Replace the rear seal OR not replace the rear seal, that is the question????

[bjenterprises]

Okay guys (and possible girls). I have really appreciated the help with tips on how to replace my 300sd engine. People have suggested while I have the engine out I should replace the rear and front seal. Well I had a friend come by to help me replace the seal and he said it is a rope seal, so I will have to take off the oil pan and partially remove the crank. He said it is not a simple job!!! The existing one (I didn't see any leaks) does not leak but the engine has 150k on it. Is there a secret I don't know about in replacing this seal? Should I bother?
One thing is for sure this is taking longer than I thought it would. Heck, the bolts holding on the fan were so stuck I rolled all the edges of the bolts and ended up using handy dandy vise grips. I must really like these cars.
Any help would be greatly appreciated.

[1985 300SD Sady]

The thought of getting a fresh engine in a car, then having to take it back out again due to a leaky front/rear main seal makes me cringe.

IMO, If I was doing it again, (I am still completing an engine swap) I would deffinatly take the extra time to replace all main seals, or at least the ones that you would have to take the engine back out of the car to replace.

Just my $.02

[bjenterprises]

I am leaning towards replacing all of them. I am just wondering if the rear seal is as difficult to do as my friend made it out to be.
Thanks

[1985 300SD Sady]

Well, I know that you would not only have to remove both oil pans (upper and lower) but also, you have to take the crankshaft off it think.. I think that it is in the HAYNES but, I cant seem to find mine at the moment. You would want to get an engine stand to do it on, unless you want to climb under an engine dangling and swaying from a chain hooked to a hoist that could let the engine drop on you at any point in time.

[engatwork]

The crank will have to come all the way out to replace the rear main seal. I would replace it if I were you. Use brand new razor blades to cut the new seal with.

[P.E.Haiges]

bj,

I wouldn't replace the oil seals if they show no sign of leaking. Many of these engines have gone 500,000 miles with out replaceing the oil seals. And there is always the chance you don't do a perfect job replacing the rear seal and it might leak where it didn't before.

The front seal is easily replaced with the engine in the car.

If it ain't broke, don't fix it.

P E H

Originally Posted by engatwork

The crank will have to come all the way out to replace the rear main seal.

That s@%#s, because that means the engine has to come out.
That is a big job that I'll have to do soon too.
I noticed that oil(engine) is leaking from the bell housing.

O well, it looks like I have a summer vacation project next year.
Might aswell do an auto to manny conversion while the
engine is out.

Louis.

[phantoms]

Originally Posted by mb123mercedes

That s@%#s, because that means the engine has to come out.
That is a big job that I'll have to do soon too.
I noticed that oil(engine) is leaking from the bell housing.

O well, it looks like I have a summer vacation project next year.
Might aswell do an auto to manny conversion while the
engine is out.

Louis.

Sound like a perfect time to freshen up the engine too.

[Hatterasguy]

While you have the crank out... Maybe a new set of main and rod bearings. Also a new oil pump and chain couldn't hurt. Then flip the sucker over and do the timing chain, re-seal the oil filter stand. While the engine is out you might as well replace every seal that you can think of.