Getting my newly acquired 350SDL back on the road - PeachParts Mercedes-Benz Forum

ROLLGUY · #1 11-14-2014, 11:10 PM

This thread started it all:
http://www.peachparts.com/shopforum/diesel-discussion/362185-what-involved-putting-617-91-350sdl.html

Today I picked up a 1991 350SDL that I purchased yesterday for $2,400.
The guy I bought it from bought it on ebay with only 58K miles on it for $19,900 in 2007:

I got all the service records since new:

The owners manual and stuff:

I need to wade through all the info, but I am sure I will find that this was a very well maintained car.
I will get some photos of the car in it's present condition (dirty), and then some after.
The first order of business is to patch the hole in the oil pan to find out if there is any internal damage (please read the thread linked above). This repair will not be permanent, but will be just for testing. I will try epoxy or silicone and a piece of sheet metal and rivets. I will post photos and the results here, stay tuned.....Rich

mach4 · #2 11-14-2014, 11:51 PM

You might try some of the "aluminum welding rod". It's not hot enough to warp the pan like actual welding. The stuff is pretty tough and relatively easy to work with. Small parts can be done with a simple propane torch. You might be able to get by with two torches working in concert.

ROLLGUY · #3 11-15-2014, 12:00 AM

Quote:

Originally Posted by mach4

You might try some of the "aluminum welding rod". It's not hot enough to warp the pan like actual welding. The stuff is pretty tough and relatively easy to work with. Small parts can be done with a simple propane torch. You might be able to get by with two torches working in concert.

I have a friend that has a TIG welder and he is very proficient at it. The main problem is getting it clean enough even to patch it, let alone to weld it. I think there is an inspection plate that I can remove, and I might be able to get it clean enough so no oil drips on the surfaces to be caulked/welded. I imagine that if it can be welded successfully, there would be no reason to replace the pan. If I use silicone or epoxy, I doubt I would be able to get it clean enough to weld if the silicone/epoxy patch did not work. Maybe I will try the welding first, and then seal any leaks with epoxy or silicone. Either way I still may have to replace the pan, but it is a small price to pay if in fact the innards are still good.

mach4 · #4 11-15-2014, 12:30 AM

My friend in Scotland that put the 606 in a 107 tried unsuccessfully to modify the oil pan to get needed clearance to the subframe. Even with a professional welder and the pan bolted tight to a spare block the warpage was excessive. He ended up building a pan from scratch out of steel. That's why I suggested the aluminum welding rod. It's definitely strong enough and works at a low enough temperature that warpage shouldn't be a problem.

Maybe best to just get a new pan and do it right the first time...

jay_bob · #5 11-15-2014, 06:26 AM

In his other thread he says he is just trying to temp seal the pan to see if the car is viable before investing in a proper replacement pan.

Another grand dame of the autobahn saved!

My 87 has a crack in the pan from its accident in a former life. Right where the pan hit the cross member. It has been sealed up with jb weld and has held for the last 3 years.

krwsenior · #6 11-15-2014, 06:10 PM

You're really gonna like driving this car. Mine has a lot of miles, but still drives great. Can't wait to hear about how it runs when the pan is patched.

BillGrissom · #7 11-15-2014, 08:42 PM

Watch the youtube videos using Harbor Freight aluminum rods w/ a propane torch. They melt ~750 F, whereas pure aluminum is ~1000 F, so more like brazing/soldering and less risk of warpage. I bought some to try when need arises (~$8/pk).

You are correct that welding cast aluminum is more difficult, due to porosity and impurities. I had a crack in my fairly-rare 1964 Valiant manual steering gear-box that a friend repaired with a TIG welder. He had to stop many times to chip out impurities, but the result looks strong.

benzguy300 · #8 11-15-2014, 10:29 PM

I have a good oil pan from a W126 with a 603 engine let me know if you are interested

compu_85 · #9 11-15-2014, 10:43 PM

The 3.5 and 3.0 oil pans are not the same.

-J

ROLLGUY · #10 11-16-2014, 12:04 AM

Quote:

Originally Posted by compu_85

The 3.5 and 3.0 oil pans are not the same.

-J

That is nice to know, thanks.

benzguy300 · #11 11-16-2014, 12:07 AM

My oil pan is from a 3.5

capflya · #12 11-16-2014, 12:19 AM

They are not the same but both will work on either motor. We put a w124 603 oil pan on my friends 350SD. Same bolt pattern but different oil capacity. W124 pan holds more oil because of the side-pan piece that bolts onto the main pan. Original 350sd oil pan has no side inspection hole on pass side. If it has that then the pan has already been replaced.

ROLLGUY · #13 11-16-2014, 12:31 AM

Quote:

Originally Posted by capflya

They are not the same but both will work on either motor. We put a w124 603 oil pan on my friends 350SD. Same bolt pattern but different oil capacity. W124 pan holds more oil because of the side-pan piece that bolts onto the main pan. Original 350sd oil pan has no side inspection hole on pass side. If it has that then the pan has already been replaced.

Oh drat, I thought the inspection hole on the side would ease the patching process. I guess there is not going to be an easy way to do this.

Lucas · #14 11-16-2014, 12:31 AM

Make sure you unhook any sensitive electronics if you tig it, and ground as close as possible to the work. A skilled guy on the tig should be able to do it. I would use a piece for the patch as thick as possible to focus the heat into it as opposed to the pan.

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ROLLGUY · #15 11-17-2014, 09:21 PM

I got some time to get the car in the barn to start working on it. I had no help, but was able to push the car in with Dave's tractor without any damage (sorry for crummy dumb phone camera photos):

Once I got the car up on the lift, I cleaned the oil pan:

The plan is to rough up the area around the holes and cracks, and then apply epoxy. I patched a hole in a small go cart engine years ago with epoxy and steel wool. It worked great, and I am going to try it again here. Photos to come when I do the job.....Rich