Brakes and calipers
A seized trailer caliper is the single most common fault that strands a truck in a service area. We free the caliper, replace discs and pads, repair air lines and fittings and change Knorr-Bremse and Wabco relay and modulator valves. Before we release you we check pressures on both circuits.
A truck brake system is pneumatic: a compressor feeds the tanks and every pedal press is really a pressure command. So roadside failures are usually about air — leaks, saturated dryers, sooty valves — rather than friction material, which is why a good diagnosis starts by listening to the circuits with the engine off.
On the move the golden rule is don't push it: long pedal travel, grabbing or a dropping pressure gauge mean stop somewhere safe and call. An axle dragging on a seized brake chamber destroys drum, linings and tyre within a few kilometres.
What never to do
- Do not force it along with a wheel locked
- Do not cool a red-hot disc with water
- Do not fiddle with trailer valves you do not know
- Pressure dropping at rest. Parked with the engine off, the needle sinks: there is an active leak.
How it works
Tank fill and pressure-drop are checked section by section against the manufacturer's figures. Once the guilty branch is isolated (chamber, valve or line), the part is replaced with quality spares, then we prove tightness again and finish with a controlled road test confirming the brakes release fully.
- 1Tightness test
Section-by-section pressure drop against factory specifications.
- 2Part replacement
Chamber, valve or line fitted with approved components.
- 3Adjust & grease
Pushrod stroke and slack adjuster lubrication per service schedule.
- 4Test run
Verification of full release and per-wheel temperatures.
Job
Brake chamber. Part plus fitting; far less than new drum, linings and tyre.
Drain the tanks of water weekly in winter, fortnightly in summer: water in the circuit is the silent cause behind seized valves and choked dryers.
AP-7 · Barcelona
The final run into the metropolitan area: traffic turns urban, stops come more often, and any breakdown here hits deliveries with fixed time slots.
Port, Zona Franca, Mercabarna, C-31/C-32/B-20 access. Extreme urban-heavy traffic mix. Fixed radars km 150-155.