What makes brakes go soft and die?

So this weekend a couple of the karts I was in developed braking issues. Initially the travel on the cable got really long (could only get brake pressure at far end of the throw). Took that one in and then on the next kart, the brakes just sort of up and died, was only able to get some brake pressure, but not enough to be useable.

Is this likely to be overheating or something? How long are kart brakes supposed to last?

My prior experiences had brakes working properly throughout an entire day of driving. First time I have experienced this and was curious. Could it just be crappy maintenance?

Seals going bad could be one issue. Typically the brakes shouldn’t require much maintenance other than occasionally putting new pads in. I haven’t touched mine all year. I put one set of new pads in halfway through the season but otherwise haven’t bled them or anything and they feel fine.

You can accelerate the death of brakes by overheating them through riding them or damaging the rotor in some way. A warped rotor or damaged rotor surface will start eating brake pads super fast too.


I think the first thing you need to figure out is if the problem is mechanical, hydraulic, or a combination of both. Inspect the system in it’s entirety and report back what you find.

Have you bled the system since it ran last?

They are not my karts (thankfully). The rental outfit I use owns and wrenches on them. My past experiences with them did not involve any brake issues whatsoever, so I was sort of wondering if it’s possibly user error that resulted in brake failure.

So what I am hearing is that normally, kart brakes don’t just up and die, they can be expected to perform without fading over multiple sessions. Going under the assumption that I’m not riding the brake, there’s no way I could be overheating these?

In that case, there’s no way that you could be causing it that I can think of. A sliding axle can cause the rotor to hit the pad while cornering and overheat them. Of course you’ll probably notice that because it’s sapping speed on entry and exit.

If its overheating, usually you’ll end up with fade on a hard pedal initially, then a soft pedal as either some of the fluid turns to gas, then close to nothing when the seals melt :scream:

Mechanically you could have had a break rod or pedal attachment, working loose. Or if its a cable only system, a cable stretching or a slipping lock somewhere along the line.

Ok thanks. For whatever reason, we decided to run a couple of their old air cooled 2 strokes this past weekend, which probably hadn’t had a butt in the seat for quite some time. I will stick with their more modern stuff going forwards.

Yeah if they’ve been laying up, another possibility is moisture in the system, which turns to steam/gas when it heats up, leaving you with pretty duff brakes.

TJ is pretty spot on. My brake seals failed early in the year and we had our local OTK dealer replace all the seals for us. Brakes immediately came back to how they should have been, and they haven’t been an issue since.

I think the most common way that they get damaged is if the axle slips and you end up dragging the brakes for a good few laps.

I literally just had this exact same issue sideline me from this weekend’s race. Stupid brakes.


I usually do brake maintenance before the season starts. Purchased a used OTK chassis this year and couldn’t determine what type of brake fluid it had. The issue was also complicated by the fact that OTK switched at some point from DOT 5.0 to 5.1. Not wanting to gamble with brake issues, put new pistons & seals in the master and seals in the caliber. The seals were 5.1 rated and used DOT 5.1 fluid. Bled the brakes before most race weekends, but that probably wasn’t necessary as the fluid always came out clear and the pedal never faded.
Replacing pistons and seals is not difficult. Note how things came apart. The only pain is bleeding the system. Just don’t be in a hurry.

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