bobinyelm

2007 ML350 186k MilesA good friend just bought a 2007 ML350 that looks showroom new with 186k on it (amazing) but it had 56 DTCs and a leaking crankshaft seal when he purchased it. The car had been sold twice by a small used car lot and returned both times, so he bought it right for less than the retail of a 1997 Honda CR-V with 200K miles sitting next to it at the lot, so he's very happy.

When he bought the vehicle to my place we went through the DTCs and most were typical BS transient ones or very old ones, so I deleted them with my scan tool (Launch X431 MiniProS), and only a SRS one returned in 200 miles of driving, so we're good there.

I am a retired tech and have an indy shop and work part-time now on most makes, but most Mercedes I work on tend to be older because clientele with newer MBs and BMWs tend to favor fancy store-front shops charging more. Because of my age (mid-70s) and my vulnerability to the Coronavirus I closed my shop for now to reduce my exposure (Here in WA State we are days away from a forced lock-down anyway, as we are in an epidemic).

So my friend decided to change the seal himself, and I offered to coach him by phone. I directed him to a harmonic balancer holding tool and ordered him a new OEM seal through my distributor but did not open the box to look at it. He removed the balancer and the old seal and buggered up the new seal installing in but talking to him, and seeing a photo he texted me it's not your usual oil seal (metal base with neoprene or nitrile with a dust lip on the outside and an inner seal with a coil spring on that one to exert sealing pressure against the balancer), but rather a cup type affair with no "lip" per se to ride on the balancer surface. I'm sure I could install it in my shop with the car on the lift from the bottom side, but he is trying to do it on ramps, or from above, so that's tougher. I described how to make a seal-installer with a long crank-bolt a big washer, and a cylinder cut from some PVC pipe, but the newer type seal seems fragile.

He texted me pictures, and says the balancer itself looks great (I know some have failed) and the sealing surface has no wear groove, possibly due to the "new design" seal that doesn't have a "V" shaped sealing lip (?)

Is there an alternative "old style" seal anyone has used, or does anyone know the seal size (OD X ID X Width) so maybe he can source a seal like he wants? The old type better lent itself to shade-tree installation using a dead blow hammer and maybe a large socket to drive it home. Now, even if I were willing to see him at my shop, short of towing it over he is immobile. Plus he's my age so venturing out in public is off his play-list for now as well since they warned 65+ age people to not leave their houses/yards.

I know this sounds like blasphemy to alter anything on a Benz (He owns four, and I have owned a dozen over the years and still have 2 myself so I "get" it) but he's willing to not be a purist if it will get him on the road again, and after looking at the old design, he lacks confidence in it anyway.

Thanks,
Bob

Maj. Dundee

Why all this writing? What is it that you want to do?

bobinyelm

Fix it.

Maj. Dundee

What do you want to repair or replace?

bobinyelm

I'm sorry, I thought it was sorta clear that the front seal was leaking, and that my fried attempted to replace the OEM type seal that was flimsy and that didn't lend itself to insertion by conventional means (tapping it in and home with a soft-faced dead blow hammer) without buggering it up (as he did). But at times maybe I bury the facts under superfluous information.

I was looking to see if anyone had found a substitute oil seal of conventional type to sit in for the fragile OEM seal, but he texted me he HAD found one suitable for inserting w/o a tool.

Tomorrow he is going to start the seal w/ a hammer, then use the factory crank bolt, a nut, and a BIG washer against the seal to press it in, so I think he should be fine.

I'll post the seal part number and a photo in case someone finds himself in the same situation and finds this thread.

Bob

Maj. Dundee

Under stand that the bolt calls for a high tightening torque.

Please follow all the instructions to a t. If you do not, your engine will be damaged.

bobinyelm

The proper harmonic balancer holding tool was purchased and used for bolt/pulley removal.
To remove the bolt, a socket with a 1/2" breaker bar and a 5ft pipe was used to loosen bolt. (I was amazed the 1/2" didn't break)
The illustration in my post was the method he used to insert the seal once it was started using the bolt and washer to suck it in.
A torque wrench was used to achieve 200ft/lb, and an angle gauge between the breaker bar and the socket was used for the final torque (Though 350ft/lb +/- 50 using
a 5ft extension pipe and a spring scale hooked to the end of the breaker bar and pulled to 70 pounds on the scale should be adequate with Blue Locktite on the threads
as was originally found on he threads was found elsewhere as an acceptical gouge.)

Thanks,
Bob

Maj. Dundee

Bob, what you have posted does not comply with the Torque value in the first PDF.

bobinyelm

"Bob, what you have posted does not comply with the Torque value in the first PDF."

"Comply?"

That text should have read 150ft/lb, not 200ft/lb (the 150ft/lb he used is close to 147ft/lb or 200mn- Actually 150 ft/lb is 202nm actually) plus 90deg w/ Blue Locktite on the threads.
The "200" came from what he told me and I should have gotten the units (nm) right by typed ft/lb from habit.

The 1/2" torque wrench I loaned him only goes to 150ft/lb, and he set it to 150.

Anyway, Not my car, not your concern. MB engineers are not God, and there is tolerance with everything and 2.2nm off is no big deal, especially given torque wrenches have tolerances
and mine has been well treated but not calibrated since new.

The leak is stopped, and he's happy.

Thanks.