well i still aint done mine... its still in the planning stage...
You should never rush into these things.
1. Study Cam's photo. Tell the Mrs to bring you a cup of coffee and some biscuits to aid your contemplation.
2. Amass a selection of tools that take ages to find as they're deposited in random parts of the house, garage & shed, before realising you don't need anything other than a small screwdriver and a torch. Meanwhile, forgetting the most important tool for this job, a kneeling pad.
3. Study the forecast, you need a window of about 4 hours of perfect weather to tackle this 5/10 minute job.
4. More coffee & biscuits, this will keep you sustained during the procedure.
5. Finally, you put it off for another day, you don't use the rear washer much anyway do you.