replacing brushes onto motor

[blueb8llz]

hi, my reedy krpton kr motor needs the brushes replaced. i have never done this before and need some help . do i just unscrew it and put in the new one and solder that wire thingy onto the motor?? please help me

thanks all

[gizmoguy303]

Buy some Reedy #766 brushes. Take the springs off (make sure you remember which one was on the positive side and which one was on the negative) and slide the old brushes out of the brush hoods. Unsolder the brush shunts from the hoods.

I highly recommend cutting the comm while replacing your brushes. So, remove the two endbell screws (silver phillips head screws opposite eachother), and slide the endbell off. Pull the armature out of the can while making sure that the shims on the shaft remain in place. Take the shims off, using some organized method of remembering what sides of the shaft they were on, and give the arm to somebody who can cut it for you. :) If they are cutting a lot of comms you might want to write your initials with a sharpie on the green armature stacks.

Reassemble the motor with the shims in the correct place, solder the new brushes onto the hoods, and put the brushes back in with the springs, making sure that the springs are on the right sides.

[ikraj]

I assume that you do not have a comm lathe so do this meanwhile.
Get yourself a set of comm cleaners (at lhs) and skim the comm with them to clean it. Once you do this the comm should be shiny, it will not be perfect but it will be much better than what it is right now.
Do you know how to check for hood alignment. That is one of the most important things in a motor. The better aligned the best performance you will get. This is a MUST. If you do not know how to align them the right way ask...we will help you. You will see how much better your motor will run. I have never seem a motor that comes out of the factory with the hoods aligned...specially stock motors...some mods do a better job...but not perfect. Aligning the brushes will preven excessive arching, you will get higher RPM's, better efficiency and the motor will not get as hot, not to mention that your comm and brushes will last longer.

GOOD LUCK

ikraj

[highroller]

With modified motors before taking things apart do this first. Get a permanate marker, color one endbell retaining screw head and make another corresponding mark on the motor can. This step will help in reassembling motor so it set at the right timing mark and runs in the correct direction. During each step, keep parts of oriented positive brush spring, negative brushes spring, also look at the how brush is installed in brush hood. When loosening endbell screws only unscrew enough to rotate endbell and remove it. Look inside for shims that may come off and inside the motor can for shims that may get stuck inside (lightly tap can against plam of hand on a towel) keep those in the correct order. Inspect the wear comm for wear - if there is extreme wear, in the area where brush rides - it should be trued (deeper grove will be noticeable). For soldering brushes (only Trinity sells brushes with or without eyelets) use a soldering clamping tool (this prevents solder traveling up brush braid making it stiff or hang up). Needle nose or an aligator clip is a good subsitute, leave about a 1/16 -1/8 area exposed, pretin and solder to endbell. Install washers and shim in correct order, install back in can and install endbell, tightening screws just enough to prevent endbell from moving, overtightening may put too much pressure on armature assembley, install brushes then springs. For racing I like high silver brushes but for bashing or conditions where you want less wear use the Reedy 760 brush. For break in I rotate the endbell back to the zero degree mark, then back to the desired timing I use for racing after breakin as been done. By reducing the timing during breakin it reduces arcing and brush doesn't bounce in hoods as much. For oiling bearing I use 3in1 or Marvel Mystery oil, it's much cheaper than RC brands and the Marvel Mystery Oil doesn't have as much drag (low viscosity).

[vegasdrift]

How do you align the hood?

[highroller]

The purpose of aligning the brush hood is so brush aligns properly with each comm segment (which is divided into three sections). To see if hoods are aligned use a old brush or one that not gonna be used, color the face of brush with a marker (to better show how the brush is wearing). Install the the test brushes and run motor for about 30 to 50 seconds or until it shows what direction the brush face is wearing. As long as wear is down the center of each brush face the hoods don't need to be aligned, but if brush face shows wear that off center then brush hood needs to be tweaked in the direction so it does. A couple of companies make alignment tools, forget the 180 degree tools were you supposely align both hoods at the same time, normally you want to align each hood seperately. Racer's Edge, NIftech sells an alignment type bar that can be used with standard size laydown or standup brush hoods. Sometimes all that is needed is a little pressure to move hood, other times the screw or spring post have to be loosen or the holes enlarged to properly align brush hoods. Get the straight metal bar type alignment tool and while you are at it, using modified motors invest in a motor timing guage - this tool is handy to determining what amount of timing the motor is set at plus setting timing that is ideal for your use. Directions usually come with most explaining how to use them correctly. Also if comm has been subjected to excessive wear buy a replacement armature which is less than have the cost of a new complete motor.