Troubleshooting and Servicing the Bosch 11316 EVS Hammer Drill

Troubleshooting a Bosch 11316 EVS Hammer Drill That Won't Hammer

A Bosch 11316 EVS hammer drill is a powerful and versatile tool for drilling into concrete, masonry and other tough materials. However, these hard-working tools can develop problems over time, especially if they haven't been properly maintained. One of the most common issues with the Bosch 11316 EVS is when the hammer mechanism stops working properly and the drill won't hammer.

There are several possible causes for a Bosch 11316 EVS hammer drill not hammering properly:

Worn or Damaged Hammer Mechanism

The hammer mechanism itself could be worn out or damaged. This mechanism generates the hammering action and is subject to a lot of wear and tear over the life of the tool. With prolonged use, the hammer mechanism parts like the hammer frame, bearings and piston can become excessively worn and prevent the tool from hammering correctly.

Inspecting the hammer mechanism involves disassembling the gear housing to access the internal parts. Look for any broken or cracked components, excessive wear on contact surfaces, or damage to the piston and bearings. The piston in particular needs to slide smoothly in order to create the hammering movement.

Blocked Hammer Mechanism

Dirt, grease, metal debris or other contaminants entering the hammer mechanism can cause it to bind up and stop the hammering action. This is more likely if the drill has been used for long periods without proper cleaning and maintenance.

To inspect for blockages, disassemble the gear housing and check for any obstructions in the hammer mechanism. Clean out any contaminated grease, dirt or debris. The motion of the piston should be smooth and unimpeded after cleaning.

Broken or Loose Hammer Spring

The hammer spring provides the reciprocating motion that activates the hammer mechanism. If this spring breaks or loses tension, it will no longer be able to move the piston and generate hammering force.

Removing the gear housing provides access to inspect the hammer spring. Look for any cracked or fatigued coils as well as proper tension. The spring should still be strong enough to rapidly compress and expand during operation. If damaged, the entire spring will need replacement.

Faulty Switching Mechanism

The Bosch 11316 EVS uses a special clutch mechanism to switch between rotation only and hammer drilling modes. Issues with the clutch components can prevent the tool from properly engaging the hammer function.

Accessing the clutch requires disassembling the front section of the drill housing. Inspect the activating components like the mode collar, springs and steel balls for any worn or damaged parts. Ensure the mechanism is able to fully engage and disengage when shifting between modes.

Worn Brushes or Commutator

The electric motor brushes and commutator are vital for generating the high speed and torque required for hammer drilling. Excessively worn brushes or damage to the commutator can affect motor performance.

Check that the carbon brushes still have sufficient length and are able to move freely in their holders. The commutator should be clean and smooth, without any burned spots, pitting or scratch marks around the segments.

Weak Magnet in Armature

The magnets inside the armature provide the electromagnetic fields for motor operation. Weakened magnets reduce power output and speed, which affects the hammering action.

Removing the armature makes it possible to check magnet strength around the exterior. Use a gauss meter to compare measurements - significantly lower readings indicate degraded magnets. The entire armature may need replacement if the magnets are found to be too weak.

How to Service a Bosch 11316 EVS Hammer Drill

Completely disassembling a Bosch 11316 EVS hammer drill is required for inspecting and accessing all the internal components. This comprehensive service procedure allows full diagnosis and repair of any issues with the hammer mechanism, motor or switching mechanism.

Tools and Supplies Needed

Here are the basic tools and supplies required for servicing a Bosch 11316 EVS hammer drill:

• Complete hammer drill service kit with assorted screwdrivers, pliers, brushes, bulk o-rings
• Bench vise to securely hold drill during disassembly
• Torque wrench for reassembling gear housing
• Clean rags and degreasing solvent for cleaning parts
• Replacement grease for lubricating gearing
• Multimeter for testing motor windings and switches

Disassembly Procedure

Follow these steps to completely disassemble the hammer drill:

1. Remove chuck with chuck key by rotating counterclockwise.
2. Unscrew gear housing retaining bolts using an impact driver. Separate gear housing from motor housing.
3. Press in and remove armature bearings from front and rear. Lift armature out of motor housing.
4. Take note of brush layout. Remove brush holder caps and lift out brushes and springs.
5. Push commutator end bracket off motor shaft. May require an arbor press.
6. Extract motor field magnet with slide hammer puller tool.
7. Remove clutch components from front of gear housing.
8. Separate gear assembly down to individual parts like bearings, gears and shafts.
9. Drive out piston retaining pins to remove piston and disassemble hammer mechanism.

