Introduction: Black and Decker Hedge Hog HS2400 Type 1 24-inch Hedge Trimmer Cutting Bar Repair
When using this Black and Decker Hedge Hog HS2400 Type 1 24-inch hedge trimmer, the Cutting Bar was observed moving to the side depending on the direction of the cut. The blade moving back and forth (front to back) is expected. The Cutting Bar assembly moving side to side (left to right) is definitely not expected/
The trimmer was checked unplugged because it doesn’t know the difference between 3/4-inch branches and fingers. This is a cutting edge tool and needs to be handled accordingly, even with it unplugged.
The tip of the Cutting Bar assembly moved left and right through about four inches of travel without the Housing moving at all. The measurement was just for reference because the Cutting Bar assembly moving left and right at ALL is wrong.
So what caused the problem? The part that keeps the non-moving parts of the Cutting Bar assembly from moving broke into two pieces. On this trimmer the part is the Gearcase Assembly. I was lucky there was not additional damage because the moving parts are not designed to carry the strain of cutting,
Step 1: What Broke – the Gearcase Assembly
As noted, the cause of the independent movement of the Cutting Bar was that the Gearcase Assembly was broken. The break was where the extension for the Cutting Bar assembly meets the gear housing. The Gearcase Assembly is Number 18 on the parts list as shown below.
Black and Decker obviously became aware of this problem because the replacement part has been redesigned with gussets. The gussets should serve to reinforce the part but time will tell.
I highly recommend looking at a parts drawing before you begin working on the trimmer. Also, read through the Disassembly – Gearcase section before beginning to save time and frustration (e.g. do not unwire anything and do not pull out the Armature.) Oh yeah, and “Don’t cross the streams”.
To find parts diagrams, search HS2400 parts diagrams and select Images. These sites are also the ones selling replacement parts. The Gearcase Assembly (Part #: 90519082) was less than $25.00 USD including tax and shipping. A new 24-inch Black and Decker hedge trimmer is about $65.00 USD plus tax.
2. Compression Spring, trigger
3. Screw Plastite, T-15
5. Armature and field
6. Lower motor casting
7. Bearing Support, upper motor casting
9. Brush holder
10. Lock Button, interlock
11. Screw Taptite, T-20
12. Actuator, trigger
13. Washer Spring
14. Spring, interlock
15. Screw, upper housing
16. Washer Plain
17. Switch, trigger
18. Gearcase Assembly
19. Gear Cover
20. Cutting Bar Assembly
21. Cutting Bar Attachment Bolts
22. Nut Lock
25. No Longer Available
26. Protector Cord
29. Bale Handle
31. ID Label
Step 2: Tools
T15 Torx screwdriver
8mm socket and ratchet
T20 Torx bit and driver
Gloves, if you tend to be careless around edged tools (the trimmer blade)
The small screwdriver is to align the Cutting Bar assembly holes, to press on the drive shaft during disassembly, and to reload the Brushes if necessary.
The T15 needs to be a screwdriver because the bit and driver will not fit down the holes when you disassemble the Housing. Several drivers were tried and none of them worked.
The 8mm socket and ratchet are to remove the bolts holding the Cutting Bar assembly.
T20 Torx bit and driver is needed to generate enough torque to remove the screws holding the Gearcase Assembly in place. A Torx screwdriver alone did not work.
Step 3: Disassembly – Guard and Bale Grip
Make sure the trimmer is unplugged.
Remove four T15 screws from the Guard and slip the guard off the trimmer
Remove four T15 screws from the Bale Grip and slip the grip off the trimmer
Step 4: Disassembly - Housing
Place the trimmer on its side with the holes in the Housing facing up.
Remove all six T15 screws from the Housing. If they do not come out of the holes, be careful that they do not fall out and bounce away when handling the Housing half.
Carefully lift and separate the two halves of the Housing. Do not force anything. A screw may not have been fully extracted. You do not want to break the Housing.
Step 5: Disassembly - Gearcase Assembly
Ok, here are the warnings.
Do not unwire anything.
After the screws are removed from the Gearcase Assembly, make sure you keep pressure on the drive shaft during disassembly. If the Armature comes out, the Brushes fall out. Go to the end of this Ible if this happens.
Remove two T-20 screws
See the second warning above
Tip the motor out of the Housing and remove two T-20 screws but hold the Gearcase Assembly in place.
Use the small screwdriver to put pressure on the drive shaft and separate the Gearcase Assembly
Step 6: Disassembly – Cutting Bar and Reassembly - Everything
Note the orientation of the broken Gearcase Assembly extension
Unbolt the Cutting Bar assembly from the broken Gearcase Assembly extension
Lube the shaft on the new Gearcase Assembly.
Align the Gearcase Assembly shaft and slide into place.
Bolt the Cutting Bar assembly to the new Gearcase Assembly extension
If the holes in the Cutting Bar assembly and the Gearcase Assembly extension do not line up, use the small screwdriver to slide the Cutting Bar assembly into alignment.
Slide the splined drive shaft into the bushing on the Gearcase Assembly. Gently turn the drive shaft using the fan vanes to engage the drive gear. They will slip together easily when engaged.
Install two T-20 screws and tighten.
Tip the motor and Cutting Bar into the Housing and install two T-20 screws and tighten.
Check that the Gear Cover is seated and the motor and Cutting Bar are positioned in the Housing,
Re-mate the halves of the Housing, being careful of the trigger and interlock springs. Do not force anything. If it is not going together, see what is out of place and get it back into place.
When the housings are flush with one another, replace the six T-15 screws and tighten. Do not use the screws to pull the halves together.
Replace the Bale Handle and tighten the four T-15 screws.
Replace the Guard and tighten the four T-15 screws.
Step 7: Recovery – Armature and Brushes
If you are here, you made the same error I did, but it is an easy fix.
Make sure the parts are in order.
The Washer Spring (#13) is on the top shaft of the Armature (#5).
The Washer Plain (#16 flat) is on the bottom shaft of the Armature (#5).
The curvature of the Brushes (#8) is noted (which end is curved).
After checking the washers, slide the Armature fully into the housing. The top shaft slides into the Bearing at the top of the housing.
There is a brush on each side so do one side and then the other.
With the small screwdriver, hook and pull back on the end of the Contactor spring to clear the opening to the Brush holder.
Check that curve of the Brush matches curvature of Armature and the that the curve of the Brush is facing in.
Fully insert the Brush into the Brush holder.
Seat the tip of the Contactor spring on the flat end of the Brush
Repeat for the other side