Differential Fluid Replacement......where do you fill and drain....? - PeachParts Mercedes-Benz Forum

pawoSD · #1 04-21-2005, 09:46 PM

Here is a picture of the differential on my dad's 1983SD, I am confused as to which plugs must be removed to fill/drain the fluid....I was thinking that "B" is the upper plug, and that "C" is the lower drain plug....am I right? I got confused because I saw the foreign object "A" up at the top and I don't know what that is. So which ones do I use? This diff is begining to whine and is a 3.07 with almost 258k on it....probably neglected by previous owners as well, I don't even want to know what the fluid (or whats left of it) looks like

Plus as you can see in the picture the whole bottom half is coated with a sludge...which I hope is not leaked out fluid

Also, what size Allen Socket is this? 12mm? or 13mm? I only have a 10 and I can see that its quite a bit too small....

tangofox007 · #2 04-21-2005, 09:48 PM

A is the vent.
B is the fill plug.
C is the drain.
Do not remove C before B.
14mm.

Palangi · #3 04-21-2005, 09:53 PM

14mm hex wrench, and those plugs are probably reeeeeeal tight.

rg2098 · #4 04-21-2005, 10:00 PM

Quote:

Originally Posted by Palangi

14mm hex wrench, and those plugs are probably reeeeeeal tight.

Tight is probably an understatement. I ended up swinging a 10lbs sludge hammer against the 14mm hex wrench to get that bad boy out. And that was after pulling every muscle in my upper body trying to muscle it out.

pawoSD · #5 04-21-2005, 10:00 PM

Thanks!

Yeah I'll probably use the breaker Bar with a 14mm allen socket

I hope they come out, we got a few quarts of Mobil 1 synthetic 75/90 stuff to load them up with (both cars). So far I've never not been able to get a bolt out of either of these cars with enough coaxing and lots of pulled muscles.....always had success after a while...

Palangi · #6 04-21-2005, 10:08 PM

I never heard of one that absolutely couldn't be removed, but sometimes it's pretty brutal. Be careful not to pull the car off the jackstands.

pawoSD · #7 04-21-2005, 11:20 PM

I was doing it with the car driven up on a progressive pile of stones and pieces of wood

Makes for a very solid base.... Step 1: 12cm thick block of concrete about .5 meters long, Step 2, 3, and possibly 4: Pieces of wood progressively getting higher. I end up with the car sitting on a stack of thick pieces of wood on a block of stone, so the car is as sure footed as if it were on the ground, then I chock the wheels.(the front ones, with steel chocks) For other stuff I use the jack stands and hydrolic jack.....but the small stack of stuff gets it high enough for me to work under there comfortably.....

Palangi · #8 04-21-2005, 11:27 PM

That's similar to my PoBoy system. I use a pair of steel ramps which run up to 2 rows of cement blocks. A 4x8 sheet of plywood down the middle is the perfect sized spacer + it keeps me out of the dirt. Perfect setup for this kind of stuff. Jacks and jackstands scare the hell out of me.

Lycoming-8 · #9 04-22-2005, 12:22 AM

There is actually a Mercedes wrench for this job. It used to come in the tool kit, believe it was in the one for the '68 220D. It is a sort of doglegged flat bar with one of the hex studs sticking out of the flat side of the bar at each end. Have used it for all of the rear end drain plugs and the manual tranny plugs as well. MB should have included this tool in the tool kit, but seems it was deleted some time after '68.

pawoSD · #10 04-22-2005, 12:31 AM

yeah when I was doing my cooler lines and mounts I got paranoid at times when I was pulling on bolts and stuff because the stands/wood on them would creak and make sounds

I agree I very much prefer a stack of solid objects to stands, even though its unlikely it'd come off the stands....mine are both 3 ton, meaning they can hold several times the weight of the entire car....so I do trust them when I use them, its just....the thought of the car slipping off of them thats scary.

babyjames · #11 04-22-2005, 12:52 AM

Grab ahold of something (like the rear bumper) and push on the allen (breaker bar, cheater, what-have-you) with your foot. I like good, old-fashioned cinder blocks, with jackstand chasers, and I try to leave my floor jack under something structural as well, just to be rediculously safe!

tangofox007 · #12 04-22-2005, 08:51 AM

Quote:

Originally Posted by babyjames

I like good, old-fashioned cinder blocks, with jackstand chasers, and I try to leave my floor jack under something structural as well, just to be rediculously safe!

"Cinder blocks" and "rediculously safe" do not belong in the same sentence!!!

SD Blue · #13 04-22-2005, 09:36 AM

If I remember correctly, Leathermang had a great method for removing those drain plugs without all that grunting and groaning. Do a search for differential drain plug and his name and it is fairly recent. I believe he used a jack and the weight of the car.

(Of course, depending on your age, you may have a desire to flex some of that excess testosterone.

)

riethoven · #14 04-22-2005, 09:41 AM

Sorry to hijack the thread! just one question paowsd - how did you put thoses arrows on the photos? What software is that? Please help a PC idiot!

d.delano · #15 04-22-2005, 10:35 AM

Start->Run->type in 'mspaint'

use the tools provided in this small built-in Windows application to draw and put text on photos

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