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Does anybody replace brushes in starter?

Discussion in 'Tractor/Loader/Backhoes' started by Birdseye, Feb 26, 2021.

  1. Birdseye

    Birdseye Well-Known Member

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    Hi,

    The starter in my Case 580 was sluggish and lazy. Before ordering a new starter, I opened mine up to have a look and see if I could see what’s wrong. As far as I could tell the problem was that 2 of the 4 brushes were shorter than the others and getting hung up in their cages and not pressing against the armature.

    I pulled the spring back and after getting the brushes out of their cage , I sanded the rough spots so that they again slide freely. I could see however that their length is short and their days are numbered, then the starter will fail.

    I also sanded the copper segments on the armature and then put it all back together and reinstalled the starter in the machine. This cleanup and freeing up the stuck brushes made a huge difference , it spun the Diesel engine much faster. After doing this procedure, I wondered if anyone replaces the brushes in their starters or just replace the whole unit , which is what I’ve always done. It seems like replacing brushes would be a lot cheaper but it may be hard to find a source for these and once the brushes are worn other components of the starter may also be soon ready to fail. Anyway , thought I’d ask.

    Thanks.
     
  2. Dave Neubert

    Dave Neubert Senior Member

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    Any rebuilder will replace these and turn the armature There are quite a few in Topeka just look up starter alternator rebuilders
     
    Coy Lancaster likes this.
  3. AllDodge

    AllDodge Senior Member

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    I don't but in most cases the brushes can be found. Just depends if its worth doing

    There is a place near me that rebuilds these kinds of things and I just let them do it. Much cheaper then buying
     
    Coy Lancaster likes this.
  4. Truck Shop

    Truck Shop Senior Member

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    On a high hour starter unless the rebuilder has a torque load test stand to test run and load to amps required, you don't have much. If the armature is getting tired it will not be
    able to take a full load test at lower amps.
     
    DB2 likes this.
  5. Coaldust

    Coaldust Senior Member

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    No, not with common, run-of-the-mill stuff. Rotating electric is highly competitive and easy to purchase. It’s too risky to open a high hour unit and warranty it afterwards.

    Except, I’ve had marine customers hire me to take their Delco starting motors apart annually. Clean, inspect/replace parts as needed. Check no-load amp draw, rpm, pinion, solenoid contacts and pull in/hold in amp draw, paint and install. Test cranking amp draw. This was for a critical application where the engines had to start every time. They even did that with new starters.
     
  6. Birdseye

    Birdseye Well-Known Member

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    Thanks for the reply’s to my question.

    Coaldust, you mentioned that the electric motor market is competitive and that must explain how a new starter weighing 18 lbs is for sale online for $87-$102 , delivered, no core. That seems too cheap for any starter that will function, competition has driven the price down as you say.

    Besides failure to make contact and wear of the brushes that result in sluggish/lazy turning, do other components wear slowly and cause degraded performance ? I’d assume that any other component would either fail 100 percent or work 100 pct, for example a motor winding. Thus, dropping in a new set of brushes may be all that’s required to get another couple of years of service out of a starter.

    There are some vendors of brushes (ex: electricmotorsvc.com ) for motors out there although finding the correct matchup set may not be easy, it seems like a fairly easy fix to replace a set of brushes , even in the field.
     
    Last edited: Feb 27, 2021
  7. DaveA

    DaveA Well-Known Member

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  8. Coaldust

    Coaldust Senior Member

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    Birdseye,

    You asked about other high wear components. The solenoid contacts really takes a beating and the most likely culprit of excessive voltage drop. The contacts can be replaced, rebuilt with silver solder, re-surfaced and the disc can be flipped over or replaced.

    A slow starter might be dragging the armature on the fields windings or poles. That’s something to look for when you have it apart. You can replace bearings, if needed.
     
  9. Welder Dave

    Welder Dave Senior Member

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    Solenoid contacts are a major PIA on Nippondenso starters.
     
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  10. Coaldust

    Coaldust Senior Member

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    Birdseye,

    Can you post a picture of your starter?

    I was thinking about the glorious 80’s and trying to remember what a Delco 40MT sold for. I’m thinking around $500.
    I can pay full retail today at NAPA and get one for $325. Or, go to Kenworth and get a brand new gear-reduction Prestolite for $275 and no core charge. That’s what I usually do. They draw less amps, crank better and are way easier to install.

    it’s funny thinking back that we used to fix that stuff. I remember in school we learned how to rebuild starters and alternators. And those stupid series-parallel switches. Even in high school auto shop, we took Delco 10MTs apart, assembled /tested. Even turned armatures and undercut commutators.

    All that stuck with me and made me a much better troubleshooter.
     
    doublewide likes this.
  11. Swetz

    Swetz Senior Member

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    Coaldust, You started me thinking of all the things that we used to rebuild, and sadly, when you think hard on it, what they have done is shifted all that work to China. We rebuilt all the wheel cylinders for brakes, calipers too. We cut the drums and rotors too. Try to find a garage that cuts drums rotors today. They just call china and get a $25 rotor. For that matter, find an auto parts store that can cut a flywheel any more...gone. Carburetors, were always fun, especially in the 80s when they added solenoids. Then front wheel drive became popular...we were the place to get drive axles rebuilt...now, they all come from china, but not sure how rebuilt they are! The list goes on and on, and who knows at what point it will end!

