Hey guys and welcome back to the SimpleCarGuy Channel. In this video I will be installing the rear crankshaft seal as part of the BMW N55 engine rebuild project I have been working on. Over the past few weeks, I have bought or borrowed a lot of specialty tools, but this time I decided to install the rear seal without the use of any specially tools so if that’s something that interests you, keep on watching!
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If you are aren’t following this rebuild project, this engine spun a rod bearing and needed a new crankshaft. I have so far replaced the crankshaft, sealed the bedplate, replaced the main bearings, rod bearings, installed a new head gasket and valve and oil pan gaskets. If you’d like to see any of those videos, check out the playlist in the description. Anyway, back to the subject of this video.
As with previous jobs I have done on this engine, the task itself isn’t that hard. The hard part is getting to the part or the rear crankshaft seal in this case. If your engine isn’t out, the recommended path of getting to it is to remove the transmission from the vehicles by removing the stiffening plate and the exhaust system past the catalytic converter and disconnecting the main drive shaft at the transmission side. The transmission can then be disconnected from the engine and dropped down. After all that work the flywheel can be removed and you will finally have access to the seal. Obviously, this is a huge job just to get to this part, but if your engine or transmission is already out and you have a leaking seal, it’s definitely a good time to change it.
I had it a little easier since my engine is on the stand, but the process is the same from this point on. First things first, we have to remove the crankshaft sensor out of the way and then remove the magnet wheel cover. To remove the old seal, you will need a small drill bit that isn’t bigger than 2.5 mm and drill a small hole without touching any metal surfaces. Then the seal can be removed with a help of a sliding hammer. I have done it without the tool before by just using a regular screw and then a regular hammer against a plank of wood that’s against the block to leverage it out of place. Whichever way you go about it, make sure there is no residue or little plastic pieces from drilling. For anything tougher, you can use a fine scotch brite pad and brake cleaner to get it perfectly smooth.
Now that we have everything ready for the new seal, you are supposed to use a special seal tool, but I decided not to buy one and used my own method so that I don’t have to spend the $300 for the install tool.
Obviously, you cannot just hammer the seal in as it would get damaged and wouldn’t create a good seal, defeating the purpose of the replacing it. So, what could you use to drive it in that’s the same size as the new seal? Well, the OLD SEAL. I flipped the seal over and lightly tapped on it until the new one started to get seated on the crankshaft. Now, this isn’t the quick method as it probably took at least 15 minutes of light and not so light hammering to get it seated. I had to stop a few times until I reached the correct stopping point. It should be just past the change in high on the block. Once the entire circumference of the seal is equally seated and will not move any further, you are done! The flywheel can now be reinstalled with new bolts and transmission put back in.
I hope this video helped you get your own rear crankshaft seal installed without having to buy any special tools and if it did, let me know in the comments down below. Check out the rest of the channel for many more BMW specific videos and I hope to see you in the next one.