Mercedes R107 450SL High Quality Aftermarket Tail Light Lenses & Seals

Depending on where your Mercedes has spent most of its life, the tail light lenses might very well be cracking or simply dull and or discolored. The rubber weather seal is a whole other story.

Since November 2017, I have been on the SL Shop waiting list for the first round of aftermarket Mercedes R107 tail light lenses and it was worth the wait. Admittedly, I was a bit skeptical, but seeing is believing and this is an excellent reproduction. The lenses appear to be a very good quality and the fit is just as the originals. As with any product, time will tell if they are as excellent as the originals. The colors are very deep and rich which is often a shortcoming on aftermarket lenses. 

With the lenses I also purchased the weather seals from the SL Shop. These seals have a perfect fit and first rate quality in addition to feeling every bit as good as the Mercedes weather seals for a fraction of the cost. Again, another several decades will be the true test, but for now it couldn't get any better.

The SL Shop, located in the UK, has provided me with numerous parts thus far for the R017 restoration. I am not only very pleased with all of the parts, but am just as delighted with their dedication to customer service. While I source many of my parts directly from Mercedes, I will continue to purchase from the SL Shop on excessively priced parts or aftermarket parts no longer available from Mercedes.

The following images show the original 43 year old Mercedes taillight along with the new after market version. NOTE: When reinstalling, DO NOT over tighten as the lens assembly can crack. The bolts are to be snug, not tight. In addition, do not force any of the parts together. They fit very snugly and should be eased back in place.

The M-B original has faded over the years from being parked in the desert for 8+ years, but remains in remarkable condition.

Every detail is expertly replicated

Assembly as it came out of car before cleaning for reinstallation.

W123 Transmission Vacuum Diagram & Shift Issues

If your W123 diesel has shift issues, there is a very good chance that the transmission is just fine. 

There are several things to check, and most of them are vacuum related. Any part of the vacuum system that is failing can and will cause disruption to the transmissions ability to shift properly

SYMPTOMS:

Transmission quickly progresses through gears (1-4) from a stop and does so a bit sloppily. Or perhaps there is flaring between particular shifts. Or perhaps, the transmission is not wanting to shift at all or shifts very late.

These symptoms should be checked at once to avoid potential damage to the transmission. The following check list will help determine what might be going wrong.

CHECK LIST:

Transmission Fluid: Drive car for at least 15 min. to make sure engine and transmission are at full operating temperature. Check fluid level with gear selector in "N". Do not use "P" as you will not get an accurate reading. NEVER OVER FILL the transmission.

Vacuum System: Must be in perfect working order. Even the smallest leak can cause havoc on how the transmission shifts. If need be, isolate the leaking sections by disconnecting them and capping off at the location. Remember, if the vacuum is to high the transmission will want to shift to quickly, if the vacuum is to low, the transmission will not want to shift at all. The transmission vacuum system for the Mercedes 240D is as follows:

The VCV and Transmission vacuum modulator are no longer available from Mercedes-Benz.

Main Vacuum Circuit Components

Change over valve (located on top of valve cover) This part breaks regularly!
Vacuum control valve (VCV)
Vacuum modulator (located at side of transmission)
Vacuum Dashpot (check valve) green in color

ADJUSTMENTS:

If your transmission fluid is at a proper level the next step is to ensure your vacuum system is in perfect working order along with the throttle linkage being properly adjusted

Once you are sure the fluid, vacuum and linkage are in good working order, the next step is to adjust the VCV valve. 

HOW TO ADJUST THE VAVLE:

1. Loosen the VCV valve retaining bolts (no need to remove)

When bolt has been loosened, screws and hose removed, gently remove cover.

2. Remove side cover

3. Using a wrench, turn the nut on the end of the spring counter clockwise if your transmission is shifting early and clockwise if shifting late. NOTE: To make this adjustment you MUST hold the throttle linkage in the closed position while turning the nut. It is also important NOT turn the the adjusting nut more than a few millimeters at a time. If you over adjust, your transmission will not shift out of first gear. 

Leave the cover off while test-driving the car to make it easier to make adjustments while you are on the road.

If this adjustment still leaves your transmission shifting a bit late or early the next step is to adjust the transmission vacuum modulator which we will cover in a subsequent article. 

Mercedes Vacuum Diagram

I developed the following digram for the 1975 R107 Mercedes-Benz 450SL so I would have a complete guide should anything go wrong after the car is put back together. This digram does not show the engine vacuum. 

LEAK DETECTION:

When diagnosing leaks in the Mercedes vacuum system, a vacuum pump with gauge is mandatory or should you have a smoke machine on hand, that would be the ultimate way to go. 

First, start by checking the vacuum tanks for leaks. One is located directly under the front fender on the passenger side above the wheel (LHD). This tank supplies vacuum to the central locking system and cruise control. The other tank is located behind a panel to the left of the emergency brake. This one hold vacuum for the climate control. 

Unscrew plastic panel and slide away to expose tank. To remove tank and panel, e-brake assembly must be removed.

Passenger side U.S. model

The vacuum tank for the climate control should not have any issue with deterioration other than the rubber grommet that seals the tank where the vacuum line enters. This part is still available through Mercedes.

The central locking vacuum tank however is susceptible to damage and deterioration as it is open to the elements just above the front wheel. Both the tank and grommet are still available from Mercedes.

A good test to perform to insure proper vacuum is maintained, is to pump up the tank down to 10 mHg. Make certain that your connections are leak free and your gauge is good. The tank should hold vacuum for at least 48 hours without any loss of vacuum. Conduct this test on both tanks. I personally would not recommend using the smoke machine to test the vacuum tanks. 

Finding leaks in the system is not complicated, but time consuming. Most often it is the rubber connectors that dry rot and begin to leak. If you have the original system, it is best to test each section of vacuum line by disconnecting, capping and testing one section at a time. The digram will show how the system is divided up throughout the car.

Vacuum leaks are also very prevalent at the diaphragm type locking modules. At 40+ years, the rubber diaphragms are quite crispy and will likely leak. These include the heater tap, fresh air flaps at cowl, passenger side door, fuel flap, and trunk. The passenger side door lock, and trunk lock on earlier 450SL's are no longer available from Mercedes.

Other points of leakage are the driver door lock master vacuum switch and the vacuum switch at the A/C switch. Both switches are identical in function but are designed differently. Both are available from Mercedes.

Vacuum for A/C Switch is still available through Mercedes-Benz

The final potential point of a vacuum leak is the Ford-Philco cruise control unit. The cruise control unit is most likely under the dash behind the glove box on a U.S. car.

It is also wise to change out any check valves. They are located under the hood at the fire wall driver side. Original check valves are black and green while the new ones are blue and black. These are unmetered.