6. Restoring an oil pump
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This circular scoring of the lower body is common - it is caused by bits of steel swarf caught in the bottom of the pump which are dragged round by the rotor |
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The body can be reclaimed by lapping it on a sheet of fine wet & dry paper (400 grade) on a flat solid surface - lubricate the paper with paraffin and use a mixture of circular and straight movements applying even downward pressure.... |
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..... after 2 minutes, inspect and wash the paper out in paraffin to remove the aluminium paste..... |
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.... another 2 minutes of lapping and the marks on the wide web and round the outside have gone ........ |
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..... another 2 minutes and it's as good as new! |
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Checking the clearance of the new outer rotor in the upper body using a feeler gauge - this must not exceed 10 thou - here it is only 4 thou.... |
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Checking the rotor clearance in position 1 - must not exceed 6 thou - here I can't get a 2 thou feeler in. |
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Checking the rotor clearance in position 2 - must not exceed 6 thou - I still can't get a 2 thou feeler in! |
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Checking the end clearance of the rotors - must not exceed 5 thou - here it is just 2 thou. |
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Coat the inner rotor with Vaseline - this will aid pump priming on first start up. |
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Rub any excess into the gaps - no need to pack it solid! |
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Bolt the two halves of the body together.... |
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insert drive dog into the top of the pump with a little oil to hold it
tightly in place ready for fitting. Rotate the dog to ensure that the pump
is free and doesn't bind.
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