Guest DiscoTD4 Posted April 30, 2008 Share Posted April 30, 2008 I am submitting this in order it may help any other Discovery owners: I have recently replaced the starter motor brushes on my 44k 97 TD300. It's supposed to be a Bosch starter motor, but I suspect may be a pattern replacement, for reasons below. Before delving in a number of checks were carried out before condemning the starter motor: Replaced battery with known good batteries which failed to improve situation Checked / cleaned up starter motor to earth connection which failed to improve situation Checked / cleaned up starter motor 12v supply connection which failed to improve situation Checked and charged battery which failed to improve situation Performed a voltage drop test – noting the battery voltage when starting – which was around 10 – 11v All the above came back clear so I was confident the root cause would be the starter motor - which it was. Upon stripping I found the bearings/bushes were bone dry, the commutator was badly scored and the brushes severely worn at an angle. Closer inspection showed that the brush holders are very sloppy fit and allow the brushes to lean at an angle against the armature, as a result of the spring tension against them. Because of this design flaw I suspect this may be a pattern replacement starter motor, rather than a Bosch. In order to reduce the leaning affect I had to pack out the top of the brush holders with some plastic shims, in order to get them at a right angle to the commutator. I have skimmed the commutator as much as I dared, replaced the brushes by re-soldering the crimp ends that come on the new ones and done a thorough greasing all round and she seems as good as new now. Total outlay was £17 for the new brushes from LR Series. Quote Link to comment Share on other sites More sharing options...
sotal Posted April 30, 2008 Share Posted April 30, 2008 I recently took mine off for reconditioning (which cost £20 at the local Auto Electricians) Mine was a Bosch Motor, it was black and had bosch stamped in the side, if that helps you to know if yours was bosch or not. Most of the pattern ones I have seen are silver or gold Quote Link to comment Share on other sites More sharing options...
Guest DiscoTD4 Posted April 30, 2008 Share Posted April 30, 2008 For £20 that's fantastic value, it took me a couple of hours to do the overhaul. Regards Quote Link to comment Share on other sites More sharing options...
sotal Posted April 30, 2008 Share Posted April 30, 2008 To be fair he didn't need to do as much as you did, he stripped it down and said it was in near mint condition, just found a bit of play in the com bush, so he replaced that and put it back together Quote Link to comment Share on other sites More sharing options...
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