I was doing some maintenance on my 2003 VRS yesterday and I decided to check the DV to make sure that the diaphram was OK.  I couldn't move it with my finger so I poked a blunt ended steel bar in there - it finally moved, and I could check that there was a vacuum created behind the diaphram, so all seemed ok.

 

My question is, doe anybody know if it should it be so tight that you have to move it with some force? or should it be fairly easy to move?

 

Thanks in anticipation

There should be quite a bit of resistance when pushing the piston up.

There should be quite a bit of resistance when pushing the piston up.

That's good to hear Paul, thanks.  Seems like the car is pulling a lot better since - I think it may be because I have replaced the old clips with jubilee clips - the top pipe could be pulled clear without removing the clip before.