Getting the last drop out of brushes

[Bob Kelly III]

Thanks 5Twins ! I wondered what the size was LOL...Now I know !
......
Bob........

 

[fredintoon]

Well, it's just unnerving to pay $15 for something that's worth maybe fifty cents. I'd like to find generic ones at their actual value and pay myself $30/hr to sand a couple of pairs down. Hell I might even McGyver some lugs from a coffee can lid.....

Hi xjwmx,
nah, that set of brushes has to cost at least $1:50.
The rest of the $15 pays for some guy to buy 'em in bulk, keep 'em in his warehouse
and list 'em in his catalog so you can order 'em.

 

[jonesey]

Now here's a story that will make U all reel back in horror. Pin your ears back Mc Gyver fans.
I have an old workshop electric drill, it must be about 40 years old + a while ago i needed brushes for this old thing and went to my local Bosh agent, nothing. The agent directed me to an electrical repair shop. No problem said the old guy there.
Now his shop is one of those one room places that is mostly W/shop with a counter next to the door so i could see everything he did. He took my old brushes and pulled the wire out of the carbon, he then made two carbon brushes from a much larger brush, drilled a 1mm hole in the ends of them, then holding the brush wire with a pliers against the spring pressure super glued the wire into the newly made brush. That'll be 20 Rands (thats about 25 cents US) he said. will that work said i, yes he said give it a tug and it was really tight. the upshot is the Drill is still working.
Yes plain common superglue. I've done it myself on an old Columbus floor polisher and yes it works.
As yet i have'nt tried it on the XS brushes as you need that reliability but as an Absolute get U home dodge it would probably work. will try it one day.
Out of Africa, as they say.

 

[Paul Sutton]

Jonesey, I had the same sort of experience in India. I visited a small street with about 600 small businesses. You could get anything done there for next to nothing. If you wanted an alternator rewound it could pass through perhaps 4 different businesses with each doing their own specialty e.g. bearings, stator, rotor and repaint. In the western world we cannot even match their prices if we do it ourself.

Just looking into replacing my brushes. There are threads on this forum about taking similar sized brushes and resoldering the fittings. In my searching yesterday I found there is a standard universal motor brush with dimensions 5mm x 5mm x 15mm available on Ebay UK and cost £3.50 including postage for a pair. The spring and wire braid length is correct to fit when soldered to the original SH brush fittings. My SH brushes currently measure 5mm x 4.5mm so I may need to carefully sand off approximately 0.25mm from two sides??

 

[Bob Kelly III]

Jonesey ! Thank you very VERY Much ! I was all set to make my own brushes but didn't know How to hold the wire to the carbon !
you solved that problem for me ! ..... I have drills and grinders that all need brushes Not to mention the XS650 , Now I'll just find an electrical shop and buy a couple of Large brushes and re work them as needed !
Your a life saver !!!! THANK YOU !!!!
.....
Bob.......

 

[Bob Kelly III]

Paul, I know from experience brushes ware in their dimentions so I bet ya the 5mmx5mm will fit perfectly and snugly
try them for fit first and touch them up a bit with sandpaper if they are too snug to slide with the spring itself....
...

.... and they appear to have the perfect size - 5mm x 5mm square x 15mm long. $2.97 a pair.

.....how can you go wrong there eh ???
....Bob.....

 

[Bob Kelly III]

well, I ordered 10 brushes 4x4x14 in size...( hope their big enough for $1.80 and should be here by the end of the month
we'll see then I guess !
I pulled the brushes in the xs650 this evening and they look SHORT ! certainly not 10mm long more like 1/4"
we shall see what that brings they may be too small I dunno but I guess I'll find out !
......
Bob........

 

[5twins]

Why don't you measure them instead of wild guessing? Go to HF and get one of these, probably the best $3 any bike owner could ever spend .....

https://www.harborfreight.com/6-inch-utility-caliper-7914.html

Also, if they're originals, there should be a wear line etched in the side .....

 

[TwoManyXS1Bs]

More brush trivia halfway through this thread:

http://www.xs650.com/threads/dead-rotor-best-options-to-fix-replace.36211/

 

[Bob Kelly III]

Cuz I didn't have a decent measuring device..... but NOW I do !!!!! just bought a digital caliper fer $12.00 at autozone today
I'll pull the brushes tonight and see how they stack up.....
I couldn't pass up the 10 brushes for $1.89.... I can always use them on the hand held grinder ! and drills......
..... got the water-pump replaced in my truck so it's working properly now,
it was another hot one here today !..... I dunno about you guys but I'm ready for some cooler weather HAHAHAHA!
.....
Bob........

....

 

[Bob Kelly III]

Very Interesting.... My brushes measure 4.5MM x5.2MM ( or something like that, they were not square ) and 8.3MM long ...about 1/16" from the ware line ! LOL
looks like I caught it in time .... JUST BARELY !!!! really glad I checked it ! .... at last check it was still charging the usual Low voltage but in the 13v range. this bike only has 7k miles on it going on 8k...... so if you have a low milage machine you might consider checking your alternator brushes too ......as I believe most of the miles on this bike were done at less than freeway speeds on back roads.
I think I will invest in a LED brake light to help get the volts up and clean the slip rings .
.....
so the brushes I bought may or may not work..... I'll see what they look like when they come and if they look too sloppy I'll get different ones !
......
Bob.........

