rlich8

I am at the end of my timing belt job. Car runs great. All is finished except for one problem that is escaping me...

My oil pump will not stop leaking from the front shaft/seal. I have gone through 3 seals and they only seem to last a few minutes before they begin leaking. Large o ring and bolt o rings are also new. Have also been sure to install pump in proper orientation.

I triple checked belt tension and position of cams and crank before I ran the car so I highly doubt the pump is being "pulled" too hard by the timing belt.

My thought is that the shaft is somehow damaged and the pump needs to be replaced. FYI the car has normal and good oil pressure.

Any thoughts?

Ducman82

what way did you install the seal? is it pushed down far enough? seated flat?

dr bob

Steel gear with the little spacer still in there behind it as it was with the original aluminum gear? Otherwise, look for scoring on the shaft where the seal rides. Be aware also that the seal will be damaged if it's passed over a sharp corner on the shaft. I don't remember whether the 928 pump has a shoulder that the seal rides on, larger diameter than the shaft where the gear sits. If you push a lip seal over that edge, it cuts the lip on the seal and you have leakage. easy temp workaround to a seal installation sleeve is a couple wraps of Magic Tape (from the desktop dispenser...) just over the sharp edge, so the seal lip can pass over without cutting. Best to lube the seal lip with grease to give it a fighting chance on initial start-up.

With luck, GB will share his wisdom on this. I'm a hack compared with Greg.

Mrmerlin

FWIW if your installing the new steel gear then the 1mm spacer is removed from behind the gear.

Was this pump from this engine?

Is there play in the oil pump shaft to housing?

Did you dress the end of the seating surface shaft with some 600 grit paper to remove any burrs?
Has the woodruf keyway been removed while installing/ removing the shaft?

The gears should have the dots facing the block when installed.

Please post a picture of the pump installed in the block ,
and the tip of the shaft without the gear installed.

Use STP oil treatment to assemble the pump and lube the radial seal .

NOTE when fitting the radial seal it get seated flush with the housing.
gently install the shaft while adding a slight twist .

NOTE when you remove the shaft see if the small spring has come off its seat behind the seal

rlich8

Yes, I did it with a bit of grease, pushed down as far as possible, seated flat.

Steel gear, but no spacer. It didn't come off of there with one, and PET isn't showing one for the 16V engine. There really are no sharp edges or wear on the shaft, which is why this is so bizarre...

rlich8

This pump appears to be original to the car.

No play.

I took the time to carefully inspect and thoroughly clean everything with a parts washer. I then used 800 and then 600 to smoothen up the already looking-good shaft.

Woodruff key definitely removed and only installed upon reinstallation of the gear.

I installed this pump in the correct orientation.

I'll get another seal and try this all over again just to be double sure, but I think we have a bizarre problem with my pump.

Ducman82

100% sure is that seal?

Mrmerlin

to install the new seal after you have inspected the old one to determine if the spring has fallen off,
simply put the seal into the bore ,
then place the seal and pump on a flat surface ,
and press the pump housing till the seal is flush, dont go further.

rlich8

Yes.

rlich8

We'll try again next week! Thanks!!

rlich8

What about the possibility of an issue with one of the oil pressure relief valves?

I have done everything properly several times now. I've been around enough engines including rather exotic ones to have competency in doing this seal installation. I also have trouble believing that there's an issue with the pump, and I'm just trying to be thorough.

jwillman

My oil pump leaked but not from the seals. The mount bolts have a special coned washer that contains an oring under the cupped washer.

rlich8

Yes, I have those coned washers present with the blue little o-rings underneath them.

hacker-pschorr

What is the history of this engine? Was it running before you took it apart?

I know, odd question but my oil pump did the exact same thing when I installed a later pump in my 81. The drain back is different and that was blocked (by the wrong pump) so all that pressure came out the front.

rlich8

It's a healthy engine. I did a timing belt water pump job. I did not rebuild the engine and it shows all signs of being a healthy motor.