Anyone having issues with brakes getting spongy when hot

[3UR]

DOT 5 is silicone-based and is not compatible with DOT4brake fluid however
DOT 5.1 is compatible with DOT3and DOT4 brake fluid

 

[KnappAttack]

your brake rotor is warped. when your riding the piston gets pushed back. mine does this every now and again. you go to grab the brakes sometimes(not all the time) all they'll go almost to the handlebars. if you pump the brakes they're fine, right?
it happens with boosted sleds trying to slow them down.

X2

 

[yamamarc]

your brake rotor is warped. when your riding the piston gets pushed back. mine does this every now and again. you go to grab the brakes sometimes(not all the time) all they'll go almost to the handlebars. if you pump the brakes they're fine, right?
it happens with boosted sleds trying to slow them down.

Yes exactly!!!

 

[stevewithOCD]

DOT 5 is silicone-based and is not compatible with DOT4brake fluid however
DOT 5.1 is compatible with DOT3and DOT4 brake fluid

See that kids, you learn something every day!
I never heard of 5.1 before today.
After doing some research i came up with this.

Dry boiling point of each:

DOT3=401°F
DOT4=446°F
DOT5.1=500°F

 

[lilrez]

Great stuff. This is what i love about this site.

 

[lilrez]

Motul Brake fluid, DOT 5.1 (N-S) - 500ml https://www.amazon.ca/dp/B00CMZQMKS/ref=cm_sw_r_cp_apa_i_ZdwPCbD9PR6RY

Cheaper elsewhere im sure

 

[RV125]

DOT 5.1 at Royal Distributing $17.99 CAD

https://www.royaldistributing.com/ipone-brake-dot-5-1-800313.html?utm_source=google_shopping

 

[Turboflash]

Characteristics of common braking fluids[11][10]
Dry boiling point Wet boiling point[a] Viscosity limit Primary constituent
DOT 2 190 °C (374 °F) 140 °C (284 °F) ? castor oil/alcohol
DOT 3 205 °C (401 °F) 140 °C (284 °F) 1500 mm2/s glycol ether
DOT 4 230 °C (446 °F) 155 °C (311 °F) 1800 mm2/s glycol ether/borate ester
LHM+ 249 °C (480 °F) 249 °C (480 °F) 1200 mm2/s [12] mineral oil
DOT 5 260 °C (500 °F) 180 °C (356 °F) 900 mm2/s silicone
DOT 5.1 260 °C (500 °F) 180 °C (356 °F) 900 mm2/s glycol ether/borate ester

1. ^ "Wet" defined as 3.7% water by volume

 

[ClutchMaster]

The brakes on these machines are a good bit oversized, I highly doubt your boiling the fluid. More than likely if you ride with your finger on the lever, you are inadvertently causing the brakes to drag.
Years ago I lent a friend one of my sleds to ride, he had the habit of keeping his finger on the brake lever. He wasn’t used to the newer sleds easier pulling brake lever. That was his excuse anyway.

 

[ClutchMaster]

I ride with two fingers on the lever and have caught myself dragging the brakes several times.
Ask a friend to ride behind you and keep an eye on your brake light, you might be surprised.

 

[klr650r]

Yes exactly!!!

Ah then it’ll do it cold too then, like your first time braking after a long stretch?

 

[blueironranger]

Mine got a bit of air in the system somehow this winter, never felt excessive heat in the brake area. I ended up just bleeding it and rode the rest of the season without issue. It went from starting to engage the brake about where the brake light "clicks on" to blowing through 1/2 the stroke and almost to the bars to lock the track up, pumping them up didn't do anything. I want to upgrade to the 19'+ Winder master.