    And I truly agree that when a technician truly understand how something works, he/she will be much better at their craft...said another way, you are not just a parts changer that keeps changing parts until it is fixed:oops:, by luck that is...LOL
     
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  12. Truck Shop

    Truck Shop Senior Member

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    Or just go buy a 39MT with clock-able nose cone for 300 and be done with it.
     
    Vetech63 likes this.
  13. 56wrench

    56wrench Senior Member

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    colour me cheap, but i usually repair my own starters and alternators if i can get parts for them. some newer ones may not have parts readily available. i can turn the commutator in my lathe. no need to undercut the armature- that's for generators only, which unless you are restoring something, are usually updated with an alternator because generators don't have as much output at lower rpm. armature bushings in each end and in the middle(depending on the particular starter) need to have minimal movement, otherwise the armature will drag against the field coils. the bushings are usually oil-impregnated(oil-lite), therefore a plain brass bushing will not last. on starters with soldered-in brush leads, they can be more difficult to change if you do not have a large soldering-gun or iron. if a starter needs too many parts, it will be cheaper to go with a new or a rebuilt unit but not all are created equal. you usually get what you pay for. it also depends how often you use the machine
     
  14. Coaldust

    Coaldust Senior Member

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    TLDR -warning

    There is so much extra electrical curriculum that needs covered now in school, that I stopped having my class take starters apart. But, I still had them take Delco 10si alternators apart and go through the process of testing and assembly.

    The previous lab time was well spent. It removes the mystery inside the component. They learn about testing diodes, transistors (VR), schematics, capacitors and the theory’s of electro-magnetic principles.

    There is also the intrinsic satisfaction of taking something apart, putting it back together and seeing it work on the test bench. Or, not. It can just as valuable for the learner to see the alternator go up in smoke.

    When designing curriculum, I like to put the electrical classes towards the beginning of the program. So, taking apart alternators were one of the first components they disassembled and got to use their tools and practice Psychomotor skills.

    Whats that mean? Movement, coordination, manipulation, dexterity, grace, strength, speed and so forth. Why?

    We can laugh about that, but many students entering trade programs have no practice using tools. Watching the students fumble and loose springs and other small parts required a lot of patience. The students had to learn patience, too. And accountability.

    I received some crap from my Division Chair and some of the Advisory Board members about “ rebuilding” alternators. Some of them got it when I explained the
    Cognitive theory behind my madness.
     
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  15. Coaldust

    Coaldust Senior Member

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    Truck Shop,

    Good choice. Nothing wrong with a 39MT. A couple pounds lighter than a prestolite m110603.

    Don’t have a core to deal with the Prestolite.
     
  16. Tyler d4c

    Tyler d4c Senior Member

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    This gave me a laugh when I was a little kid I was always looking for something to rip apart. They never got put together after but was good fun for a 6 year old me
     
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  17. Swetz

    Swetz Senior Member

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    I design training for a Gas and Electric utility. We must show the new students what a
    flat head screwdriver vs Philips screwdriver (they call them the plus and minus screwdriver...LOL). Obviously, if they have never seen them before, they have never used them before. Pipe wrench, what's that!! And the righty tighty is unknown as well. To me it is a shame that we have a generation of students that do not have the slightest knowledge about technical skills!

    Tyler, You reminded me of the first time I "worked on" a lawnmower. I was just a young kid and my neighbor threw it out...well, I was going to fix it, so I started pulling it apart (had no idea what was wrong with it of course). Of course it never ran, but I can still see those valves from that flat head engine in my mind...I would say I learned! Funny ending to the story...the owner of the lawnmower told me that I could never fix it because the sparkplug hole was stripped...LOL good thing we tore the whole engine apart huh!
     
  18. Tyler d4c

    Tyler d4c Senior Member

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    Someone expressed there concern to my mother to make sure I didn't sneak any tool on the schools bus when I stated school so I wouldn't take the bus apart for crying out loud
     
  19. TVA

    TVA Senior Member

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    I do rebuilds on starters and alternators if time permits unless windings obviously burned out.
    Found out in the hard way that cheaper replacements you get online, and not so
    cheap ones from dealers is not the same quality.

    I don’t like the idea of giving my American or Japanese build high quality components, and get some Chinese knock off back. The matter is in the materials used to build the components, not how good the Chinese could copy the manufacturing.

    Replacement electrical components do not perform or last the same as original ones.

    But, there’s always the chance that winding insulation is started to fail on your original ones also.

    if the starter had oil leaking on it and brushes was soaked in it - brushes will go bad really quick.
     
  20. Coaldust

    Coaldust Senior Member

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    The last, old school, auto-electric shop just closed the doors in Anchorage. You know the type. Walk in with a crusty relay from a 1971 whatever and they just happen to have a exact NoS copy sitting on a shelf.

    Call them with a request for a 36v Delco 50MT, ask me a couple questions, and the old fella in the back would have the correct pinion and nose cone installed and clocked, boxed and waiting for me before I arrived in will call.

    Hate to see them go.
     
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