This 2017 Ford Transit Custom was recovered in with the brake pedal having gone rock hard whilst driving — effectively no power assistance to the brakes. This is a known issue on Transit Customs and is caused by failure of the vacuum pump on the engine.
The vacuum pump provides the brake servo with the suction needed to assist your foot when pressing the pedal. When it fails you can still physically stop the van but it requires enormous pedal effort — very dangerous at speed. The root cause on this one was wet belt fibres breaking down and blocking the internal pump components until they snapped.
Tools & Parts Needed
How to Test for Vacuum Pump Failure
Before stripping anything: locate the servo pipe that connects to the brake servo in the engine bay. Pull the pipe off the servo end. Start the engine. Place your finger over the end of the pipe — a working vacuum pump will suck strongly against your finger. On this van there was zero suction — confirming pump failure.
Step-by-Step Guide
Remove the Airbox & Pipework
Undo the Jubilee clip at the top of the airbox. Unplug the airflow sensor wire and remove all the plastic clips around the top cover. Pinch and pull off the small breather pipe from the side. Lift the top cover clear and remove the air filter. Undo the single 8mm bolt holding the DPF pressure sensor on the side of the airbox and set it aside. Pull the airbox towards you — it locates onto a bar at the rear — and lift it clear.
Remove the Bracket in Front of the Vacuum Pump
With the airbox out there is much better access down the right side of the engine. Disconnect the two pipes from the bracket area and set them aside. Undo the two 10mm bolts holding the main bracket on. Then undo the two 8mm bolts holding the small stepper motor assembly on top. Use a trim tool to help free the bracket. Unplug its two wiring connectors and move the whole bracket clear. The vacuum pump is now visible below, secured with three 8mm bolts and two pipes.
Disconnect the Vacuum Pump Pipes
The top pipe has a red collar — push it down and wiggle the pipe up to release it. The second pipe uses a squeeze-together type clip — pinch it and pull the pipe free. Now nothing is connected to the pump.
Undo the Three 8mm Bolts & Remove the Pump
Use a quarter-drive 8mm socket on an extension to undo all three securing bolts. Some will be out of sight — feel around with your hand. Pull the foam cover back slightly at the top if needed to access the third bolt. Once all three are out, pull the pump out from the bottom first, then slide it out towards you and up over the pipes. On the bench you can clearly see the wet belt debris that destroyed the internal rotor.
Fit the New Vacuum Pump & Gasket
Put your finger into the cam drive hole to feel the orientation of the cam lobe so you know how to align the pump drive. Feed the new pump in over the pipes the same way it came out. Wiggle it until the drive locates correctly and the pump sits flush against the head. Once flush, start all three 8mm bolts by hand, then tighten evenly so the gasket is clamped down uniformly. Refit the pipes.
Rebuild & Test Vacuum
Refit the bracket and all pipes in reverse order. Refit the airbox, airflow sensor, DPF pressure sensor, air filter and top cover. Start the engine and go back to the brake servo pipe. Hold your finger over the open end — you should immediately feel strong suction. Push the pipe back onto the servo and test the brake pedal. It should feel light and well-assisted with normal pedal travel. Take a test drive to confirm.
🛒 Parts & Tools for This Job
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