Brakes and calipers on the AP-7 at Granollers

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.

1
Tightness test
Section-by-section pressure drop against factory specifications.
2
Part replacement
Chamber, valve or line fitted with approved components.
3
Adjust & grease
Pushrod stroke and slack adjuster lubrication per service schedule.
4
Test 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 · Granollers

Half-way along the corridor, this stretch merges the flows coming off the border with those climbing from Barcelona: braking, overtaking and lane changes without pause.

Granollers and Vallès Oriental access. Dense logistics zone, heavy industrial warehousing. Dangerous curve at km 84.

AP-7

13 – 14

Granollers

Cataluña

24/7

24 hours · 365 days

La JonqueraAP-7 · 2 – 4 · 0 km FigueresAP-7 · 5 – 6 · 18 km GironaAP-7 · 7 – 9 · 45 km BarcelonaAP-7 · 15 – 21 · 145 km

Questions about this stretch

Can you come into my warehouse or estate if I can exit the motorway?

Yes — that's the preferred option around Granollers: we attend inside estates and yards whenever the truck can still move a few kilometres. Leaving the motorway also saves waiting time on the shoulder.

How does Vallès traffic affect your arrival time?

Rush hours (7–9:30 and 17–20) add genuine delay. You get an honest window on the call and, if you're near an exit, we propose the exact spot to meet.

Do you cover the C-60 towards Mataró and the C-17 towards Vic?

Yes, both axes start from our exits. Tell us the road and kilometre marker in the first message so we can plan the van's route properly.

Other services at Granollers

Mobile tyre service AP-7 · Granollers Roadside mechanical breakdown AP-7 · Granollers Air suspension repair AP-7 · Granollers Reefer and cooling units AP-7 · Granollers Diagnostics and electrics AP-7 · Granollers

Brakes and calipers on the AP-7, Granollers