How long does a rear main seal last?

[Toby]

Thanks for the detailed post Toby! I have a question on 2). Are there any aftermarket VW rear main seals made from Vinyl? I thought most seals are made from NBR (Nitrile Buna Rubber) and biodiesel resistant seals are made from Viton.

Can you tell what a seal is made of from color alone? I bought the Elring rear main seal/carrier and it is black. I have a red rear main seal from a seal kit from Prothe and it is red. So The Prothe seal is Viton and the Elring is Vinyl? I wonder what color is the VW OE seal? I'll take some pictures of them and post later.

I have seen vinyl rear main seals, but it's all about what came on todays boat from china. If you want to buy a box car load of chartreuse rear main seals some chinaman will sell you all you want.

Red almost always means Viton or NBR. These seals are soft and pliant like rubber they are. Vinyl is harder and not at all stretchy.

Why would anybody buy the seal and carrier? Its much easier to just replace the seal All of this worrying about getting them parallel to the block is a bunch of silliness. If it is straight in the carrier you are good to go. Just feel around with your finger. If the seal is at the same level as the edge of the bore, you are good to go.

[theman53]

I have bought the seal in the carrier as that is how the Teflon ones come. They take m7 bolts, but are supposed to last forever and do not cut into the crank. A little pricey as the last one I bought was 35.00

[92EcoDiesel Jetta]

I have bought the seal in the carrier as that is how the Teflon ones come. They take m7 bolts, but are supposed to last forever and do not cut into the crank. A little pricey as the last one I bought was 35.00

Where did you buy the Teflon one and how much? Does it have a spring under the seal lip? The Elring seal/carrier I just bought does not have a spring which is concerning. I'll post some pics shortly.

[92EcoDiesel Jetta]

This is the Elring from FCP https://www.fcpeuro.com/products/audi-volkswagen-engine-crankshaft-seal-rear-068103171f


It does not have a spring under the seal lip- wtf? The rubber also looks and feels weird. I don't have a good feeling and will not be putting it in and will return it.

[92EcoDiesel Jetta]

Further looking I find the tag on the box the Elring seal came in says:


SP LD PTFE/ACM
1 stuck 804.850
4 041248 051320



I was not able to find the above numbers in Elring's online catalog, just the following general info on their line of seals:


Per this pdf ACM is another material (polyacryl rubber)  http://www.elring.de/fileadmin/Dateiablage_DE/1Produkte/RWDR_VSD/Elring_RWDR_Bauarten.pdf


http://www.elring.de/fileadmin/Dateiablage_DE/1Produkte/RWDR_VSD/Elring_RWDR_Bauarten.pdf


http://www.elring.de/fileadmin/Dateiablage_DE/1Produkte/PDFs/Montage_RWDR.pdf


http://www.elring.de/fileadmin/Dateiablage_DE/1Produkte/PDFs/Montage_PTFE_RWDR.pdf


I emailed Elring to get product info on the seal.

[Dakotakid]

All you need is a $7.70 seal from autohausaz part number 068103051G

THIS is the seal you need....period. No pink ribbons, no French tickler, no nothing else......just THAT.

And, a little common sense while installing it.

Use a conical piece of plastic with light grease or Vaseline (to slide it into place) and then push it into place with your thumbs. Then use a small piece of flat wood to ensure placement around the perimeter.

That's it.....no waving of hands.....no endless discussions.....no holding your breath and turning blue.

[92EcoDiesel Jetta]

fatmobile, I found this youtube video by a guy who is a pro mechanic (I think). At 1:13 he taps the seal in with a hammer. Is that going to be a fail?  https://www.youtube.com/watch?v=XXyLd0V-pLI

[fatmobile]

Tapping it in or getting it started with a hammer is a good way to go.
I like the way he tapped evenly around the edge.
 With such a large seal it's hard to get it all started at once.
 I start it the same way, until the inner lip is past the edge of the crank.

I don't like that he never mentioned greasing the seal lips before install.
 
Like many who think it's silly.
 I never used to look at the seal before or after removal.
Just tapped it flush with the surface of the seal carrier.
At some point the misalignment became too obvious to ignore.
Some times it works.
 They might have changed the later seal carriers so they are more square on the outside surface.

[92EcoDiesel Jetta]

I've been busy with personal matters and will be getting back into it and finishing up the clutch job and other side jobs. After much research, I will be replacing the rear main seal with the Teflon seal/carrier afterall, even though the current one is not leaking. I will take some measurements of the old seal/carrier to see if the carrier flange is square. A visual of the old seal/carrier appears it is square, i.e. the seal is not cocked relative to the flange outer lip.

[TimpanogosSlim]

Offered as an anecdote, what my machinist friend told me.

He's worked at an automotive machine shop for 12 years, doing nothing but rebuilding engines. He does initial tear-down and cleanup, specifies parts to be ordered, and does the final assembly. Someone else bores blocks, someone else builds heads, etc.

The shop he works at warranties their engine builds against leaks. So a rear main seal leaking means that he gets to replace it for free.

He says that around 8 years ago, it seemed like brown rubber seals were coming back more often than black, graphite impregnated seals. So he started placing bets, when he heard that an engine was coming back for a new seal, that it was brown.

And he was almost always right.

Two other things.

At his shop, the old seal gets pressed out of the carrier, and the new seal is installed thermally. Which is to say, they have a hot plate that they heat the carriers on, and then when it is hot enough they drop the carrier onto a stainless steel table, drop the seal into the carrier, and simply wait for the carrier to shrink around the seal.

Aside from that, seals never go onto the engine dry. Whether you oil them or grease them? I dunno.

[92EcoDiesel Jetta]

seal is in!

Old seal/carrier off surfaces cleaned. The new Teflon seal/carrier does not need the paper gasket.


I applied a thin layer of non hardening sealant (Loctite 30515) all around the flange mating surfaces. Note how the provided cup sits. The cup bottom is wider than the lip and the bottom sits against the crankshaft, as the flange to pushed towards the crank, the seal lip is spread apart as it goes over the crank nose.


carrier bolts in torqued to 15 ft lbs

[92EcoDiesel Jetta]

After you do a rear main seal, do you test it by running the engine before putting the tranny back on or do you trust the quality of the seal (and the quality of your work) and test it by driving?

[wolf_walker]

All this seal talk and no mention of wear marks on the crank with these high mileage motors.
That has been the single biggest problem I've had with leaking seals(new ones) on old cars, of any sort, ever.
Speedysleve and readysleeve are good stuff.

(and factory Porsche RMS are black fwiw)

[Rock3tman]

I've finished rebuilding a bone-stock 1.6TD with 231K miles:  The crank main and rod journals were unmarked and measured for stock size bearings (no oversize at all!!)
but the crank rear seal surface and both of the IM shaft surfaces were prominently grooved from the stock seals so that you could easily feel them with a fingernail - - with two grooves on the crankshaft rear seal.   

I used ready sleeves for all three and hope for another 200-250K.

[92EcoDiesel Jetta]

................
Like many who think it's silly.
 I never used to look at the seal before or after removal.
Just tapped it flush with the surface of the seal carrier.
At some point the misalignment became too obvious to ignore.
Some times it works.
 They might have changed the later seal carriers so they are more square on the outside surface.

I got a micrometer and accurately measured the old flange thickness all around to be 0.626", so it is square. The old seal (marked W. Germany) sits flush with the flange. Tapping in a new seal flush to the old flange that I have will result in a seal that is square to the crank nose journal. I does not matter in my case since I replaced it with a Teflon seal/flange assembly.

It does not make sense to me why the flange would be made so it is not square. Can you think of any reason why that would be done?