Inspection and Cleaning

With the drill fully disassembled, inspect and clean all parts:

• Clean housings, gears, bearings with degreasing solvent. Blow out dust with compressed air.
• Inspect all parts for cracks, excessive wear, binding or damaged.
• Check bearing operation by rotating inner and outer races.
• Examine brushes and commutator for wear. Commutator must be smooth.
• Clean any contaminated grease out of hammer mechanism.
• Ensure clutch mechanism fully engages and disengages.
• Check magnet strength on armature exterior with a gauss meter.

Any excessively worn or damaged parts will need replacing with new Bosch factory components to ensure proper operation and reliability.

Reassembly and Testing

Once fully cleaned and inspected, reassemble the hammer drill:

1. Grease and reinstall hammer mechanism components.
2. Rebuild gear assembly with proper shims and preload.
3. Press commutator end bracket onto motor shaft arbor.
4. Install field magnets into motor housing.
5. Insert brushes and holders. Connect pigtail wires.
6. Press armature bearings into front and rear of motor housing.
7. Mate gear housing and motor housing. Torque retaining bolts to specification.
8. Reinstall chuck and tighten firmly.

After reassembly, conduct testing by running the drill at high and low speeds, checking hammer mechanism operation and ensuring proper clutch function. The drill should now be restored to full working order after service.

Maintaining Your Bosch 11316 EVS Hammer Drill

To maximize the lifespan of your Bosch 11316 EVS hammer drill and prevent common issues, follow these maintenance practices:

Regular Inspection

Visually inspect the external housing and check the operation of the chuck, buttons, triggers and switches before each use. Make sure everything functions properly and nothing is cracked or damaged.

Lubrication

Apply light oil periodically to the chuck and keep other exterior surfaces clean. Regrease the gearbox per the manufacturer's recommendations or any time the drill is disassembled for service.

Brush Inspection

Check carbon brush length about every 50 hours of runtime. Replace brushes once they near the minimum length. Inspect the commutator for damage each time brushes are checked.

Cleaning

Use compressed air to blow out dust from the motor vents and housing after each use. This prevents debris buildup that can contaminate the hammer mechanism. Wipe down the external housing with a clean damp cloth.

Storage

Store the drill in a clean, dry place when not being used for extended periods. Engage the safety lock and chuck key before storage.

Repairs

Don't attempt to use the drill if the hammer mechanism is damaged or not functioning. Have it serviced by an authorized Bosch repair center to ensure quality workmanship and parts.

Following proper maintenance and service procedures will keep a Bosch 11316 EVS hammer drill running smoothly for many years of heavy duty use on the jobsite.

FAQs

What are the most common issues that cause a Bosch 11316 EVS hammer drill to stop hammering?

The most common issues are worn or damaged hammer mechanism components, contaminants blocking the mechanism, a broken or loose hammer spring, problems with the mode switching mechanism, worn motor brushes or commutator, or weak magnets in the armature.

How can I tell if the hammer mechanism is worn out?

Disassemble the gear housing and inspect the mechanism - look for excessive wear on contact surfaces, scratching, pitting or damage to parts like the bearings, piston and hammer frame. If parts are very worn, replacement will be needed.

What's involved in fully servicing a Bosch 11316 EVS hammer drill?

Complete disassembly is required to access the inner hammer mechanism and motor components. All parts are thoroughly cleaned, inspected and replaced as needed. Proper reassembly and testing ensures the drill is restored to good working order.

What maintenance should be done to extend the life of a Bosch 11316 EVS?

Regular inspection, lubrication, brush checks, cleaning and storage maintenance are recommended. The gearbox should be re-greased periodically. Brushes and commutator need regular inspection. Always blow out dust after use.

Can I repair the hammer mechanism myself or do I need to send it in?

It's recommended to have an authorized Bosch service center repair any issues with the hammer mechanism to ensure proper workmanship and replacement parts are used.