Hi all,
I've had my 2018 Roxor for about 1 year and it has ~1,000 miles / 125 hours. I have a consistent problem that occurs when I climb an incline and it's immediately after on the next stop my brake pedal nearly goes to the floor as if there's air in the system. It took me some time to notice as I didn't drive it in the winter. The master cylinder reservoir is topped up and the brakes work perfectly in normal driving. I have searched and haven't seen anyone encounter similar issues. Any ideas are welcome.
Thank you in advance.
Have you figured out what's wrong yet?
How steep are the hills you're climbing when this happens?
And it ONLY happens after negotiating a hill, correct?
What I'm thinking is, if the master cylinder is sitting at an angle already when the vehicle is on the level, and the hill you climb exaggerates that angle, you could be having a small amount of brake fluid leaking past your pistons and back into the MC reservoir, and now when you apply your brakes, the fluid in your primary or secondary circuit under the MC reservoir may not be there, and your pedal will go down a lot further than normal.
All MC's have a 60/40 braking ratio. You have 60% on your front wheels and 40% on your rear wheels.
Your front brakes are being applied before your rear brakes so you can maintain steering.
Once you step on your brakes, the primary piston creates hydraulic pressure to apply your front brakes, AND also create hydraulic pressure to be applied against your secondary piston for your rear brakes. Once your rear brakes start to be applied, the pedal gets hard. Thus you have your 60/40 braking ratio in a working system.
Okay, if the front or primary brake hydraulic system fails to build up pressure, you have a steel rod that will EVENTUALLY make connect with the secondary piston and now the mechanical connection starts to push and create hydraulic pressure for your rear brakes.....and the pedal has to go a loooong way before for this to happen.
If your front brakes are working and building up hydraulic pressure, but your rear or secondary circuit has failed, again the pedal will go all the way down until it hits its mechanical stop, and it can build up full hydraulic pressure for your front brakes to be completely applied, but again the pedal has to go a loooong way before this happens.
Now when you release the brake pedal, it comes back to its resting position, BUT it also sucks brake fluid back into those primary and secondary circuits and refills them from the reservoir, and everything is good to go again, and you have normal braking....until the next steep hill.
In any case this is not normal at all, and it "COULD" indicate your MC "COULD" be having leaking issues, and "COULD" fail if the brakes are slammed in an emergency stop.
Next time you go up a steep hill, when you get to the top, apply your brakes rather HARD, not slam them but as you would if you had to make a very quick stop, and see if the pedal goes to the floor again, BUT also see if your front end dips. If it does, your front brake circuit is working, but if it does NOT dip, and you go to the floor and still slow down, your rear brakes are working. All you're doing is trying to figure out which braking circuit could have a possible bleed back issue and do further inspecting and troubleshooting. I would also turn around and go down the same hill and see if it happens again.
It's one thing if you can't start and you can't go, but it's another thing when you can't stop or you can't steer. Both systems have mechanic backups in case of hydraulic failures, and brakes have three really since it has TWO separate hydraulic braking circuits, and a hand brake or emergency brake, but still, it's scary and the ole pucker factor is running a 110% and you couldn't pound a pin up your ass with a jackhammer when it happens.
I would also check my hand brake and make sure it's in working order just in case. It's good to exercise that system every time you drive to keep that cable from rusting up. Just get in the habit of always setting the hand brake when you park, and you'll be fine, and it will be ready if you need it.
