Uneven running in the rain

[Pip the unready]

Just to let you know of a strange problem I encountered a few weeks ago during that rainy period of June.After an hour or so motoring in the rain my convertible began to run quite roughly and stalled a couple of times at roundabouts. I pulled into a layby, switched off the wipers and the car ran perfectly.If I switched them back on it hesitated.Back home I plugged in an amp meter and turned on the wipers. At one point in their cycle an almost dead short showed -30 on the gauge,it then performed normally until the same point was reached again.The car would splutter or stall at this point.on stripping the unit I found the end float in the wiper motor was such that one of the worn brushes was riding up onto the main wires to the windings as the armature moved back and forth. The metal brush carrier burned and black.I know the ignition doesn't take power through that fuse,but a short of that kind can't be good for it.Anyway a second hand armature with new brushes has cured the problem so far despite a typical British summer and over1500 miles since.

[panky]

Good spot and nice to hear your convertible is not just used on sunny days

[bmcecosse]

Well done ! And what an unusual failure - a 'first' for the board I think!!

[mogbob]

Glad that the new armature and brushes set got you mobile again.

I take it that you reset the correct armature end float , on the adjusting screw to .008 to .012 inch ( .203 to .305 mm ) to cut out the slop and to prevent it happening again ,on reassembly ?
Apologies , if I'm teaching you to suck eggs. Writing for the record , newbies to the site might be unaware of the need for the correct end float. Too tight or too loose can be a problem.
Bob

[Pip the unready]

Thanks for that advice on end float,I might have set it a bit tight,will recheck. All knowledge is good knowledge. Cheers. Pip.