Need to know: w123 sedan and wagon - interchangable engine, drivetrain and rear susp? - PeachParts Mercedes-Benz Forum

300SDog · #1 04-28-2006, 06:54 PM

Found a decent (auto tranny) 300TD shell for free - engine and tranny already been pulled. My plan is to install the 240D engine and 4-spd from my parts car, doing a side-by-side.

My question is whether or not the w123 drivetrain of the wagon is identical to the sedan.

Yes, am aware the 240D driveshaft will be part of the swap to accomodate differences in automatic/standard tranny length, also paintmarked for perfect ballance. But does the 300TD wagon share the same driveshaft as 300D sedan? If so then no problem. Or do the wagons have longer wheelbase and/or ridiculously tricked out rear suspensions that are not interchangable. And can the hydraulic self-leveling device be swapped outright for what's on the 240D parts car? Ultimately am thinking Bilstein HD's for rear suspension, but dont want the wagon to sag if fully loaded.

I need to know this pretty soon because otherwise the freebie wagon shell will be gone soon.

Biodiesel300TD · #2 04-28-2006, 07:50 PM

The wagons have a self leveling suspension in the rear, which requires a pump on the engine block. The 300D engines do not have the mount for the suspension pump. So if you pull and engine out of a 300D you won't be able to run the SLS system on the wagon. It is possible to put typical shocks on the rear of the wagon, there has been lots of talk here about doing it. Search for wagon rear suspension or something of the like and you will have more reading than you can shake a stick at.
I believe the drive train is the same, but someone else may know for sure.

Benzcrusher · #3 04-28-2006, 09:23 PM

Yes the driveshafts are the same, both the wagons and the sedans have a wheelbase of 2795mm 110in. Two years ago I posted threads about transplanting a 300D NA motor and tranny from a '79 300D into an '82 300TD which had a blown motor. I converted the rear shocks with coil-over shocks. Since the swap I have put 32,000 miles on the car. Compared to my other '82 with turbo motor and working hydraulic rear suspension, the Frankenstine car is slow and is a little bouncy.
A 240TD was made for the European market, it will sure be slow. The wagon will have a 3.09 rear end, you'll want to swap the diff to a 3.47 (300D NA) or 3.69? (240D) so that you can have decent acceleration.

Bajaman · #4 04-28-2006, 10:02 PM

I am parting out an 80 TD. Just started it up today. PM me if your interested in the engine , tranny or both.
Baja

diesel don · #5 04-28-2006, 10:17 PM

I've heard some stories about converting the rear suspensions of TD's with shocks but never had the gumption to try it.

I ultimately got out of wagons for that reason. That was one complicated system plus expensive.

I like the simplicity of the sedans.

Don

JimmyL · #6 04-28-2006, 11:16 PM

Quote:

Originally Posted by diesel don

I've heard some stories about converting the rear suspensions of TD's with shocks but never had the gumption to try it.

I ultimately got out of wagons for that reason. That was one complicated system plus expensive.

I like the simplicity of the sedans.

Don

I politely disagree! There is nothing real complicated about a hydraulic pump, struts, accumulators (air cells) and a valve assy. It's really closer to a proactive brake system than something complicated. It's expensive if you ever buy the pump, struts or valve assy new, but none of us do that. Accumulators are about all you buy new, and they are close to the price of good shocks. It is not a system that seems to have many problems, and few if any folks who have converted away from SLS has ever been happy with it.

300SDog · #7 04-29-2006, 01:29 PM

Thanks for the replies. Am beginning to think I'd be biting off more than I can chew with this project. Replacing the driveshaft, pumpkin and entire rear end aint gonna be easy even with a shop at my disposal. Getting around the hydraulic pump is probly the tie breaker.

Benzcrusher · #8 04-29-2006, 03:47 PM

How much is the wagon parts car?

300SDog · #9 04-29-2006, 07:47 PM

The wagon is free but the owner will probly throw a 300D turbo engine in it, if I dont go for the 240D conversion. Its Euro version with LEATHER seats - swear to god real leather.

The hydraulic pump is located on cyl head of the pulled engine. He might have to swap heads to make it work.

Benzcrusher · #10 04-29-2006, 10:12 PM

Hell, you can't beat FREE! 123 leather is rare, up there with w123 heated front seats..

babyjames · #11 07-07-2006, 09:40 AM

To eliminate the SLS you just use Bilstein HD shocks, a fresh set of the longer rear springs for a W123 sedan, and the tallest spring-seat shims (don't they have four "bumps"?).

Sensitivity to small bumps is significantly less than w/SLS, but the highway ride and, more importantly to me, the HANDLING are far superior.

Then you can take the springs that came out of the wagon and put them on your sedan. DRASTICALLY reduced body roll. You won't believe the difference!!

Jay.