What year is it & the model? Some of the older ones seem to be ok & run forever. I had a pretty low mileage W reg 2000 2.5 non turbo diesel. This had the Ford Iveco engine which was pretty bullet proof but poor mpg & really slow. Other than that we had quite a few problems the worst being the clutch, the slave cyinder leaked. The slave cylinder on that van was also the thrust bearing so it meant removal of the gearbox to replace. I drove it over 900 miles back from France without a clutch but knackered the
battery in the process. It still cost over £500 to get it done
this was after shopping around & haggling for the best price. We also had problems with the driveshaft gaiter splitting in France (cost 130 euros to get it fixed) not long after we got home the driveshaft on the other side started knocking quite bady as you cornered.
I've had a few Renaults & hope this was just a rouge one that had everybody else's problems
My new van base vehicle is also a Renault Master, it has the quickshift 6 automatic gearbox & it performs really well. Had it for almost 2 years/14000 miles & touch wood no problems.
My only advice would be is if you aren't sure what the potential problems are with the van either take a mechanic with you to look at it or walk away. Unless the price is really low (even then that would make you suspicious) don't buy something that alrady has a problem that you can't work out how much it would cost to repair.
Don't agree that bleeding the clutch would help, clutch juder can be caused by a few things such as a broken spring on the clutch plate, oil leaking from the engine seal.