2018 KTM 450SX-F Factory Edition Rear Brake Locking Up!

sgrimmxdad
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sgrimmxdad
Had a messy wet race today and both motos on the last lap the rear brake locked up! I had to pour water on the caliper to get it to release. Worked fine when cooled off again. Could burnt fluid cause this? 31hours on the bike, factory fluid. Fluid change or should I tear it apart?
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kb228
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kb228 10/27/2018 2:27pm
10/27/2018 2:27pm
Id lean towards a rebuild. Just because fluid should last like 2+ years easily. It doesnt go bad in 31 hours. Use common sense and do the fluid first anyways. Costs $2 and takes 5 mins to change it.
Paw Paw 271
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Paw Paw 271 10/27/2018 2:28pm
10/27/2018 2:28pm
Change fluid and don't over fill and see how it acts. If still a problem, then tear down the caliber and clean/rebuild.

Paw Paw
project racer 10/27/2018 2:50pm
10/27/2018 2:50pm
Pads swelling up a bit due to water / heat. Run a bit more free play at the pedal for the wet ones.
CarlinoJoeVideo
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CarlinoJoeVideo 10/27/2018 3:14pm
10/27/2018 3:14pm
Agreed, change fluid.

Make sure it’s go enough play at the pedal, I’ve made mine too tight causing it to slightly drag, it heats up then locks up.
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blaze 57
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blaze 57 10/27/2018 3:43pm
10/27/2018 3:43pm
I had one of those two adjustment nuts on the rod come loose once. Locked it up and fortunately it was at home out in the field. Check those two nuts. The simple procedure or correct way to tighten them is in the manual.
Premix
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Premix 10/27/2018 4:26pm
10/27/2018 4:26pm
Make sure you’re not running the pedal to high in relation to the pegs. Make sure your pedal is releasing as well. The KTM’s/Husky return spring is a poor design. Swap for a fastway return spring. Run good fluid. 31 hours on brake fluid is A LOT, especially in a racing environment. I swap mine every 15.
murph783
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murph783 10/27/2018 5:33pm
10/27/2018 5:33pm
Could very well be fluid. I don’t know if you’re a brake dragger, but I’ve burned fluid up in a few rides. Gotta get the stuff with a really high boiling point. Especially with the extra friction from the mud
sgrimmxdad
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sgrimmxdad 10/28/2018 12:51am
10/28/2018 12:51am
Thanks guys! I really appreciate the responses. We will change out the fluid and inspect everything next week and Ill post up results!
The fluid did look a little dark, I was planning on changing it this week as we plan to service the entire bike and install the Nekken clamps!!!
swtwtwtw
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swtwtwtw 10/28/2018 4:52am
10/28/2018 4:52am
CarlinoJoeVideo wrote:
Agreed, change fluid. Make sure it’s go enough play at the pedal, I’ve made mine too tight causing it to slightly drag, it heats up then...
Agreed, change fluid.

Make sure it’s go enough play at the pedal, I’ve made mine too tight causing it to slightly drag, it heats up then locks up.
Part 2 of above is essential. Ktm/husky have to have free play in the adjustment.

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