Stuart,
Since you have changed the lubricants and replaced the brushes, it
sounds as though the mechanicals are working OK. If you remove the cover
and try to spin the armature with a finger, that would be a test for
mechanical lack of binding, and I suspect that it would be OK there too.
The electric wire to the wipers can be a culprit. The OEM wire was a
larger wire gauge than the modern repro wire is. Should you have the new
wire, it may not be able to carry the current necessary to run the motor.
The little thing will pull down the ammeter noticably when it's running.
You might try jumping a pair of wires directly from battery to the motor
to test again. I've seen cars that use 16 ga "lamp wire" for the wiper
power. A piece of grey shrink-wrap is slipped over the wire where it it
exposed between cowling and windscreen.
It's not unknown for the armatures to fail and to need rewinding.
Someone in your club may know a service center for them. If you don't
score there, I believe that Hal Kramer rewinds armatures. He repairs
clocks, by the way, so if you need timekeeping, call him.
Bob
On Tue, 30 May 2000 19:08:50 -0400 Stuart Keen <simbafish@home.com>
writes:
> On a recent jaunt with my TD (2,891 miles!), I was forced to use my
> wipers for the first time in actual stormy conditions. Usually with
> Rain-X on the windscreen, wipers are not necessary, but because of
> mud
> being flung up by passing trucks, wipers had to be used.
>
> After about two cycles, they quit. Nice being able to rotate the
> wipers
> by hand (try that in a modern car), but I'd like to get the wipers
> back
> to a fully operating condition.
>
> I find they will cycle, but have very little torque and if manually
> stopped, will not restart. I have lubricated, repacked the gears
> with
> high temp grease, cleaned the armature, checked the brushes, etc.,
> all
> to no avail. I even straightened out the connecting rod between the
> two
> wipers (it was bent), but this did not help.
>
> When the wipers are cycling, if I manually stop them mid way, they
> just
> sit there (and would eventually burn up the armature or blow a
> fuse).
> When the wipers are away from the bottom of the arc, there seems to
> be
> more torque, at least if I manually stop the wiper there, they will
> start up again immediately. But not so when at the bottom of the
> arc.
>
> Since I have no experience with TD wipers, I do not know what is
> "normal" torque. I am even thinking that the new wiper arms from
> Moss
> may be exerting too strong of a force on the windscreen and thus
> excessive dragging. Has anyone any experience with wipers and
> solutions?
>
>
> Stu Keen
> 1951 MGTD MkII
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