Hi,
I have just brought a 2001 Grand voyager 2.5 CRD and when driving it back the brake pedal goes hard randomly. It can be at any press of the pedal but then when you change down a gear and brake again the pedal will work correctly.
Its as if the vacuum for the brakes is only there at high revs??!?
Has anyone else seen this or is it a common thing with the voyager?
the Vacuum pump is expensive so don't want to buy one if its not that and I don't think it is as when the vacuum is there the brakes are good.
If its any help the brake pads are all good,I changed the rear pads as they were nearly worn out and hoped that would fix it but it didn't

Any ideas greatly appreciated

 

The vacuum is also used to control things such as EGR and turbo wastegate, so I would have expected the MIL to be lit if there was a vacuum failure. However, it would be worth tracing the pipes from the vacuum pump and checking the condition of the hoses and unions.
You can get a cheap vacuum/pressure gauge for about £15 Get some extra 1/4" windscreen pump hose so you can extend the gauge out of the bonnet and around the door into the cabin and you can monitor the vacuum level as you drive to confirm the fault.

Regards
Richard

 

Richard,
Thanks for the advice. the pipes all look good and I'm going to order a tester this weekend, but you seem to have tempted fate....
The MIL light has come on twice now but not when the brake pedal is hard. It happens when the engine is warm and the revs have been high for a while. Its like its chocked up? it then goes into limp mode, take your foot off the pedal and within 30 sec the MIL goes off and your back to normal.