Hydraulics

The kart keeps its original hydraulic brakes. They are what actually stops the wheels — the pneumatic system is the actuator that squeezes them, both for normal autonomous braking (ASB) and for the emergency circuit (EBS). This page covers the fluid side: hoses, bleeding, and the pressure sensor that tells the kart how hard it is braking.

Brake lines

Flexible brake hoses with M10x1.0 female inverted flare connectors.

Bleeding / purging

The lines have to be purged of air after any work that opens the circuit; trapped air makes the pedal spongy and the pressure reading meaningless. Reference video for the procedure: youtu.be/dXhEvykyabk.

Brake pressure sensor — bought, not fitted

This sensor is on hand and unused

~/dv/kart/pneumatics/README.md records the Sensata unit as "not used in this system", and the 2026-04 Festo price sheet lists it as "Not Festo; on hand, currently unused". Nothing on the kart currently measures hydraulic brake-line pressure. Treat everything below as the plan for when it goes in, not as installed hardware.

A Sensata PTE7100, recorded in the dv notes as PTE/700-33 (datasheet). Photos of the actual unit are in ~/dv/kart/pneumatics/pictures/ (6010450369185516303, 6010450369185516304).

Range	0–200 bar
Output	1–5 V, supply 8–32 Vdc
Pressure port	7/16-20 UNF-2A (male)
Seal	HNBR o-ring
Electrical connector	Packard Metri-Pack 150
Supplied with	Neither a mating connector nor a snubber — order both separately

Adapter to the brake line: a male M10x1.0 inverted flare to female 7/16-20 UNF adapter, since the sensor's port thread does not match the hoses.

When it is fitted, its signal goes to one of the Kart Medulla's two hydraulic-pressure ADC inputs — see Kart Medulla. Its 1–5 V swing is divided down on the board before reaching the ESP32's 3.3 V ADC.

Not to be confused with the kart's pneumatic pressure sensors, which are fitted and reading: those are Festo SDE5-D10 units on the EBS air circuit, covered on the Pneumatic Braking page.

Possible alternative

Bosch Motorsport PSS-260 (PN 0261545188) — 0.5–4.5 V, 0–260 bar. Not bought; kept as a fallback if the Sensata becomes hard to source.