Busy week with the M5.
Monday: Sorted out the well publicised dead pixel issue with the LCD on the instrument cluster - requires stripping the cluster down, drilling some holes to get at the screws holding the LCD in place (considered easier and less likely to go wrong than removing the needles) and reassembling 3 times before I got all but one line of pixels back - which I considered a success.
Tuesday: I converted to a Spal 15" electric fan a year ago, fearful of the exploding fan clutch. The shroud insert wasn't the best (quite a few air gaps) and the fan controller was a simply on/off affair when the radiator reached a certain temperature. As those who attended the last South East lunch can attest - it's really loud. So for the last few weeks I've been working with an Arduino and a MOSFET building a temperature controlled fan controller (using a y=mx+c straight line to define the speed for temperature). I've also built in an override switch (the two relays) which bypasses the controller to run the fan at 100%. The controller works by using the Arduino's PWM output to control a MOSFET opening/closing. This is done at 255 hz; to get 50%, or 6V, the MOSFET is alternately opened and closed for 1/255 of a second. Now I Just need to run a cable into the cabin for the latching button switch.
I got a disc laser cut from 4mm plastic and covered it in reflective foil for peace of mind which made a very good fan mount and shroud extension.
Initial tests have gone well - the fan comes to life at around 30% but will keep spinning until 19% (when I programmed it to switch off entirely) if it's already running and the speed decreases. More to the point, it's so much quieter than before.
Wednesday: With the MOT coming up, I was aware I didn't do the best job installing the (slightly crap) Meyle ARB drop links - the rears were almost impossible to install with normal spanners (need an ultra narrow one) without pulling the dustboot off. A similar issue at the front means all four would be better replaced now than at MOT when they'd inevitably either be an advisory or failure. Got some adjustable ones for the front (the car's slightly lowered so I took a couple of mm off the length) and some TRW ones for the back, which were much better.
In addition, I thought it wouldn't be a bad time to replace the fuel filter - a 'for life' part according to BMW (the one on the car corroborates that approach from dealers - April '00 production), but owners have found the condition to be poor from ~50-70k miles (mine's done 95k). Mine was actually really clean, but having bought the new filter installed it anyway. Gave me a chance to have a look at the sills which are really solid which is good.
Bled the brakes for the umpteenth time, though omitted the pressure bleeder this time in favour of using a trolley jack handle and the electric seat to push the brake pedal to the floor. Got some air out and the pedal feel has improved so fingers crossed.
Wanted to replace the transmission fluid (another 'for life' part) but I couldn't get the fill port undone (thankfully tried to undo it before the drain port!) with the limited space under the car, even with a breaker bar - just couldn't get any weight into it. Another time perhaps.
