small oil leak vacuum pump bottom NUT
 

hi all i have tried to stop this leak few times now fitted a brand new NUT to the bottom fixing on my vacuum pump this nut replaced the brand new genuine volvo NUT so still it weeps i have removed the NUT clean the area dry and a smear of hylomar blue but still it weeps it looks like oil travels along the thread of the anchor but it could be getting out on the surface mate of the NUT.!! the top NUT is perfect dry . any more advice on how to fix it

The nut does not seal the oil. The nut merely holds the vacuum pump tight to the side of the cylinder head. The large o-ring in the groove of the vacuum pump mating surface seals the oil.

Suggest you fit a new o-ring seal. Clean and make sure the mating surfaces on the cylinder head and the o-ring groove on the vacuum pump are clean and free of scratches, dents, chips, or burrs that could allow seepage.

Take care when fitting the o-ring to not tear it or let it fall out of place. You can use thick grease to help keep it in place in the groove when reinstalling. And tighten the nuts evenly, bit by bit so the clamping pressure is evenly distributed.

vacuum pump tiny leak
 

hi i did fit new O Ring MY PROBLEM IS I FITTED a febi pump and its got a deeper groove than the genuine peri burg so the gasket basically does not make the seal
so i got one of ebay twice as thick but still tiny leak , live with it you might say as my oil lasts the 5000 mile service , i may invest in a genuine pump when i get fed up with wiping the bottom NUT every week,