Makita
Gas Line Trimmer

Model #RBC321 Official Makita string trimmer

Here are the diagrams and repair parts for Makita RBC321 string trimmer, as well as links to manuals and error code tables, if available.

There are a couple of ways to find the part or diagram you need:

  • Click a diagram to see the parts shown on that diagram.
  • In the search box below, enter all or part of the part number or the part’s name.

Not all parts are shown on the diagrams—those parts are labeled NI, for “not illustrated”.

We encourage you to save the model to your profile, so it’s easy to access parts and manuals for your appliance whenever you log in.

For DIY troubleshooting advice and repair guides, visit our repair help section.

    Showing 10 of 129 parts

    Hex Wrench#404

    String trimmer Diagram

    Hex wrench

    Part #783202-0

    The manufacturer no longer makes this part, and there's no substitute part

    S.H. BOLT M5X33 (4)#13

    String trimmer Diagram

    S.h. bolt m5x33 (4)

    Part #011-90598-60

    The manufacturer no longer makes this part, and there's no substitute part

    Clutch#37

    String trimmer Diagram

    Clutch

    Part #627-20030-00

    The manufacturer no longer makes this part, and there's no substitute part

    S.H. BOLT M5X18 (2)

    See All Related Diagrams

    S.h. bolt m5x18 (2)

    Part #011-90599-50

    The manufacturer no longer makes this part, and there's no substitute part

    Primer Pump#114

    String trimmer Diagram

    Primer pump

    Part #524-60011-50

    The manufacturer no longer makes this part, and there's no substitute part

    METERING DIAPHRAGM GASKET#109

    String trimmer Diagram

    Metering diaphragm gasket

    Part #523-60460-40

    The manufacturer no longer makes this part, and there's no substitute part

    SCREW M5X50 (2)#127

    String trimmer Diagram

    Screw m5x50 (2)

    Part #014-00597-30

    The manufacturer no longer makes this part, and there's no substitute part

    Piston#58

    String trimmer Diagram

    Piston

    Part #531-25006-00

    The manufacturer no longer makes this part, and there's no substitute part

    RING PACKING#115

    String trimmer Diagram

    Ring packing

    Part #523-60180-20

    The manufacturer no longer makes this part, and there's no substitute part

    BALL BEARING #6200DDU#27

    String trimmer Diagram

    Ball bearing #6200ddu

    Part #060-01099-70

    The manufacturer no longer makes this part, and there's no substitute part

    Symptoms for gas line trimmers

    Choose a symptom to see related grass line trimmer repairs.

    Main causes: cracked fuel lines, bad carburetor seals, leaky fuel tank cap, damaged fuel tank
    Main causes: stale fuel, cracked fuel lines, dirty carburetor, bad spark plug, worn piston rings
    Main causes: stale fuel, clogged fuel filter, faulty spark plug, clogged air filter, cracked fuel lines, clogged carburetor

    Repair guides for gas line trimmers

    These step-by-step repair guides will help you safely fix what’s broken on your grass line trimmer.

    October 1, 2013
    By Lyle Weischwill
    How to rebuild a line trimmer carburetor

    If the line trimmer engine won't start even though there's fuel in the tank, the carburetor could be the problem. Follow these instructions to do the job in under 30 minutes.

    Repair difficulty
    Time required
     15 minutes or less
    October 1, 2013
    By Lyle Weischwill
    How to replace a line trimmer carburetor

    If the line trimmer won't start even though there's fuel in the tank, the carburetor could be the problem. Follow these instructions to replace the carburetor in under 30 minutes.

    Repair difficulty
    Time required
     15 minutes or less
    October 1, 2013
    By Lyle Weischwill
    How to replace a line trimmer fuel line

    The fuel line on a grass line trimmer deteriorates with time and eventually can split or crack. You can replace it yourself, following these instructions.

    Repair difficulty
    Time required
     15 minutes or less

    Articles and videos for gas line trimmers

    Use the advice and tips in these articles and videos to get the most out of your grass line trimmer.

    August 30, 2022

    How to enjoy all the online benefits we offer on our Sears PartsDirect website

    By Lyle Weischwill

    Learn about all the convenient features on our Sears PartsDirect website that make your parts purchases easier.

    June 1, 2016

    Tips for a hard-to-start grass line trimmer

    By Lyle Weischwill

    These tips may help you get your hard-to-start gas line trimmer running.

    March 1, 2016

    Grass line trimmer maintenance checklist

    By Lyle Weischwill

    Find out how to take care of your grass line trimmer from the start of the trimming season until the end, with this helpful maintenance checklist.