terminals.
• Replace the entire battery shoe assembly. If the plastic levers are cracked or the pivot holes have ovaled out, replacing the springs won't help. You will need to source a replacement battery base assembly (shoe) from a donor 2953-20 or compatible M18 Fuel tool.

Heads Up

• Avoid "forcing" batteries into the tool if they don't click immediately; this is the primary cause of spring fatigue and plastic lever snapping.
• Periodically blow out the battery port with compressed air to prevent conductive dust or debris from jamming the latch mechanism.
• When using high-capacity batteries (like the 8.0Ah or 12.0Ah HD packs), the extra weight increases the leverage on the latches; check the tightness of your connection more frequently when using these larger packs.
• Do not lubricate the battery latches with WD-40 or grease, as this attracts metallic dust which can cause electrical shorts or jam the spring mechanism.