wdornbach

Pulled my manual trans to install a south bend stage 2 clutch. While I was in there I noticed the rear main seal (rms) and the oil pan gasket (aka "half moon" rubber gasket leaking. (yes, the RMS was definitely leaking as well as the half moon)

I spent several hours researching RMS install methods. Most folks mention the necessity to remove the upper oil pan and Y pipe etc.

I assure you It is NOT necessary to remove the Y pipe and upper oil pan to effectively and correctly change out the rear main seal and half moon rubber oil pan gasket. Once I had everything prepped, removed trans, flywheel and old seal, it was fairly easy and took me about 10 minutes to install the new rear main seal AND half moon gasket.

Procedure:

Get the fel-pro BS 40631 rear engine main seal set. I got mine at Advance Auto and it was about $30. Its good quality and. It comes with the rear main seal, paper gasket, and the rubber "half moon" oil pan gasket (the OEM/dealer part does NOT come with the half moon gasket)
Also get some good high quality RTV sealant. I used the "Dirko" german stuff. About $8 at fcp euro: https://www.fcpeuro.com/products/vw-...sket-d176404a2

Drain engine oil. Remove crossmember, drain the transmission remove axles, support engine, remove trans, remove flywheel, remove old rear main seal (gently pry it off).

Clean up everything good. remove old gasket/sealant, etc. Degrease w/ brakekleen etc. (I stuffed a rag in the little hole below the crank so no debris falls into the oil pan. Remember to take that rag out before installing the seal.)

Next, remove the 2 dowl pins. The are not in tight. They can be easily removed with a good pair of vise grips. Just grip hard, twist and pull. (Do not lose them, you will need to put them back later).

Now, put a thin bead of rtv on the block (i don't know why some guys go crazy with gobs of rtv, it's not necessary,. just use a thin bead).
Next, stick the paper gasket on the block to the thin bead of rtv
Next, now that the paper gasket is stuck on the block, put another thin bead of rtv on the paper gasket.
Next, put a generous bead of rtv on the right and left sides of the upper oil pan horizontal face that mates with the seal retainer, and put a thin bead in the corner where the upper oil pan meets the block (at the bottom of the paper gasket you just installed, like where the paper gasket meets the upper oil pan. Comon, you know what Im talking about. In that corner there.). Also put a dab of rtv on the upper oil pan where ends of the half moon will rest.
Next, look at the half moon. It has a notch, so it only fits one way in the grove on the aluminum body of the seal retainer. Put a dab of rtv on the corners of the seal retainer (think under and on top of the ends of rubber half moon). It is not necessary to put rtv under the length of the half moon, since it sits in a groove and is compressed against the upper oil pan when installed.

Next put a light film of clean motor oil on the round seal lip, the crankshaft seal journal, the rubber half moon, and the half round area of the upper oil pan. Oiling the upper oil pan and the half moon rubber is the key to that rubber half moon slipping in there while you are installing the seal.

Now go for it. It's easier than you think. Just try not to get any rtv on your hands. Remember, you put the RTV on the block and paper gasket, and there is only a little bit of RTV on the seal retainer at the ends of the rubber half-moon so it should be easy to handle without getting rtv all over the place.

The following step took me about 10 minutes. Don't feel like you need to rush it, relax. if you are gentle and careful, it should go right in.

Now gently install the seal, start on the right side with easing the seal lip over the crank journal. Make sure you don't roll the lip or pop out the spring. Use your fingers to guide the seal lip. It should slip on fairly easy since it's oiled. You will have room to work since the dowl pins are removed. Watch the rubber half moon on the lower right while you are doing this. make sure the rubber half moon stays in the groove of the aluminum retainer. Once you get the lip of the rear main seal fully on the crank, don't push the whole thing in, but push it up a bit on the left side, and gently wiggle it in while you are watching and pressing in the half moon from right to left. You can use a flat blade screwdriver (get an old screwdriver and sand it down with some 320 paper slightly so its not sharp) to gently push in the rubber half moon from right to left while you are gently pushing in on the overall aluminum seal retainer. Keep working it until that retainer is all the way on, and the half moon rubber is all the way in.

Once its all the way on, push down on the right side of the aluminum retainer, line up the bolt hole and thread the bolt in hand tight. Now tap in the dowl pin just below it.

Go to the left side, grab a pair of channel locks or vise grips. to line up the bolt hole, you are going to need to squeeze the left side down to the upper oil pan. Squeeze it down until the bolt hole lines up. You should see some rtv squeeze out. That's good. Hold it in place while you thread the bolt in hand tight. Now install the top bolt hand tight. Now insert and tap in the left dowl pin.
Next, follow a sequence to tighten and torque down the 3 bolts.

You got it.

Caveat:

Removing the cross member is easier if you first just pull the 2 bolts that go through the front and rear engine mounts (and not the lower 4 bracket to engine mount bolts). Then remove the 4 main bolts (2 front , 2 rear) and off it comes. I had the cross member off in 10 minutes.

My biggest challenge was removing the passenger side axle. Those 3 bolts that hold the center carrier bearing to the block are a pita to reach. Also, recommend removing the entire passenger side strut, makes it easier to guide the axle out while you are rotating that carrier bracket.

Drivers side axle was easy. Popped it out of the differential with a pry bar.

I could NOT remove the manual trans drain plug without first removing the crossmember. Could barely get a box end offset wrench on it, and once I did it was starting to strip. So I took off the crossmember and the shifter support bracket and used a 6 point socket to easily remove the drain bolt. What were they thinking man? Dumbass location for a drain plug. I may cut a small notch out of the cross member to allow more room to access that drain plug.

Jason Chrest

nice walk through - thank you. May be a procedure we’ll do on my son’s project of a 98. Didn’t notice any signs of leakage, but may see more once we get fixing the various issues it has

JSutter

iTrader: (46)

The drain plug is in a tight spot. I ground down a wrench just enough to fit.