Date: Fri, 7 Mar 2014 06:30:44 -0800
Reply-To: Poppie Jagersand <poppie.jagersand@YAHOO.CA>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Poppie Jagersand <poppie.jagersand@YAHOO.CA>
Subject: Re: Starter Motor Internal + Strap Replace?
In-Reply-To: <CAB2RwfiR=FkdNYeFOiKF7DCy2i=OUtMxnz1hcvJKtynV7d6QUA@mail.gmail.com>
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> On Tuesday, March 4, 2014 1:26:30 PM, Neil N <musomuso@GMAIL.COM> wrote:
> Hi all.
>
> This starter worked fine until the positive strap from inside starter
> to solenoid, failed. I suspect that if I replace the part shown below,
> the starter should be ok as an emergency spare.
https://lh4.googleusercontent.com/-zKO1TlMtrtY/UxY0aA2t2ZI/AAAAAAAAI5A/u4BuSmQ_3Xg/s512/%252B%2520buss%2520strap%2520on%2520%252788%2520starter.jpg
M: I have done that repair. First I carefully drilled out the old strap from the starter motor stator assembly. I choose the drill size to maximize the hole size, while not drilling out too much so that the two sides of the stator connection separates. Hence I had a clean round hole.
Then I fitted a new multistranded copperwire and soldered it in. I used fine stranded wire that started out slightly larger in diameter and removed strands until I got a tight fit. Then I soldered it in. Covered the exposed wire with shrink wrap. Suitable wire can be bought from e.g RC hobby stores or Audio stores (thick speaker wire).
On soldering: I use regular solder. The key is to minimize resistance
(since it is the resistance that causes heat). To minimize resistance
means maximizing contact area. Hence the precise fitting of the wire
above.
NB: DC motors of this type are not designed to run over 100C. Regular solder melts over 300C.
> All 4 brushes appear close in length: ~ 20 mm. Would this possibly
> indicate that the starter has seen low usage?
image: https://lh3.googleusercontent.com/-a_2SBL1kln0/UxY0aLVMv3I/AAAAAAAAI44/zqMFSrVFDQI/s576/%252788%2520starter%2520brush%2520%257E%252020%2520mm.jpg
M: Your commutator is all black from dirt or sparking. Try to clean it with some isopropyl alcohol. Inspect it. It may be pitted too. I've sometimes made the mistake of putting too much grease in the rear bushing. That has then caused the commutator to become dirty. When the commutator is dirty the brushes make poor contact.
Your brushes look short in the picture. When judging brush wear put the brush holder on the commutator and see how much further the brushes can move before it gets hung on the wire braid.
For brushes it is possible to get two types: One type has just the wire braid. The better type terminates the wire braid with a small copper plate. The copper plate can easily be soldered to the brush holder so that the solder contact area is way more than the braid crossection area, hence eliminating heat buildup in the solder joint.
NB: A professional autoelectric rebuilder uses an electric spot welder to attach the brushes. However these are expensive pieces of equipment (over $1000). Some will do small jobs like just the welding, but I find that ,most these days won't. Many have switched to selling off the shelf rebuilts or aftermarket replacements. That way they make $100 by just taking a product off the shelf, while actually doing the rebuild will take a couple of hours and net them maybe $150.
It is also possible to buy the brush holder with brushes. New brush holder assemblies come with a cardboard tube inserted to separate the brushes and make it easy to slip the brush assembly over the commutator. In DIY work I instead use a suitable size socket.
Martin (and 82 Westy 1.9TD Poppie and '85 Westy 1.9 gas Popul)
http://www.cs.rochester.edu/u/jag/vw/
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