Sunday, October 14, 2012

Oil Leaks - Rebuilds # 2 & 3

Jacks first...
Engine has to come out...
It was a major milestone to get the engine in and running this summer, but it was hardly the end of that process.  One of the reasons for testing the engine was not just to see if nothing disastrous happened (it didn't) but also to see if any minor problems with the build cropped up (they did).
And away we go!
Back on the dolly it goes
If brevity were my goal here, I could list the things that went right, but in fact the purpose of this journal is to chronicle the actual events, and typically one step forward--getting the engine to run--is followed by two steps back, and this was no exception.
Shortly after shutting down the engine, I had a look up underneath it to see if there were any oil leaks.  Sadly, there were.  From what I could tell, it looked like I had three leaks.  One was from the front, and I couldn't be sure if it was the oil pressure relief nut or the main seal up under the flywheel.  Another leak was obviously coming from the oil screen cover on the bottom, and a third leak was abviously coming from the oil pump.

The clutch comes off first...
Then the flywheel comes off
This meant taking the engine back off the frame and putting it onto a dolly to work on.  All the steps were familiar by now, so I didn't have to spend a lot of time looking at the service manual, thankfully.  I did have to proceed slowly to see what exactly was the source of the leaks and make the necessary adjustments.

The main seal seems good...
...no leaks here
After removing the clutch and flywheel, I had a look at the main seal, and thankfully my nightmare was not realized.  The main seal was fine, and even though there was a bit of oil visible, this was after the flywheel came off.  No oil was inside the flywheel, so this meant the seal was tight.  
The next possible source was the oil pressure relief valve nut.  Sure enough, this was loose.  Not just not torqued down, but actually loose.  Ack.  Embarrassing, but actually, this was an easy fix, as simple as tightening the nut.  That should do it for the front leak.  Now to the bottom.

This cover is a problem
Actually its the studs
This wasn't hard to find.  No question about it, it was leaking from the oil cover, and it was obvious why.  The cover is held in place by six little nuts, which are supposed to torque down the cover on six little studs that stick out of the case.  These studs are notorious for getting stripped when overtightened by an inexperienced mechanic with a ratchet and no sense of how tight these little suckers are actually supposed to get.  In fact, if they are not stripped, it doesn't take much to tighten down the cover, and it doesn't take a lot more to strip the studs.  

Don't worry, Dear Reader.  I didn't strip the studs.

Off it comes...
Studs get some thread locker
I did, however, manage to loosen those studs so that they no longer tighten.  Instead, as the nut gets tightened, the studs simply continue to turn up inside the case.  I couldn't think of how to keep those studs from moving, so I tried some thread locker.  This is a sort of glue that should, in theory, keep the stud in place and allow the nut to torque down the cover.  

Oil screen back in
And the cover is back on
I waited a couple of days for the thread locker to fully dry, then I replaced the oil sump screen and put in some new paper gaskets before I tightened it down.  For a moment, at least, it seemed to work.  I managed to get the nuts on securely and they didn't seem to be slipping.  I couldn't be sure, though, because the last thing I wanted to do was to over-torque them and break the thread locker, so I just gingerly tightened them to the spec torque and crossed my fingers.

The oil pump comes out
All ready for re-assembly
Next I turned to the oil pump.  Thinking that I had incorrectly installed the cover gasket, I took off the cover and remembered that I chose not to use a gasket.  Lesson learned.  I scraped off the case sealant I used when rebuilding it the first time, sanded the inside of the cover flat again (there were some marks from where the cover touched the gears because there was no gasket to separate them), installed the gasket and put the cover back on.  After all these adjustments, I put all the ancillary pieces back on, put the engine back on the frame and fired it up.
It leaked.  Not like it did before.  Not three leaks, just one, but it was still a leak.  The good news was that I knew where it was coming from and I knew how to fix it.  

And the cover is tightened down
A gasket this time...
This time I had to pull out the oil pump itself and see what the problem was behind it.  I know I put a gasket in behind the oil pump, but it was obviously leaking, so I knew something was wrong with it.  I thought I was going to have to order a puller tool just for this job, but after seeing a picture of it online, I realized that I still had one left in my toolbox from a previous VW rebuild!  It was easy to use and in a couple of minutes I had the oil pump out and knew exactly what the problem was.  

Add muffler and some tin...
Ready for another test!
Somehow I managed to leave a small piece of the old gasket on the surface of the engine block, so the new gasket never seated properly.  This was an easy fix, once I knew this.  I scraped off the old gasket and put a new one in, slid the oil pump in, put a new gasket in between the cover and gears and bolted it all down one more time.

Since everything was hooked up pretty much, I just had to drag the battery back over, put the fuel intake hose into the gas can and started it up again.  It ran like the proverbial top, and this time, there were no leaks!