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300Tdi starter motor replacement brushes

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My starter motor, a Bosch unit, is getting very close to needing new brushes.  I have replacements, which I believe are the correct part number, STC1246.  However, on examining my starter the existing brushes appear to have the braided copper strap spot welded to the fixed contacts.  How should I approach separating the braided copper strap attached to the fixed terminal to allow removal of the old brushes.  The new brushes have a clip on the end of the braided copper strap which looks as if it should be crimped onto the fixed terminals.

Many thanks for any and all suggestions.

Mike

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Clip the old braids off just after where they're spot welded, leaving a few mm. Solder the end of the braids on the new brushes to the ends you've left on the contacts and call it job done :)

It'll need a hefty soldering iron and plenty of flux, though. 

 

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A pic would say a thousand words :)

I'm not so sure about using solder so close to where all the heat is generated to be honest...

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Fair comment, but if it gets to 250C where most solder melts you've probably got bigger problems... A fair few old starters I've tinkered with do have solder joints from factory, but spot welding is probably easier and more reliable for manufacture. 

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Yeah, being a land rover, cranking for long periods are a definite possibility ;)

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Thanks for the replies so far.  Here are some photos:

First, a view of the copper strap to one of the old brushes.

DSCN1178.thumb.JPG.ad141a3233a73f84498b9f8008fb0e53.JPG

 

Here is a clever shot of both sides of the connection.

DSCN1182.thumb.JPG.f82f41e84dfc965e88b636d342012a41.JPG

 

Finally, here is a shot of the replacement STC1246, which I believe to be the correct part.

DSCN1180.thumb.JPG.f73d0c8080b695c3c3723848ce68ae4b.JPG

 

The fixed parts that the copper straps attach to appear to be permanently installed with an epoxy(?) compound, not intended to be replaced.

I can't be the first forum member to be replacing 300Tdi starter brushes, so any further thoughts and experience will be much appreciated.

Mike

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They look to me like they will just push over where the current braid is crimped in.

 

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Bowie69,  I agree, provided that would make a good enough and reliable contact, but first I've got to get the old braid off the terminals.  How should I do this?  Perhaps a small die grinder would do the job.  Any other ideas, please?

Mike

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OK, job done.  I used a die grinder with a small cutting disc to separate the copper braid of each brush from its terminal.  I then soldered the new brush clips to the terminals.  The only problem I had was when one of the new brushes hung below the solder terminal and the liquid solder flooded the braid and it set solid.  I remedied this by re-using one of the braids from an old brush.  Starter now rebuilt, refitted and tested successfully.

Mike

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A Solder sucker may have helped de-solder the braids bought one myself recently and it works well only cost about £5

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Hi, 

Yes, I was hopeful, but failed.  The problem of using a solder sucker on braid is that the combination of capilliary action and the texture of the braid makes it very difficult, if not impossible, to get an air-tight connection, and I just kept drawing air into the solder receiver.  It might work on a much coarser braid, such as used in earthing straps, but for the fine threads in the brush braid it was hopeless.  It's not surprising that braid is used as one of the methods of removing solder from soldered connections.

Mike

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