Wiper matters

The great British climate gave me cause to test my 289's wiper system a fair bit over the Silverstone weekend, which revealed two issues.  

Firstly, my super-expensive 2SJ washer bottle, whilst producing the requisite whizzing sound, was not depositing any water on the screen.  Given that the driving gods were doing that for me, it was not a huge drawback, but would need investigating.

Secondly, my wipers were working correctly but something was clearly not right.  I have the original 6-wire 2-speed Lucas DR3 motor, with reverse-park operated by an original PRS7 switch.  From the park position, the wipers popped up and swept an arc of slightly less than 90°, which was vaguely reminiscent of my ancient Land Rover's glass-cleaning ability.  I had thought that I'd fitted a 120° gear in the motor but it seemed not.  By dint of much contortion I managed to remove the motor's aluminium cover, which is all one piece on a DR3 - it is the DR3A, with the much simpler park mechanism, that has the rotating top to set the park position.  Scraping some of the grease off the gear left any numbers still impossible to see, let alone read with the motor tucked right up to the outer panels on the nearside footwell box top, but the mobile phone does have some uses.  I stuck mine up past the ventilation hose and took a blind photo of the gear, not expecting much success.  Amazingly, this yielded a photo that actually included the stamping:  120°.  So it's not the motor, then.

Re-contorting myself got the cover back on the motor and the web research began.  A quick email to Dan Case got the usual super-quick response from Montana (does that man ever sleep?), with an attached sheet of research notes (written by Dick Roush - thanks, Dick) on the topic of Cobra wiper wheelboxes.  I had bought a pair of wheelboxes from Hawk when putting the car together, as that's what I had used in my old Hawk.  I had omitted to consider that the Hawk uses the much more modern round-cased 14W wiper motor, whilst my car has the original DR3.  The gear arrangement is different in these, so Hawks have different wheelboxes to compensate.  Thus my car's wheelboxes were the Hawk-style Lucas 32-tooth type, whereas the DR3 120° gear dictates that the wheelboxes should be Lucas 72686 wheelboxes with 22 teeth.  Hence the missing 30° of wiper sweep on my car.  There's a set on the way now from Steve Hunt, so next week I'll be delving deep behind the dash again - oh joy.  

I know you will have been rivetted to this gripping piece of Cobra information - whatever next? - I hear you cry.  Well, get the spanners out - every Cobra used this same setup, so shame on you if you have anything else.  

p.s. - oh yes, the washer bottle - outlet hose had fallen off the pump inside the bottle.  A couple turns of stainless lockwire to stop it doing it again looks to have done the trick.