I heard the clunk one day, starting up a hill with a full car, then nothing until it blew out on a trip 6 months later.
Don't take it on a long trip until you figure it out.
Rob'85 300D, Garden Grove, CA
=
You guys in CA have me green with envy. I can't even find one of those in my area. I have a related question . My 85 300SD just developed an interesting quirk. I drove it a few blocks, parked, started it up again and backed out of the parking spot. At that point, I heard a loud pop. It did it again the next time I backed up. I haven't driven it since. It seems to me like a failure in one of the real axle joints that is allowing it to wind up, and then release when the car is reversed. Any other possible causes? I haven't noticed any thumping, grinding or other sounds of immanent failure. I'll jack up one wheel and see what happens when I rotate the wheel back and forth, but the differential action may not let me learn anything.
On Mon, Jun 27, 2016 at 1:57 PM, Nate vwnate1@yahoo.com [diesel_mercedes] <diesel_mercedes@yahoogroups.com> wrote:
[Attachment(s) from Nate included below]So ;
The final drive in my beloved Diesel Sports Coupe is howling at some speeds , not loudly unless I'm heavy on the throttle but it's annoying and one of the drive axle boots has failed , I think because of the various Diesel Fuel and oil leaks I've experienced .(rubber , be it real or synthetic doesn't like Diesel Fuel nor waste oil from Diesel engines) .
A bummer as I had both drive axles rebuilt a few years ago and they're dead silent but they're also the original Homeopathic typ , good for longevity , not good if the boots go bad and need replacing .
After changing the final drive oil a few times and adding magnets I cleaned the out side of it up and discovered it's a 3.07 ratio , Pic. # 1 .
I went to a local Pick-A-Part Junk Yard and found a 1984 Diesel Sedan , it had _one_ of the up graded annular drive axles , this meant I could get the $500 (price new from Mercedes) up grade drive flange and shims , clips , nuts , bolts and so on , all for the low price of the $23.95 axle , core charge included .
Such a deal !.
Then I found a 1984 W126 Diesel that had the correct 3.07 ratio final drive and tried to remove it , skipped one important step : _FIRST_ you must remove the outer end drive axle retaining bolt and knock the axle in wards until you can withdraw the outer splined end from the brake hub , then you can drop the final drive easily , remove it's derby cover , remove the retaining clips and with draw the axle .
I didn't do this so when I dropped the cover off the final drive to access and remove the inner retaining clips , I wasn't able to remove the axle as it was no longer extended fully......
Oopsafter struggling with trying to remove the entire final drive (it turns out you *must* remove the axles outer ends first
) , I gave up and hired a nice roving Mechanic guy to drop the entire rear subframe , even then we had to fight the final drive loose as I'd cocked it slightly to one side and the studs it fits on , are *very* tight in their holes .
Pic. # 2
So , now I had one very nice used 3.07 final drive and one good used annular typ drive axle in need of new boots , as long as I had to take it that far apart I figured might as well see if I could find another annular typ axle and the $pendy flange it needs too , replace both whilst I had it all apart abd be done with it for a decade or longer .
Off to LKQ's website to search for W123 Mercedes' , I found one , a Coupe no less in Long Beach but it'd already been there for TWO WEEKS and we were in the middle of a 102* F heat wave.... off I went and there it was ~
Pic. # 3
I crawled underneath it and Lo ! the final drive was there (wrong ratio @ 3.58) along with one annular axle and the flange , best of all , 1/2 of the hard work was already done ~ the entire thing was only hanging on by one splined end , I popped the cover off and knocked out the retaining clips and bought it for another $23.95 .
Pic. # 4
Pic. # 5 shows the clean and very good condition final drive in the wrong ratio , just to give you an idea of what I'm working with here .
So now all I needs do is order in four new boots from Mercedes Classic Center , clean and service all four CV joints , install the new boots and the new used 3.07 final drive , button it all back up and I'll be ready to go back to the endless exhaust smoking and spitting of oily drops on the back of the car .
Soon I'll break out my cylinder leakage tester and see what the heck is going on ~ I imagine I'm going to discover the boobs who rebuilt my engine , screwed up and it'll need at the very least , new rings if not new pistons too .
There's more , like how I figured out how to more easily remove the inner retaining snap rings but I'll need someone to hold the camera for that .
I also found a limited slip 2.47 ratio final drive in yet another W126 gasser but I don't know if my engine will loose to much power in off line acceleration ~ I *do* know it'd make my Coupe a dandy Desert Flyer and prolly raise my fuel economy noticeably but as what cost ? .
I don't want it to be any slower than it is now .
-Nate
--
Al Boucher
Posted by: Aleph93 <aleph93@ca.rr.com>
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