Author Topic: Rear Main Oil Seal  (Read 1663 times)

pede754

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Rear Main Oil Seal
« on: April 22, 2023, 20:16:28 »
My car is a later 250.
After reading that the lower part of the rear main was a doable fix with a good chance of a reasonable outcome I set about the change and indeed it made a massive difference on my car. There is still a weep but I didn’t expect it to be so good.
This post assumes a certain knowledge of disassembly so lots of work is not covered but is obvious when you start.
The suspension drop out is simple and quick, the steel sump pan was stuck well and in hindsight doesn’t need to be removed. The crankcase lower dropped of very easily which took me by surprise.
The crankcase lower refitted really easily with a couple of long guides screwed in one each side.
I bought an OE seal and pushed it in with a big socket which worked well, the seal was left proud and with 3 sides chamfered. The top half was left in obviously due to the pin but we attempted to punch the seal to allow the lower half to sit in. Not at all sure it is as good as it sounds but it worked!
I had already done the front crankshaft seal which was leaking pretty badly and the combined leaks always coated the entire underside, back end of the car and garage floor!
170 miles and looking like a massive improvement but I accept that it isn’t as good as doing the job properly. However an engine out, crank out job is a lot of work!!
Sadly can only post 4 photos 🤷‍♂️

Kevkeller

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Re: Rear Main Oil Seal
« Reply #1 on: April 22, 2023, 20:43:02 »
Here’s a dumb question. How’s the engine being held up?  Do you have it held up from above?

Glad it worked out. 
1970 280 SL

pede754

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Re: Rear Main Oil Seal
« Reply #2 on: April 22, 2023, 21:18:31 »
Yes it was 😀 I have an adjustable bar across the shock towers

Charles 230SL

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Re: Rear Main Oil Seal
« Reply #3 on: April 23, 2023, 12:59:24 »
Pede, great success story - glad it was a favorable outcome

roymil

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Re: Rear Main Oil Seal
« Reply #4 on: April 23, 2023, 13:35:03 »
Thats creative problem solving at its best.  thanks for sharing.   Do you have a picture, or can you further describe the adjustable bar across the shock towers?  I'd like to drop my front suspension for maintenance and I'm curious to know how strong the support needs to be and what it takes to support the engine like that.   I assume a pretty heavy steel bar is needed...how much weight is that? 
Mark Miller
1968 280SL
Rode in his pagoda's first mile.

Duncan200

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Re: Rear Main Oil Seal
« Reply #5 on: April 23, 2023, 13:54:13 »
Hi Mark,

I would hazard a guess, something like this.

I just googled Engine Brace.

We used to use them on FWD cars when doing clutches.

Cheers Doug.
1966 MB 230SL DB 717 4sp Australian Delivered Matching Numbers Car. One day it will be back on the road in all its glory.
2000 MB CLK430 Convertible
2001 Nissan 200SX Spec S
2019 Audi SQ7 Special Edition

pede754

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Re: Rear Main Oil Seal
« Reply #6 on: April 23, 2023, 16:02:55 »
My support is very similar but with just one hook, it is nowhere near as good as a twin hook would be.
I put blocks of wood onto the shock towers to mount the feet on.