7 replies to this topic

[roblightbody]

Hi all,

 

Hoping you can help speed me up with diagnosing what bits probably need replaced on my 1990 Cooper.

 

When I first turn the wipers on, they seem reluctant to move far at all - they sit comically high above the bottom of the screen, and go nowhere near the drivers side either and you have to use screenwash to help them along.  After a few minutes in the rain, they end up banging heavily into the bottom of the screen - almost slapping the scuttle - and also go off the drivers side of the window past the rubber seal!  

 

In the distant past - 10 years and 25 years ago - I have completely dismantled and reassembled the mechanism with the motor out of the car, but what is it most likely to be - the wheel boxes, the wiper rack or what?   Or do I just replace both anyway... parts are relatively cheap vs the hassle factor!

 

Many thanks,

 

- Rob

Edited by roblightbody, 02 July 2020 - 07:59 AM.

[InnoCooperExport]

Is the alignment of the wiper arms on the wheel boxes correct relative to the "stroke" of the motor? I would think about removing the cover from the motor and the arms from the wheelboxes. Then turn the motor until you are at the bottom of the stroke (where the pin connecting the flexible worm is at it furthest from the opening, so around 3 or 4 o'clock position from memory), when you find that point refit the wiper at the bottom of the window. That should stop them coming off the window at the bottom and smacking into the rubbers at least. 

[nicklouse]

If original then sounds like the wheel boxes are lose or worn. Also everything might need some lubrication.

[timmy850]

I'd recommend some Rainex or similar on the windscreen. It reduces the need to use the wipers, and it also reduces the friction on the wipers and allows them to sweet better when it's dry. 

[GraemeC]

Wear in the wheelboxes and, to a lesser extent, the rack connections in the motor (both ends of the con-rod).
 

I would put money on you being able to move the wipers about 10-15 degrees by hand without feeling any resistance - this is slop in the system.  Running wipers on a dry screen accelerates the wear, but it will always happen and after 30 years it isn't surprising.

 

The reason they overshoot is that, once there is lubrication the momentum allows the wipers to go to the extremes of the wear in each direction - if you look really carefully you may notice there is a slight pause at either end of the travel as the linkage catches up again. (That is unless someone has fitted a replacement motor or drive gear that has the wrong sweep angle).

[roblightbody]

Thank you for the replies!

 

I'll let you know how I get on.  I've actually found a new unused wiper rack in my box of spares but am going to order new wheelboxes too and just do the lot.

[Ethel]

Hold one arm still and feel for play with the other at various angles of their travel, that'll help diagnose if it's at the motor or in one or both wheel boxes, or a particular section of the rack. Odds all of it will be less than perfect though.

[sonscar]

All the comics used to recommend dismantling the wheelbox and reassemble the gear 180 degrees rotated,free to do if you have the time,might improve it.Steve..