Hello i have a 2008 trafic van and when driving back from france it suffered power loss and no brakes, i took it into renault and was told it was the turbo but when i picked it up was told it wasnt turbo it was vacuum pump i drove it 15 miles an it went again with top speed of 20 mph and no brakes so back it went, 7 days later i was told it was ready and they had changed the vacuum pump again this time it did about 50 miles and it went again so had to be recovered, then renault said they would change the servo, this has gone on for 5 weeks now and have now been told that they wont fix it now as i had the servicing done by a non vat registered mechanic so warranty is void even though its non serviceable parts! does anyone no what could be wrong with the van?