Pulsing brake pedal

My problem is with a 2007 Vauxhall Combo 1.3 diesel, an ex-bt van. It has a service history and is a good van, but I have a problem with the brake pedal: when pressing the pedal, I can feel it pulsing under my foot.

My first thought was that it was a warped brake disc, so I replaced both of them along with the pads. The surfaces were all clean when fitted, the calipers were good and the sliding pins were free. It seemed to cure that pulsing problem, but now when I press the pedal it feels like it’s grinding. It seems to be coming from the driver’s side – there is a loud rotating noise that can be ‘felt’ through the pedal. You can also hear the noise bouncing off walls as you drive past.

When I had the wheels off, I couldn’t detect any noise from the bearing, which was my next thought. Or perhaps the CV joint is at fault. I don’t have a manual for the vehicle, so your thoughts would be greatly appreciated. Ray Dullick

As you have checked and eliminated the wheel bearings, my first thought is that it could be a slightly out-of-shape backplate that may be touching the discs. It is easy to disturb the backplate when changing the discs and a slight inadvertent push on one side will bring it close to the disc on the opposite side. I have done this myself in the past.

Depending on the seriousness of the grinding noise, it could also be due to a hard pad. It may be worth swapping the pads to the other side to check if the noise also transfers across the vehicle. Another possibility is a misplaced or slipped anti-squeal shim or retaining clip.

A downloadable manual for the Combo is available from the website

emanualonline.com at a cost of £9.99.