Is there any trick in replacing the carbon brushes in the cap? I don’t want to break something trying. I’ve got some new brushes. I only get to see this tractor once a week so I thought I’d try to replace the brushes this weekend. Thanks, Craig

The brushes are held in with and attached to a spring. I don't remember the direction of the helix, but turn them so as to wind the spring up and gently pull them out with the spring attached. They will go back in a similar way

Thanks, Stephen, for the reply. The brushes that I bought From MacDonald Carb have a spring that is wound with a slightly larger OD on the first 2 loops (the end not directly attached to the brush) of the helix. The loops are larger than the receptacle openings inside the cap. The rest of the coil loops look small enough to not bind once in place. Obviously the springs are designed this way to friction lock them into place. No doubt there is a procedure so that the spring doesn’t get misshapen or kinked when it is pushed into place.

I wrote MacDonald but have not heard back.

I heard back from McDonald Carb with the following instructions:

“You have to turn and push gently in the direction the spring is wound until fully inserted. The larger coil is to retain the brush in the cap after installed. If you just can't seem to get it, you could use some pliers and close up the large coil slightly. Be careful not to collapse it if you do this.”

In my case I had to push the the brush down gently (patiently) until the spring was nearly collapsed and gently twist clockwise. All three went right in! Yay!

Glad you got it together.