The trouble of the door opening limiter breakdown is to my opinion just as commonplace as the seizure of a sunroof or of an ignition lock cylinder – these are pretty common for an old Mercedes car. Usual symptoms of an upcoming trouble include stiff movement, squeaks, scratching noise and clicks that can be heard while trying to open or close the door. If you fail to pay attention to them (as many usually do), the limiter may stick open at a most undesirable moment – when you are in a hurry, or late at night on a parking lot far away from home, or in winter, or when it’s raining – in other words, in such a situation when the thought on any immediate repair work alone is unbearable. So don’t hesitate and replace the limiter as soon as possible. In some cases, however, it’s possible to avoid the replacement process and repair the limiter, and this is what I am going to tell about below.
The design evolution
The limiter design has undergone certain evolution. Figures 1 and 2 show limiters, token from the cars of the 1985 (blue) and 1989 (red) years of manufacture.
The difference is seen to an unaided eye: the latter detail is provided with the two additional side sliders located closer to the rod end. The third fixed position is most probably needed to prevent the door from quick opening. Also the detail has two safety spikes opposite to the rod axle mounting spot; yet their function is unclear.
There is also a slight difference in the length of the cylindrical axle of the rod as well as in its face end design. As a result, the plastic plugs that are inserted into the axle from both sides are also of different length, which basically makes them noninterchangeable, although the general axle length of the both limiters is equal.
The front site of the rod displays the manufacturing date including the month and the year as well as the rod lengths (which equals 100 mm for the W126).
Despite the difference both models have one same problem – they are not water-resistant thus being susceptible to corrosion (especially the bottom part) which is the only reason for them to fail to function properly.
At the moment the limiters are supplied with a plastic protection case. On figures 5-7 you can see the Meyle limiter with a butt axle and an original Mercedes limiter with #1267200615 (at the bottom, same color as the body) with and without the protection cover.
- Remove the inner door surfacing as well as the polythene film that is located between the surfacing and the inner door panel.
- Remove the inner disc that fixes the butt axle by pulling its tag (fig. 8).
- Carefully knock out the butt axle, remove it and free the limiter rod (fig. 8). Caution: do not loose the 2-mm plastic disc that is not supplied anymore nowadays.
- Screw out the three M6 screw-bolts that fix the limiter to the door. Two of them are located on the front-site and one on the inner door panel. After that take out the limiter threw the special aperture.
Carefully explore the guide tracks and fixing caves in the case as well as the condition of the plastic plugs and make a decision whether it’s worth repairing. If not, simply get rid of the old limiter – to my opinion, the further disassembling makes sense only if the corrosion has not created significant holes inside of the guide track (fig. 9) and the plastic plugs have no deformation marks.
If despite everything you have decided to move on, you should do the following:
- Unbend the fixing plate in the last hole of the body frame.
- Wrap the body frame end with some waste cloth and try to push the rod back along the body frame (this won’t be easy) by gripping it in a vice. The waste cloth protects you from an injury when the balls “shoot out” and also prevents you from looking for them around your garage.
- Remove the rod, having experienced the shot, unwrap the waste cloth, take out the balls, the coil spring and the plugs from the rod axle.
You can see that the corrosion has destroyed the ball chrome coating having uncovered the metal (fig. 10). The balls do not rotate anymore and simply drag along the rusty tray.
Thoroughly remove the remains of the old lubricant, dirt and rust from the inner surfaces of the body frame and then clean it with petrol or dissolvent. Rub down the rust surfaces and treat them with the rust penetrating solvent according to the manuals until the rust is completely removed. After they dry, cover the surfaces with a plenty of dense lubricant (lithol or similar).
But where do we get the new balls? The answer appeared to be simple and inexpensive. Thanks to our Chinese friends (or maybe even not to them) who manufacture elbow catches for that purpose containing original 15-mm chrome covered balls (fig. 11). You can buy them on any market for a couple of dollars.
The assembly work should be done in the reverse sequence. Insert the plugs, fill the rod axle with the lubricant to ½ of its volume, insert the coil spring and… I’d love to watch how you would be inserting the balls and the rod itself inside the body frame! And I’m not really sure for how long will such construction work.
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