"What I did Yesterday..". well bad days happen, but nothing major, just a bit more work than planned. Been there? - Happens all the time to me... Must be the Climate Change or Age or something else we have to "suffer".
So to the merry tale...
A year ago I checked the brake fluid - with my new fangled moisture tester for brake fluid, cost £3 and uses 1 battery - then you don't use it for a couple of years and the battery has leaked and destroyed the tool...
But it said the car was "2-yellows" = Change it in a year, and the Moto Guzzi brake fluid showed a RED LED illuminated - so "Wet" and needs changing. "Wet" relates to a boiling point of maybe 200C to 230 deg. C., instead of the 330C to 350C of "NEW" fluid - caused by the brake fluid dissolving moisture from the atmosphere over time (we have a lot of moisture in the British atmosphere!). That doesn't mean "You will die", but as I could one day be doing the speed limit on a motorway, during a heat wave, and need to do an emergency stop with a single brake, after the traffic has forced a couple of hard stops in close sucession, then perhaps the fluid could reach boiling point and the brakes suddenly fade, with serios consequences...
For those of you with new cars, the service interval is "CHANGE FLUID EVERY 3 YEARS", and for the rest with older transport it is "CHANGE FLUID EVERY 3 YEARS"... or suffer rust and seized pistons as a result, like me!
So the new fluid was purchased and winter set in, and a 1000 other jobs, and yesterday it was time to change the fluid.
I drained the old fluid, checked the brakes, found one piston seized (RUST FROM "WET" BRAKE FLUID!! - I have learned my lesson), and re-filled the brake lines with new fluid. But there is a quirk... The 1 hour job (bad planning!) took 6 hours. The seized piston needed the re-filled system to be used to break it free, hydraulically, and it needs a new piston and seals (the aforementioned rust). The "Easy-Bleed" kit didn't do anything, as I do not have a correct adapter, and the one I made leaked..., The system doesn't drain with vacuum pump applied to the bleed nipples - as the bleed nipple simply draws air not fluid when cracked open to bleed the system, I can't reach the bleed nipple spanner on one caliper while pumping the brake pedal with another hand, it was like playing Twister with a couple of contortionists! etc. etc.
And when full of air, the master cylinders (2) that are remote from the reservoir, take ages to pump the air out through bleed nipples and draw-in the fresh fluid.
Finally, the Service manual says... "bleed the brakes, check they work enough to use the bike carefully, then after a few rides, bleed them again - until FULL braking performance is achieved".... So after bleeding twice, and no apparent air in both circuits, I now have VERY spongey brakes that need more bleeding... to try and get the elusive air out. At one stage during the filling/bleeding I was drawing a frothy mix of air and fluid from both systems. - suggests to me that something in the design (in the master cylinder?) causes this - and the "micro-bubbles" take time to float to the top as large bubbles that can be drawn out with more bleeding? I have done this process 3 or 4 times (changing fluid) in the25 years of ownership, as far as I recall, but had forgotten it is so weird. Doesn't happen with cars that have reservoirs attached to master cylinders!
So more "bleedin' fun" today!
K2