Your front main seal could develop a slow leak because of age, or it could be damaged from the serpentine belt snapping and getting behind the crank pulley as in this case. On my 90k car, my main seal is leaking ever so slightly, so some of you other high mileage guys may want to consider replacing the main seal if you are already doing the belt and/or LWCP.
I did some work on this guy’s car this spring and he decided to just replace the belt and not do the tensioner. The tensioner turned out to be bad and it caused the new belt to snap, resulting in this mess. So if you don’t want to be replacing your main seal, replace your tensioner and idler pulley when you replace the belt.
Here is the part you need. Part number is 079 103 051 G. Same for all years, including the RS4 and S5. It is $45 from the dealership. We needed it in a pinch so it was a little expensive. Obviously JHM could get them for a good price, and they are a great place to get all of the other “while you’re in there” parts like the belt, tensioner, pulley, LWCP, and Snub.
http://i183.photobucket.com/albums/x59/joec1992/DSCN0094.jpg
1. The first step is to get the car into service position. I did not make that part of the DIY, because it is available else ware, but I will be making one next time I need to do something on my car. After that, you need to release the tensioner and remove the belt, or whatever is left of it. In this case, the belt had already removed itself. You will be looking at the crank pulley like this:
http://i183.photobucket.com/albums/x59/joec1992/DSCN0077.jpg
2. Next you need to remove the 10mm triple-square bolts holding on the crank pulley. The pulley will most likely not just fall off, so be prepared to keep beating it with a dead blow around the circumference to break it loose. Do not be under the car when you are doing this because that fricken’ boat anchor will seriously hurt you when it finally comes free.
3. Now you will probably be able to see the main seal, and there is a good chance you will see the damage to it. I’m sure there is a better way of removing the old seal, but I will show you what worked very well for me. Get your smallest flathead and carefully wedge it between the crank and the seal. Carefully work it off, working your way around the seal. It comes out very easily so this part is cake. Be careful not to gouge the surrounding metal surfaces.
http://i183.photobucket.com/albums/x59/joec1992/DSCN0095.jpg
4. Now that you have the seal off, get a rag and clean up the surround area, making sure that there are no small pieces of rubber where the new seal will go.
http://i183.photobucket.com/albums/x59/joec1992/DSCN0100.jpg
This is what the old looks like next to the new one. Hopefully this illustrates why the next step is a little finicky, but doable with a few minutes of patience.
http://i183.photobucket.com/albums/x59/joec1992/DSCN0101.jpg
5. The first step is to oil up the new seal and the crank so that it slides on without folding over on itself. I just used some extra oil I had laying around. Now you might see why this is a little tricky. The ID of the new seal is much smaller than the OD of the crank, and it is very hard to get it on without the rubber part in the middle folding back. Start with getting it on like this:
http://i183.photobucket.com/albums/x59/joec1992/DSCN0102.jpg
6. Now keep working it on there, being careful to not let the rubber fold back on itself. I used a thin guitar pick to work it on. The hardest part is when you get it to this point here. It’s like trying to fit a garbage bag that’s slightly too small around the rim of a big garbage can. The other side keeps popping off when you finally get the one side on. I have no technical advice here, just be patient and you will get it eventually.
http://i183.photobucket.com/albums/x59/joec1992/DSCN0105.jpg
Finally on all the way!
http://i183.photobucket.com/albums/x59/joec1992/DSCN0106.jpg
So the next step I had to improvise a little bit. There was no way to push the seal on by hand, so I headed to Lowe’s to find something to make a seal press out of. This is what I came back with: A piece of PVC, a junction box cover, and an Arnold Palmer. I am letting anyone who needs to do this borrow the tool for just the cost of shipping, but you can also make your own. Long story short, I cut the pipe, and drilled some holes in the plate to accommodate for the crank pulley bolts. Here is the contraption:
http://i183.photobucket.com/albums/x59/joec1992/DSCN0121.jpg
It’s a weird process, but it goes something like this:
7a. Use the old seal to push the new seal in as far as it will go. Use the washers and the crank pulley bolts and slowly walk the new seal in, a few turns at a time per bolt. Stop when the pulley bolts bottom out.
http://i183.photobucket.com/albums/x59/joec1992/DSCN0117.jpg
7b. Now you will use the PVC pipe to walk the seal the rest of the way in. The PVC pipe is cut thicker than the old seal, so you can push it in farther(duhhh). Same process as 7a. I forgot to take the picture of this step, so this I only have two of the bolts in place here. The seal is in all the way when it is just slightly below the level of the block. It will stop going in when it’s in all the way.
http://i183.photobucket.com/albums/x59/joec1992/DSCN0120.jpg
8. Remove the contraption and inspect the seal carefully to make sure that it is seated evenly all the way around. If one side is in more than the other, it will leak, or probably wear down the rubber very fast. Now it is just a matter of re-installing the crank pulley. Use blue loc-tite and torque all the bolts to 20 ft.lbs.
Note: The pictures show the snub mount bracket removed. This is not at all necessary but it gives you more room to work the new seal on if you are doing it from the bottom.