Transmission Mount

Since the day I bought this car there's been an odd vibration when the vehicle is under load. It is most noticeable when the weather was colder and the car is driven uphill. The vibration goes away at higher speed (when the load on the transmission is removed). At first I thought it was a flex disk issue, or carrier bearing but those appear to be in good shape. Looking at the transmission mount with out a flashlight and a pry bar that appears to be in good shape also.

 

After closer inspection with a brighter light and a pry bar it became clear that the rubber mount has deteriorated. I was able to wedge the pry bar under the transmission and move it up and down about 2 inches. Hopefully this is the only source of the vibration.

 Close up of rotten mount.

I ordered a new mount online, and it arrived today.

Looking at the new mount its clearly apparent that this is not the same mount that is in the car. The mount from my car has a round hole for the bolt to pass through which is securely encased in rubber while this mount has an oval hole which is free to move around and is only connected by two strips of rubber at the edges.

I recheck my order, Mercedes-Benz Home > 1983 Mercedes-Benz 240D Base Sedan > Transmission & Clutch > Transmission. There is a note next to the part which reads Fits Manual Transmission. I then cross reference that with Mercedes-Benz Home > 1983 Mercedes-Benz 240D Base Sedan > Transmission & Clutch > Automatic Transmission. Interestingly enough the manual transmission and automatic transmission mounts have the same part number. Guess I'll need to contact customer service regarding my order.

Though I don't have three correct replacement yet, I had some time to pull the old mount from the car and get to see the condition of it. 

Shifter and Linkage

 

Above: Three linkage rods whose purpose is connecting the shifter to the 4 speed manual transmission. 

There has always been quite a bit of slop in the shifter and often when shifting from second to third gear you'd find yourself in a place I called upper third where the shifter seemed to travel farther towards the firewall than should be possible and it felt like all connection to the transmission was lost. Missing a shift in traffic when driving a car that makes about 45hp to the wheels is not acceptable. 

In the eyelets at the end of these shift rods are nylon bushings. Or should I say there should be nylon bushings. One of these bushings was missing from my shift rod and I ended up replacing it along with the others which seemed to correct the upper third problem. Note that there are also 3 rubber bushings on the transmission side of these rods. Mine were in good shape.

Shifter:

Though the upper third problem was resolved it was still difficult to feel the difference between the car being in neutral or being in gear. I removed the console and the four bolts holding down the shifter assembly.

Above is the shifter assembly removed from the vehicle. The photo is from the left side of the assembly. This is the side that would be closest to the outside of you right knee as you drive were you driving in North America. Inserted in the center hole of the assembly is a long spring. The spring is retained by a plug which I've photographed in the below picture. This plug was about to fall out the side of the shifter assembly. The only reason it hadn't done so was because while in the car the plug was pressing up against the inside of the center console.

Above: Deteriorating plug with metal washer.

I discarded the smaller pieces and tried to reinsert the plug. Two things are causing this to fail in my opinion. The first, with pieces broken off, there is no longer the required surface area remaining on the plug to maintain enough friction against the walls of the shifter assembly to retain the spring pressure when the operator moves the shifter to the left. The second, over time the rubber plug has stiffened, and shrunk.
TLDR; Plug is old and won't stay in when shifter is pushed to left.

 Above: Worlds worst cotter pins?

My solution was to drill 4 holes in the plastic housing of the shifter assembly with a Dremel, and insert copper wire to retain the plug. This seems to work on the bench as well as when bolted in the car. Though I haven't actually driven it yet, shifting the car in the garage feels like shifting other cars from the 80's. Which is a huge improvement of what it felt like before. My question is, why didn't Mercedes put a snap ring at the edge of this shifter assembly to retain the plug?

After installing this I found that it will not work. The cotter pins position the spring too far in towards the shift lever. When trying to shift into reverse, the spring becomes fully compressed and the shift lever is unable to move far enough left to slide into the reverse position.

Headliner

Some people stay away from anything having to do with the headliner. Before this, I had never repaired or installed a headliner. Usually I try to find a write up on a forum or pictures someone else has taken before I start a project. This is especially true when I have no experience in the area. I had no such luck sourcing any sort of tutorial.

I tried to find a picture of the original headliner, but it appears that I never took one. As I write this it occurs to me that I should have taken way more pictures. Just imagine the disgustingly dirtiest sagging piece of vinyl you can. Some rips, some stains, (how does someone stain vinyl?) flopping in your rear view mirror when you check to see how many people are in line behind you on that hill.

Mercedes used no glue (or so it appears 31 years later) to hold up the headliner. There are plastic strips which are heat welded to the edge of the vinyl. These attach to a metal lip underneath what’s left of my door seals and under the stainless steel trim of the sun roof. On the door side, they are clipped in place by extremely sharp metal clips, and on the sunroof side they slide under metal tabs and are pinched down by the stainless trim as it is screwed in place. At the back of the sunroof a cardboard strip pressed into a slot holds up the vinyl, and at the of the roof a metal bow with rotted rubber bushings used to hold tension in the rear of the car. The headliner is then tucked up under the rear windshield gasket. Removal is simple. With the headliner out and mostly intact, I have a template from which to build my new one. The above picture shows my new fabric, and the process of attaching the salvaged plastic strips from the old headliner. As of now the hood of the Mercedes has been replaced by a proper work bench. 

Purchased and learned to operate a new machine as part of this project. 

New headliner ready for install.

An assistant is helpful during the install of the headliner.

The center of the headliner (back of sunroof) was held in place by a cardboard strip about 15mm wide. The vinyl was glued and wrapped over the cardboard and then slid into a slot behind the sunroof opening. The cardboard was decomposing and fell apart in my hands when I attempted to remove it from the old vinyl. I knew I’d need to fabricate something to replace it, thought about gluing wooden dowels together, using some type of wood that could be cut on a table saw, but ultimately ended up purchasing a flat metal strip of aluminum from the hardware store. With some finesse (hammer), and help from Charlie the fit ended up being perfect. The strip is visible in the above picture on the right.

 Final product installed! Clean and fresh. no more nastiness hanging above my head. 

Blog begins

The blog title birthdaybenz was decided based upon the fact that the vehicle manufacture date of this car coincides with my birth date. I'd been looking for a 240D for a few years when I purchased this one from a kid in Saratoga Springs, NY. The story was that he had it shipped up from North Carolina, only driven it over the summer, and had nowhere to store it while he returned to college. The lack of rust anywhere on the car backed up his statement about North Carolina and cleaning the car later I would find a Durham library receipt. Though mother nature had been easy on old Ben in its 31 years some of the owners had not. There are many mechanical issues resulting from lack of maintenance. This car is far from being what it was rolling off the assembly line in Germany. I hope to use this blog to document the process I go through as I remedy those issues. 

The above photo was taken at sunrise in the mountains North of Asheville, NC.