Armature problems Can anyone tell me how to remove the armature for inspection on a makita 5" angle grinder model 9005b?

Buy the new brushes from the manufacturer. You already have the old ones out - put the new ones in the same way you took the old ones out.

It is time to replace the trigger switch.

yes there is, go to "makitausa.com" and with your model number you can download a breakdown for these tools. There is a plastic cap that snaps on the pin, you will have to replace the cap also but after removing the gear housing you pry the cap off and them remove the lock pin. Clean the area on top before reinstalling. Let me know if you need more assistance and I would need the model numbers so I can give you part number.

If it is the one listed in the header 9005B first unplug the tool and then get a good screwdriver and you will find 2 brush caps that need to be removed and pull the brushes out, Be careful not to crack the brush caps and if you do think about replacing them. Let me know if you need more assistance.

Go to www.makitatools.com, type 9005 in the search block and you'll get a page where you can get the manual and parts break down in PDF format. The spindle nut wrench is Part #782412-6 and can be bought at most power tool stores or ordered on line at places like ereplacementparts.com.

Yes, the rock dust is what's destroying your brushes and armatures. It gets sucked into the rear vent slots and gets to those parts and eats them away quickly. I don't know of any vacuum systems make by Makita but there are some companies that make them for their systems. Blastrac is one that comes to mind but they can be real expensive systems. I don't know of any grinders with sealed brush/armature systems, they have too much heat to disipate. To make your Makita grinders last longer make sure you are cutting with the side of the blade that directs the dust away from the case and try to have a strong airflow blowing the dust away from the grinder to minimize the dust taken in at the back of the grinder.

You turn counter clockwise to loosen it. It might be pretty tight.

you can try going to Makitatools.com and downloading a breakdown for this tool. If it arcing badly at brushes there could be a wiring problem or damage to the armature, check the wiring first and also the wheel spinning off might mean that you are running in reverse. did you take the field out of it and if so it might be in 180 degrees out. Let me know

If the armature is shot, it will spark a lot where the brushes are touching the armature comutator. To remove the armature:1 Remove brushes. 2 Remove 4 screws holding the gear box. 3 Pull away gear box from the body. The armature may come with the gear box or not, it's only pushed in, so you should have no problem to disassemble it. If the armature stay in the grinder, use two skrew drivers to pray it out. You may not see anythink wrong with it, but it may be no good . That's Makita special, they don't make it good as they used to. The price for new grinder is about $130, for armature $65. field $40

Did you check continuity to the field/brush holders. They have a garter spring that sometimes became overheated and broke. It seems like you have done everything else. Let me know