Wiper Sweep

[tim hunt]

For some time now I  have been plagued by wiper blades that overrode the screen rubber at the extremes of travel, particularly in heavy rain when the screen was well lubricated. This is even with a replacement rack and wheel boxes. I concluded that I needed a wiper gear and shaft with a smaller sweep than the standard 120 degrees of the DR3A motor fitted to a 4A. I concluded that a 100 degree wheel would be ideal and should give sufficient coverage, at least on the driver's side, taking into account the inevitable extra slop in a rack and pinion system. I looked out for such a wheel, which was difficut to find and the usual suspects seemed to want a king's ransom for such an item when available. 

To  my great surprise and delight I found exactly what I had been looking for at an autojumble last weekend for the princely sum of a fiver! I stripped the motor and fitted the new gear, turned the rack through 180 degs when refitting to the motor and took the opportunity of rotating the wiper spindles 120 degs from their rest position after removal of the rack. On reassembly and test I found the sweep looked very promising. However, the blades no longer self park and coud not be persuaded to do so no matter what position I tried for the limit switch. Hey ho - do one job and make another, but i'm not too bothered since it's no problem to switch the motor off when the blades are in their lowest position.

I am now actually looking foward to the next proper downpour so I can test the system in earnest. - Anyone want a 120 degree wheel in good condition?

Tim 

[rcreweread]

Tim - yes please, as like you, I couldn't justify the high charges the usual suppliers are looking for - I'll PM you

cheers Rich

Edited June 18, 2022 by rcreweread

[RogerH]

Hi Tim,

are you certain that the replacement wheel boxes are for a TR4A and not theTR6 that uses the 14W motor.????

The self Park wiper inside the motor top hat will fit the normal 120' gear but your gear from unknown source may never had a self park and as such the wiper contact does not fit.

Having no self park has a benefit.  With standard set up should the blades seize on the screen then the  self park will continue to supply current and burn out the motor.

 

Roger

[tim hunt]

19 hours ago, RogerH said:

Hi Tim,

are you certain that the replacement wheel boxes are for a TR4A and not theTR6 that uses the 14W motor.????

The self Park wiper inside the motor top hat will fit the normal 120' gear but your gear from unknown source may never had a self park and as such the wiper contact does not fit.

Having no self park has a benefit.  With standard set up should the blades seize on the screen then the  self park will continue to supply current and burn out the motor.

 

Roger

Nothing wrong with the wheel boxes Roger, as for the replacement gear and shaft assembly it is identical to the 120 degree gear I removed, except that it bears the mark 100 and of course the eccentric drive is positioned differently to reduce the sweep. It has the groove in the top of the spindle to accept the wiper and locking circlip exactly as original. I have now tested the wipers with a hose to simulate heavy rain and am very happy with the sweep, sufficient clearance and no more overriding of the screen rubber at extremes of the sweep. I wish I had made the change years ago! Can't face stripping the motor again, I will live with the absence of self parking.