Having trouble diagnosing a wiper problem. I believe I have the 14W Lucas unit although it doesn't have a Lucas mark. Without the blade on the shaft rotates fine. With a wet windshield the blade rotates OK, but as soon as the screen dries even a little the arc rotation is greatly reduced, the speed is very slow, and it doesn't park right. Originally the wiper worked fine even dry. This is a new unit. I'm not fond of Lucas electrics, but replacing it with another brand could be a real problem considering the spatial confines of my SPF. I took the motor apart. No apparent shorting, etc. Any help appreciated.
Lucas wiper motor
- Thread starter SwiftDB4
- Start date
Possibly a bad connection which limits current (amperage) to the motor under higher load when it will try to draw more current.Check connectors,wire size and junctions ALL the way back. Try the motor with direct connections(tempy inline fuse for safety) to a 12vdc source that is known to have more current available than the motor's full load rating,i.e. direct from a battery with large gauge wires.If that works ok,then are you using a Lucas switch?Next thing to look at electrically are the motor brushes.Partial contact reduces current flow. Try letting the motor run a bit(free) if all else looks ok.Also,is there lubricant in the gear reduction and the linkage/arm shaft?
Last edited:
Jim Rosenthal
Supporter
You might also make sure the motor has an adequate current return path, ie ground. If it is not properly grounded, that will limit the current which can flow through the motor, hence limiting the work it can do. You may need a separate grounding lead to achieve this.
It is most likely you have a problem with your cable rather than your motor.
I had the same problem in my road car using Lucas wiper and cable. turned out the wound spring section that creates the rack effect had broken and was allowing the spring to slide up and down on the wire center section. this caused me inconsistent parking as well as variable wipe while in use.
I installed a new cable and all was fixed. I was able to replace it by taking the wiper arms off, disconnecting from the motor and pulling out. putting back i had to rotate the new cable a couple of times to engage the worm then push in to the next one .
I had the same problem in my road car using Lucas wiper and cable. turned out the wound spring section that creates the rack effect had broken and was allowing the spring to slide up and down on the wire center section. this caused me inconsistent parking as well as variable wipe while in use.
I installed a new cable and all was fixed. I was able to replace it by taking the wiper arms off, disconnecting from the motor and pulling out. putting back i had to rotate the new cable a couple of times to engage the worm then push in to the next one .
As briteyes stated, have a good look at the drive cable and spindle unit. The spindles are know to sieze in their housings and this will sufficient to not give you a full sweep over a dry screen
Regards
Andy
Regards
Andy
