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Tuesday, July 12, 2022

More motorbike brake stuff

 "If a person gave away your body to some passer-by, you'd be furious.  Yet you hand over your mind to anyone who comes along, so they may abuse you, leaving you disturbed and troubled - have you no shame in that?" - Epictetus

 The brake fluid jell-o pudding that I recently found in the front brake caliper of the motorbike was a bit disturbing, so I thought that it would be wise to replace the brake fluid in the rear brake and the clutch.

To that end, I bought a little hand vacuum pump for bleeding brakes properly.  (the rusty circles on the shop floor are from the snow plow feet).


When I purchased the hand pump, one of the suggested purchases was a brake fluid quality probe, for measuring water content.  Brake fluid is hygroscopic - meaning that it likes to take up and absorb water over time.  This is the reason that your brake system is not vented to atmosphere.  Instead there is a rubber bladder inside the lid of the brake fluid reservoir.  As the brake pads wear and the fluid level drops in the reservoir, this rubber boot expands into the reservoir, rather than allowing humid air into the system to degrade the fluid.

Out of curiosity, and because the brake fluid tester was inexpensive, I bought it.  Here it's turned on and showing a good battery.

Rear brake reservoir.  Brown fluid, with lots of water content - every light lit up immediately.  The bike is now 17 years old, so it's probably time ;)

Below:  Clutch reservoir, also brown

Below:  Stuff that came out of the brake and clutch calipers.

Hours later, and lots of messes later - reservoirs, brake lines, and slave cylinders purged of old fluid:



After the brakes were purged of old fluid, it was time to begin the struggle again with the field mower.  I thought that I'd fixed it before, but that was incorrect.  

The mower deck was messed up worse than I realized.  Both spindles were damaged.  One had lost a mounting foot had a bent drive pulley.  Then I found that the belt was incorrect.  The one I had last purchased was a wee bit long, and the one I attempted to install today is a couple of inches too short.  This is getting irritating.  Before long it will be dangerously dry to mow the fields.  

Below:  Underneath the mower deck.  Three of the bolts were missing from one of the spindles, which probably helps to explain some of the noise and vibration.  

Right spindle is missing a foot that holds a mounting bolt, and the pulley is bent over.  Mowing rocks is hard on a mower.

On the bright side, I had a peaceful morning cup of coffee, which beats the living daylights out of starting up and shutting down a power plant, stress-wise.  We've been cycling a lot lately, and I'm eagerly anticipating several hot months of lower-stress work.


2 comments:

Johnnywoods said...

Spud if you want to be cool , racers always put a sweatband around the master cylinder. I'm not sure of the exact reason, but they all still do it.

Mark said...

I'd never heard of this before now!

I had to search a few forums, but might have found the reason for the sweatbands. It seems that the older brake fluids, when spilt on paint, would damage it, and so the sweatband was to absorb any after filling or minor leakage. Not a big deal on the newer fluids, but not a bad idea nevertheless if you go into the reservoir very often or expect leakage.

https://www.motorcycleforum.com/threads/why-sweatbands-over-brake-fluid-reservoirs.89397/