Notes On Wiper Motor Repairs

[vwnate1@juno.com]

 I'm currently making one serviceable wiper ay. out of two
motor/transmission ay.'s , I have gotten one motor to run well and hope
to start on the transmission soon .

Several people have told me they removed the gearbox cover , saw nothing
wrong and so packed in a bit more new grease  , assuming all is O.K. -
this is NOT SO ! there are bearings in the motor proper which must be
periodically cleaned and lubricated  .

 I found my motor to be in good shape in spite of both bearings
(bushings,really) being completely dry , and the commutator was dead
black , thus preventing the brushes from passing any current , hence it
hadn't drawn even a spark when I tested it . I cleaned the commutator
with aerosol electro-contact cleaner and a rag , as the surface was
pretty smooth , it was soon shiny copper colored as it should be , I
dismounted the brush holders and cleaned the built up crud off with an
old toothbrush , wiped clean the bushings of all traces of old , hard
grease - this is very important , removing ALL the old grease before
packing in with new . 

The primary (smaller) drive gear has two sealed bearings on it and one of
them was siezed so I used one from the other gearbox , packing liberally
with high - temp. moly disc brake bearing grease , the whole thing went
to-gether very easily apart from being carefull to not mix the various
screws up , they look the same at a glance but are in fact slightly
different . the motor will run in either direction but is only correct in
one , as it spins noticeably faster when correctly wired . I also
accidentally installed one brush backwards , this slowed the motor down a
bit untill I removed and flipped it - the brushes wear in an arc , so
when you remove the brushes and holder ay. , lay the various parts out
carefully so you won't make this same mistake as it's not really apparent
to the untrained eye . the brush holder ay. comprises numerous small
parts so be carefull and work close to a neutral surface as you will
likely drop some bits and you don't want them to bounce of into
never-never land .  

 When testing the motor , make notice that it is externally grounded so
it won't work unless BOTH wires are connected . 

 There is also a thin rubber pad that mounts between the motor and the
body , this is important to replace , if it's crumbly , make one out of
an inner tube or other scrap rubber 

 I see there is a rubber water seal where the wiper shafts pass through
the body , I will experiment with O - rings and / or silicone sealant ,
plus check availability of the original grommets as this wipter system is
the same as used on numerous B.M.C. products , it should be available .

 The shop manual makes comment of a temperature operated circut breaker
but I could not find any trace of it .

There appears to be no park mechanism or circut (?) . 

   -Nate