Love the new rubber feel. Wish it was as affordable as the new brake fluid feel!
What's your most neglected maintenance item on your motorcycle?
- Thread starter Lightcycle
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Love the new rubber feel. Wish it was as affordable as the new brake fluid feel!
Mad Mike
Well-known member
No hand magic here, just a few decades of driving experience in cars, trucks and other. I know what to expect from my brakes and recognize when they are letting me down.
In most cases of brake failure, fluid is not the culprit - so having a little hand magic is pretty important.
For fun, I’m going to do a test on braking in the next revival. I have 2 identical twins in my garage - both 1982 xv920r’s with approx 45k on their clocks. One is plated and been completely revived ( calliper overhaul, fluid change) - the other hasn’t seen the road since 1990. I’ll compare what the braking distance is for both - might enlighten me - we’ll see.
Tires will probably be determining factor in that test. Probably a better test to use the same bike and tires before and after a brake service.
Mad Mike
Well-known member
Maybe do both. The tires are dot dated 1988 on the unrevised twin.
Yeah, like @GreyGhost pointed out, too many variables, that's not really a test.
Just get one of these brake fluid testers: https://www.amazon.ca/Taxutor-Hydraulic-Moisture-Indicators-Diagnostic/dp/B0834PVSBT - It's $10. Or bring them both to my house, I'll test them for you and we'll post the pics of our findings in the thread for science and likes lol
I always forget to change the coolant on my Katana. It's a good thing it's air cooled.
Priller
Well-known member
Cool tool. Had no idea they existed. Though based on the reviews, it seems the extra $15 for this one is well worth it. Mine arrives tomorrow.
https://www.amazon.ca/TESMEN-Corros...8cc-869c-9ce8d0b5d6aa&pd_rd_i=B0DNT3CXMR&th=1
Also does DOT 5.1 for track bikes...
I like tools but $25 buys a lot of brake fluid and ime, the worst fluid is in the calipers where you can't easily test it. Flushing purges the gross fluid quickly. For bikes that spend most of their time sitting (eg for people with many bikes), the reservoir may have the worst fluid and a quick test lets you know whether to wrench or ride.
EDIT:
There is a newer version of the tester you linked for another couple dollars.
You're not going to notice brake fluid contamination in a one-off stopping distance test. You could flush the entire system out with water and use that in place of brake fluid for a one-off test, and it will work fine. Boiling point issues will only turn up if you do something that leads to substantial heat build-up ... like using the brakes hard repeatedly in racetrack duty, or using the brakes going down the side of a mountain while heavily loaded, etc. (On a related note, Yamaha Racing posted a picture on social media of the brake cooling ducts that they're using in WorldSBK this weekend. Tight, twisty track, so lots of repeated heavy brake usage, and not all that many long straightaways for them to cool off.)
Where contaminated brake fluid comes back to bite you is when contamination and corrosion lead to seizing caliper pistons and master cylinder pistons, and the lever starts coming back to the bar (or pedal starts going close to the floor) before it starts doing anything, and then repair requires replacing seals, caliper pistons, master cylinders, or more expensively, ABS pumps.
The easy thing to do, is when replacing brake pads, clean around the caliper pistons and push them all the way back in (you have to do this anyhow in order to make room for new pads), and then open the reservoir cap and suck all the fluid out and replace it with new fluid before applying the lever to get the pads back into contact with the rotors. This won't replace all of the fluid, but it'll get most of it, good enough for me.
Where contaminated brake fluid comes back to bite you is when contamination and corrosion lead to seizing caliper pistons and master cylinder pistons, and the lever starts coming back to the bar (or pedal starts going close to the floor) before it starts doing anything, and then repair requires replacing seals, caliper pistons, master cylinders, or more expensively, ABS pumps.
The easy thing to do, is when replacing brake pads, clean around the caliper pistons and push them all the way back in (you have to do this anyhow in order to make room for new pads), and then open the reservoir cap and suck all the fluid out and replace it with new fluid before applying the lever to get the pads back into contact with the rotors. This won't replace all of the fluid, but it'll get most of it, good enough for me.
And if you have added fluid with the worn pads, you should be sucking some out to avoid the reservoir puking. This may keep the bad fluid in the calipers though as they don't stroke down to zero volume (and the hose holds some crap fluid too).
On a past car, I would alternate between blue brake fluid and yellow brake fluid. That made it really easy to see when flush was completed. With one colour of fluid, it's hard to tell when the new stuff arrives as it is no different visually. US laws banned the blue fluid as brake fluid must be clear or yellow. So dumb. Take that environment as now I need a lot more fluid to ensure a complete flush.
Priller
Well-known member
DOT 5.1 in the track bike needs changed a lot more often. Spending $25 to save unnecessary changes is a bargain for me, even if it's to get a sense of how often changes are actually required. I don't want to be figuring that out when the lever comes to the bar at the end of the back straight...
Wait until you've had one of these for a several years. That's when the real fun starts. You start to notice certain bikes in your garage tend to take in moisture more frequently than others, despite the lot of them not getting much miles.
Now someone tell me again we're dealing with a 100% sealed system
It can't be sealed. That would put the reservoir under vacuum. They could make them lightly pressurized with nitrogen to allow reservoir level to drop without introducing moisture but I don't know of any vehicle that goes to that effort. Changing fluid is cheaper than a pressurized reservoir and annoying service procedure.Now someone tell me again we're dealing with a 100% sealed system
Does anyone here own and regularly use a brake fluid moisture tester?
Mad Mike
Well-known member
I have one of those testes somewhere. I’ll find it any try that first.
Mad Mike
Well-known member
Most are is under vacuum. The reservoirs are gasketed with a collapsible diaphragm that keeps the open atmosphere above the brake fluid.
As the pads wear and, the pistons need to go further which takes fluid from the res. The vacuum created as fluid is displaced will pull the collapsible diaphragm down, equalization air is kept on the top side, it does not mix with the brake fluid.
I sure hope you do, good luck.
Reminds me, I have to check my ball bearings and tighten some nuts.
Are we still talking about motorcycles here...?
Are we still talking about motorcycles here...?
