Stuck electrical brushes

[Left Coast Chris]

I have a 5402-A old Makita beam saw that I found on Craigs list.

The guy said it ran and could saw beams as is.   After getting it home I plugged it in and it did run.   After starting it several times, it started having intermitant power cut offs.   

I first checked the cord then took the handle apart and tested the trigger switch.  All O.K..

It had a rusty blade so it was obvious that it was sitting for awhile so I checked the brushes.  After removing the brush inspection screw plates the springs with brass contact plate elongated and have a copper line imbeded into the carbon element.  Lightly pulling on the copper line did not budge the brushes.  Pushing on them did not move them either.  They are frozen in the sockets.  I cannot see inside the housing very much so I assume the sockets are aluminum like the body.  The sockets may be brass also since the outer part of the socket where the spring is shows brass.

I went to the hardware store and bought some spray electrical cleaner which is ether or similar very light solvent that evaporates very fast.  I also bought some liquid wrench in the blue can which is a penetrating oil.  For one day I sprayed in the electrical cleaner and the brushes did not free up.  The second day I alternated the liquid wrench and electrical cleaner and one of the burshed appeared to push in slightly with a little pressure from a small screw driver.  It  would not move in the pull direction but I hesitate to pull very hard. 

I did order some rust reaper.  Not sure it is good around electrical components or if it will tackle aluminum corrosion.

Anyone solve this one before?  Any advise? I am being patient and will give it time to try the solvent to avoid removing the armature and/or using more drastic measures to free the brushes.

[Mike_P.]

Chris:

We shipped your RR on Monday (11/30/09).  You should not have a problem with it around electrical components and it should work well with aluminum and/or dissimilar metal corrosion.

An electrical contractor in Florida was using it on outside lights to free up connections.

Let us know how it works out.  Thanks for the order.

Mike

[Left Coast Chris]

Hi Mike,

Thanks for the Rust Reaper shipment.   It is the first time Ive used it and I can say that it is the best stuck parts liquid I have ever used.   When taking apart the old Makita Beam saw I was really affraid of breaking off some screws and loosing the saw.   Several screws were stuck and Rust Reaper freed them up.  Good stuff.

Regarding the stuck brushes, the reason they were stuck is a real mystery.   After extensive soaking with everything on the shelf  (even Rust Reaper) they would not come loose in their sockets.  I ended up pulling out the armature and busting out the old brushes.  The sockets are solid brass and after breaking them out there was a black stain on the brass.  Im guessing that the guy that sold me the saw put something on them that made them swell or maybe salt air (?).   The new brushes went in fine and were free without much cleaning of the sockets.   Strange, but it turned out in the end.   The saw works fine and Im really glad I had the Rust Reaper for the stuck screws.   

--Chris--

[Mike_P.]

Chris:

Glad that the Rust Reaper worked on the screws.  I hadn't thought about the brushes swelling. 

Thanks for letting me know.

Mike