turboawd

the op stated in another thread that its just an oring that goes bad on the vacuum cover.

https://5series.net/forums/index.php?showtopic=91920

i havent taken apart mine yet, but it seems like an easy thing to fix.

jprovence

Guys, I am tackeling this problem right now. I removed my pump last night. The oil leak was pretty bad. I took the cover off to see about sealing it back up. I wouldn't recommend sealing with RTV. That is what I was going to do. But after studying the pump and its operation, I decided against it. There is very little clearance between the oring and the moving piece. I will post pictures of the inside. Its really simple how it works. And yes, the pump is pretty full of oil when it is in operation. Or atlease mine was. There was alot of play in the rotor, almost a 1/16" or a few mm. Basiclly the cam turns a shaft, and a plastic plate slides back in fourth on the elongaed houseing. That would allow oil to most of the other side of the rotor and seep into the vacuum line. Also, the rubber hose was cracked. I am surprised my car braked at all.
BAD pic I know, I drew it at 6 in the morning

nikko64

out of curiosity..for those of us who had it fixed at the dealer...how much did it cost you? Mine was done under CPO warranty so i cant chime in.

05545i

I changed the pump myself...its very easy and and will save you alot on labor. Dealer quoted me 528$ for the part plus 1.5 hours labor to install it. So about 700$ all together. I got the pump from Garry Romani @ BMW of Newport (sponsor here) for over 200$ less than the dealer quoted me.

FWIW, it took me about 30 minutes tops changing it, taking my time, and cleaning the surrounding area.

jprovence

Here is the inside of the pump. This pump has about 88K miles on it. Notices the amount of light showing though. The slider is plastic of some sort and the tips are also plastic. They are pretty honed down.

turboawd

Did you replace or repair your pump? Was the oring bad?

jprovence

Neither yet, I am trying to find a source for the special o-ring. I think its silicone. But the rotor is pretty worn down, so a replacement I think is in order.

Cobra 427

Mine was just replaced under CPO warranty for leaking, also... (80k miles).

turboawd

even with that little gap, when that rotor starts spinning fast, it will overcome whatever air leaks by the rotor. you have to think how much volume is around the rotor versus how much actually squeezes by.
plus, maybe the rotor expands when warmed up??
i wouldnt be too concerned about the rotor.

jprovence

The pump is pretty much full of oil, And with inerta pulling on one side of the rotor, then suddenly its pulling on the other side, I think that is what makes the noise. Instead of being smooth and touching both sides of the rotor to the wall. Too much play will cause noise. I would love to compair it too a new rotor, but I wouldn't have the nerve to open a new one up.