wipers issue

[droptheengineout]

Hey all,
I have a '48/'49 split screen.
I'm having a bit of an issue with my wipers, and I'm not sure how to debug it. The motor is working fine and the wipers move, but it seems it only takes the slightest resistance on the wiper ams to hold the wipers still, so much so that the friction on the glass is pretty much all it takes. If i feel the motor mounting (brand new) while the wipers are on, I can feel the whole thing rocking significantly on its rubber feet. So basically, I'm not sure if:

The 2 wiper wheelboxes are slipping on the drive cable, (although if you hold one arm, both stop)
or
the rocking of the motor on its rubber feet is enough to compensate for the rotation of the wheelboxes,
or some other issue I havent yet thought of.

I'm not sure how to address this issue.

Any help appreciated!

[Bally]

G,day
The first thing to do is to eliminate the motor rocking. How did you mount the wiper? The correct proceedure is to ensure that the triangular mounting is secured to the wiper by two screws. Then screw the three 1/4"bsf nuts till they just touch the rubber. Then put the assembly into its mounting plate and secure with three more 1/4 bsf nuts and spring washers. If this is done then I cannot see how the motor would rock. If the assembly has been correctly mounted and a load on one arm stops both arms then it would be very unlikely that the wiper boxes would slip on the cable. If this is so then I would suggest that for some reason the motor has very limited power.
Cheers Bob

[Bally]

G'day
The original wiper mount on my car had 1/4" bsf mounting studs. However on the spare wiper I have which has a new mount from ESM the stud diameter is 0.233 inch which would be O BA. It would be wise to check the thread to ensure you have the correct nuts.
Cheers Bob

[John Ballard]

I have recently rebuilt my wipers, slightly different to yours mine being a Minor 1000, but the greatest cause of resistance to mine was the wheel boxes. over the years water gets in and rusts the drive shafts making them stick inside.
I replaced mine with a good second hand set lubricated well and I sealed as much as possible with silicone where they protrude through to the wiper arms. Of course I dismantled the drive cables cleaned and lubricated as well.
The run very well now.

[Bally]

G’day John
I agree that the wheel boxes should be clean and rust free and well lubricated. I have removed mine and cleaned them and repacked with grease. A quick way to check for tightness is to remove the gearbox cover off the motor and lift out the connecting link between the crank and drive rack and manually move the rack to see if it is free. Even if free it still would be wise to remove the wheel box covers and pack more grease into them. If all seems OK and the problem still exists then I would be checking the current drawn by the motor. For a CR motor this should be between 1.75 and 3.0 amps, cold motor and 2 blades on a wet screen.
Cheers Bob

[John Ballard]

I also found I had a low voltage under load at the wiper down to 11 volts so I ran a new earth/negative from the wiper to a good earth near the battery through a relay activated by the wiper switch. I then found I had 12Volts at the wiper even under load.

[grant69]

A tip for wheel boxes is to use DC4 dow corning to seal the shafts to help inhibit water ingress, It can also be used on all electrical connections for the same reason