rear main seal

[croatankid]

I intend to take my a4ld out in a few days and thought I might as well change my rear main seal. I understand that I can hook it with a pick and just pull it out. I saw that on YouTube. Putting in a new one is not so clear. I've never seen this specific seal. Does it have a metal enclosure? If so, can't I just tap it in? On YouTube a guy used a piece of PVC pipe to drive the seal in. Can anyone here give me some insight? A YouTube video would be nice.

 

[backporch]

I recently had access to my rear main seal and didn't replace it. It wasn't leaking so I left well enough alone. Part of that is ignorance and part is fear that I may cause an issue or put in a crap seal.

I don't like those seal pullers. I worry about scoring the surface of the crankshaft that is being sealed and generating a leak.

I had replaced a front seal on another vehicle and the advice I found at the time was to attack the outside of the seal between the block and seal... provided it isn't recessed too much and I don't remember if this one was. The thinking there is that even if you gouge the block, the new seal will slide in and has a darn good chance of avoiding a leak between the seal and block. A dab of silicone also helps if there is minor destruction there. You just need to catch the metal part of the seal and pry it out. I tapped a small screwdriver into the edge of the seal and was able to work it out.

As far as driving the new seal in, this isn't one that has the seal integrated as part of a rear "cover" that can be removed. It is part of the block and driven past the edge of the crankshaft... maybe even recessed slightly into the block.

For this kind of stuff I like to do a lot of planning, so when I am under the vehicle upside down it is foolproof. I did something like this with my toyota prius transmission axle seal. It had to be about 1mm beyond the edge of the transmission. I created a copper ring from electrical cable that had about the same diameter as the seal needed to be recessed and used that to push the seal the last little bit.

So given the task you are about to go through, I would get a caliper and measure the crank shaft diameter and head to the local Home Depot and figure out if they have any PVC fitting that fits nice over the crank and extends beyond the edge of the seal to prevent you from driving the seal too deep. If the seal is recessed maybe you can come up with some way again of not letting yourself set it in too deep. Toyota had a special tool. I had to make one but it worked out great.

 

[adsm08]

I like to punch a little hole it in with a nail then run a wood screw into the hole with a drill. That alone usually pushes the seal out if you manage to hit a counter weight.

If you are careful you can tap it in with the edge of a 2x4.

 

[croatankid]

Thanks, I'm going to wait and see how it looks and also what kind of seal is in there..

 

[Elutheros]

I have the specific $150 tool for installing the 4.0 rear main seal with the micro shim if you are interested. I'm never going to use it again. I works very well for the installation.

 

[bwdedgar]

No YouTube link, but I second the PVC pipe. My dad and I just replaced this recently on my 94. We just took the new seal and bought a small piece of pipe that fit! We also used the screw trick to pull the old one out. A word of caution, I replaced mine with an aftermarket brand seal and unfortunately I believe there is still a small leak. Go with the Ford part, which has the metal enclosure.