 

[Paul Sutton]

I now have my universal motor brushes and studied then carefully:

1. The originals are better machined and finished - But I expected this.
2. 5mm x 5mm was actually 4.8mm x 4.8mm approximately.
3. Brushes would not fit until lightly sanded to give 4.8mm x 4.5mm (4.6mm was a bit tight)
4. The spring on the new brushes in 5mm OD and will not fit smoothly. The original is approximately 4.6mm OD.

On the new brushes I used the original stock springs due to their narrower profile and the original end fittings. I also drilled holes (1.5mm) in the end fittings as suggested above by XSLeo - Very clever move! The tricky bit is holding the spring compressed while you try not to burn your fingers soldering. But there is an easier way:

Just pass the braided copper wire through one or two turns of the spring as shown above and then make the solder connection. Then wind the spring on the rest of the way.

The finished product is a little more compressed than the original but his should not be an issue because it all gets compressed when fitted. Now for the maths exercise:

1. The depth of the brush assembly to the copper rings is approximately 23.5mm (XS SH).
2. The length of the new brush assembly is approximately 31mm.
3. The maximum allowed brush wear is going to be 31 - 23.5 = 7.5mm
4. Realistically I could go for 6mm of wear before replacement which corresponds to changing the brushes when their length is down to 9mm.

Seems fine by way of thinking.

 

[xjwmx]

Another way to deal with the spring while soldering to the holder. Compress the spring and hold it there with needle nose pliers on the copper wire. Wrap a rubber band around the handle of the pliers to hold it while you solder.

 

[Bob Kelly III]

Very good tips there guys ! thanks ! I like Paul's method as it's a no brainer ! it's like ...why didn't I think of that ??? LOL
I have no idea how critical the fit is of the brushes is but I am guessing it's not that bad as long as their is easy movement....
however if the brushes are too small in size they might cock sideways and jam up and not move at all.....bad news !
the spring MUST be able to go in the brush holder easy so using the original springs was the best way to go Paul !
..... the extra rubber band around the Needle nose plyers trick..... is always a big help I have a bag of big rubberbands in the desk just for that purpose ! LOL
I am thinking of adding a layer of super glue to the top half of the small brushes I bought to build up the width a bit and make those 4x4x14 brushes fit better....
out of all the brushes on e-bay I never did see a brush the correct size so getting ones a tad larger is probably the best bet !
i'll let ya know how they work , good or bad once they arrive.
.....
Bob........

 

[xjwmx]

^When I made mine I didn't pay much attention to the size. What do your old ones measure, since somebody said 5x5 is too wide to fit? Already time to upgrade your new calipers to a dial or digital model

 

[Paul Sutton]

I reported that my new brushes at 4.8mm x 4.8mm would not fit. I just measured the old brushes I removed today, using my new digital calipers, and got 4.92mm x 4.44mm. In Entry 31 above Bob Kelly III also reported his brushes as not being square. Thankfully the brushes are very easy to sand down a bit.

 

[XSLeo]

Easy to sand, but that black dust gets everywhere.
Another trick to hold the wire while soldering is forceps. I have several sets in different sizes. They work good for removing hooks in toothy fish.
Easy to find, even Wal Mart has them in the with the fishing stuff.
Leo

 

[Paul Sutton]

Too my surprise there was no dust issue with sanding the brushes. I used a 240 Grit paper and the dust just collected between the grits. To remove 0.25mm only took 3 wipes of about 50mm along the paper. I then gave the paper a tap over the bin and the dust all fell out. I expected the dust to go on my hands and then transfer everywhere, but this did not happen.

The new brushes did not seem any softer than the originals when I tested them with a knife. My only doubt about the new brushes is whether or not the braided copper wire will be thick enough, but they are not insulated so loose heat quickly. All the rotor current passes through this braid (Maximum current 14.5/5 = 3A Approx.). The springs do not carry current because they are insulated/isolated by the small rectangular phenolic boards.

Edit 4 April 2018: Brushes still fine. Searching Ebay for "VALEO ALTERNATOR BRUSHES 4.6MM X 6.4MM X 14.5MM" gives a brush with a heavier copper braid. These would be my next choice even though they require sanding to 6.4mm down to 4.9mm. But, sanding is very easy with 240 grit paper. Then solder to the original brackets + spring.

 

[Bob Kelly III]

if the wires fail you can put in heavier braided wire fairly easy just drill out the old wire with a tiny drill and fold the new wire over at the end and stuff it in the hole and then secure it with a drop of crazy glue , like the guy in Africa said !
..... I never knew that so it went down in memory !!!!!! LOL
.....
Bob......

 

[Bob Kelly III]

My bag of tiny brushes arrived... they sure look small to me ! so I haven't bothered trying to put them in...instead I ordered some 4x5x14mm brushes for .99 on ebay.... now I get to wait for the slow boat from china again ! LOL
.....
Bob....