BRAKE VACUUM PUMP

[dexy350]

HI
my 2,2 HDI C5 02 brake pedal gone hard, sometimes its ok sometimes its hard .now i suspect its the vacuum pump starting to give up .iam just wondering how to test to make sure this is at fault ,i have asked a few people to see if they have a vacuum tester but not much luck.
i have taken the pipe out of the servo then started the engine and put my finger over the end the suction will keep my finger on the end but i can easy remove my finger so should it be more powerful or is it correct ...
any ideas
cheers
dexy

[cachaciero]

If the vac pump was giving up I would expect you to get the dreaded "anti pollution" message and LIMP mode as the Turbo is vac controlled and no vacuum quickly equates to an overboost condition.

EDIT

You don't really need a vacuum tester as such just something to measure vacuum and a few lengths of appropriate size rubber pipe and a selection of small plastic joiners and tee pieces as sold by B&Q for plant irrigation / aquariums etc. The gauge could be any vacuum measuring device I have used at various times an old aircraft altimeter, and a refrigeration charging set. I suspect that it wouldn't be too much of a problem to modify a barometer but at the end of the day it is easier to purchase a proper vac gauge A worthwhile investment if working on modern diesel cars where vacuum is widely used for a variety of control functions.

cachaciero