Rear Main Seal Replacement

[Doakster]

Pulled the trans this weekend, and my rear main seal is slightly leaking, so while i'm in there i'm going to replace it.

I don't have my bentley manual with me at the moment to reference but it looks like there is a retainer plate that holds the seal in.

Any special tools needed or does tightening down on the plate actually press the new seal on for you?

[Rabbit on Roids]

dont even worry about the aluminum boss it mounts in. just pry the old seal out, grease the new seal, and install it. you can even get seals with the aluminum piece, all brand new and pre assembled.

[VWDoc91]

Do it with a large screwdriver. Just don't scratch the aluminium surface, though.

[Doakster]

Thanks fellas, so i take it your just gently pushing in the new seal by hand correct?

[rallydiesel]

Most new seals most come with a plastic cup-shaped thing to slide the seal over the crank end. You don't really need it though. Just lightly grease (with engine oil) the crank end and carefully slide the seal over it. Once it's on, look closely to see if the lip has bent over on itself. If it has, you can usually gently slide a thing plastic object like a plastic dinner knife under it to pop it back up. If this doesn't work, just pull it off and try again.

[ilikevwdiesel]

I make sure to buy a meistersatz replacement seal with the plastic installation aide. Remove the aluminum retainer, install the new seal and then reinstall the retainer. The plastic guide makes the installation foolproof, otherwise you could install the seal and unknowingly have the lip spring fall off inside and not know it. The result would be a leaky rear main seal.  

[Doakster]

I make sure to buy a meistersatz replacement seal with the plastic installation aide. Remove the aluminum retainer, install the new seal and then reinstall the retainer. The plastic guide makes the installation foolproof, otherwise you could install the seal and unknowingly have the lip spring fall off inside and not know it. The result would be a leaky rear main seal.  

Can you elaborate a little more on the meistersatz seal with the plastic aide? Know where to get one or have picture of the install aide?

[ilikevwdiesel]

try this link: http://www.germanautoparts.com/Volkswagen/Jetta/Engine/65/1

it's the third pic down

[Doakster]

try this link: http://www.germanautoparts.com/Volkswagen/Jetta/Engine/65/1

it's the third pic down

That explains it, I had planed on getting the seal from them anyway, thanks.

[Rabbit on Roids]

why would you need a piece of plastic to tell you that its done right? must be like a huge version of the things you use to install valve seals? i hate those things...

[fatmobile]

That guide is a big help.
 You can make your own with a plastic sour cream container.
 Trying to get the outer edge of the seal to sit in far enough so it won't flip out, while at the same time worrying about not flipping the inner seal is a pain.
 The sour cream pint lines up the inner seal lips and gets those over the end,.. and helps a little to keep one side of the seal from popping up when you tap the other side down.
 Don't tap the seal in until it's flush with the seal carrier. That's not a machined surface and is not square with the crank.
 Look at the old seal before you pull it.
The seal lip sits equal distance from the end of the crank all the way around,
 The seal doesn't sit evenly in the seal carrier.
 Fill the seal lips with grease.

[Rabbit on Roids]

maybe i just got lucky. ive never had to do a main seal on one of these things. the last engine i built, i didnt buy new seals, the guy before me put seals in it like 800 miles before i got it and they still felt nice and soft so i re-used them.

[ilikevwdiesel]

I made one once with the top cone of a two liter soda bottle.

[bajacalal]

Though I haven't done this on a VW, I have used different sized pieces of plastic pipe to aid in seal installation (I like the ABS pipe better than the PVC, I think ABS is more durable). I just went to the hardware store and bought a selection of sewer pipe couplers in different sizes. That is my seal installation kit.

If you have the right sizes, you can use a smaller diameter to center/guide the seal and a larger diameter of pipe to tap the seal in. I usually put a block of wood against the pipe to tap it in lightly with a hammer but this is tricky to do with only 2 hands.