Mercedes-Benz W123 And R107 DIY

Mercedes-Benz W123 And R107 DIY

The Mercedes-Benz VDO W123 Tempomat cruise control is now going on 42 years of service for the first years of production. Or perhaps it is no longer in service due to mechanical failure. These units, based on the research I have done, are pretty robust and are serving a good long time. That said, my 1981 240D with the bellows style VDO Tempomat actuator has been baking under the hood in the desert for many years and is finally not holding proper vacuum. 640, make sure it is not the amplifier (the brains) under the driver side dash or a vacuum leak elsewhere. The amplifier is subject to intense heat and vibration and they do get fickle with age. Several symptoms of a amplifier going bad is being able to increase your speed using the cruise control lever but not being able to set that speed once you let go. Other scenarios include the cruise control cutting out while engaged. I have already replaced my control unit with a remanufactured unit several months back as new units are not available from Mercedes.

Once the cruise control began working, I realized it had probably not been used in many years and the actuator began to malfunction after several trips on the highway. The symptoms: Once the speed was set, it would steadily lose it a few miles per hour every several seconds. Either the Tempomat was losing vacuum due to a dry rotting bellows or the internal vacuum/vent switch was not engaging properly. Either way, in my case, it was time for a new unit as I knew I did not have any vacuum leaks. The replacement of the actuator is not complicated at all, but one that will require a great deal of finesse to remove the bowden cable, if you wish to save the cable. While there are a number of NOS actuators available from Mercedes, there are evidently only two bowden cables remaining in the global Mercedes stock. While the cable is not fragile, all the plastic clips that are necessary to keep the cable in place are! If you break any of these clips the cable will not function.

Disconnect the vacuum, and vent lines along with the electrical plug. Now is the time to make sure no vacuum hoses or rubber connectors are failing. Disconnect the three plugs show in the photo. The gray nut for the vent line is plastic! Remove the nut holding the actuator in the bracket. Carefully release the bowden cable from the throttle linkage (valve cover area). Remember, the plastic clips are very brittle and are ready to crumble. Gently using needle nose pliers will work well. Unscrew the plastic threaded adjusting "nut" and once again using the needle nose pliers release the next section of the bowden cable. Push the cable toward the actuator to give a bit of slack to remove the next clip. This clip is awkward to remove and is too ready to fall apart. Go slow and gentle. Unscrew the three screws at the actuator retaining plate for the bowden cable. Give yourself enough slack for room to work. With the cable removed, the installation process is the reverse. The following steps are for the W123 second generation diesel models only! To adjust earlier models, W115 and W123, please refer to the Mercedes Service Manual. Adjust the cable. If the cable is not properly adjusted according to the Mercedes service manual the cruise control will not function properly. Make the following check and adjust cable length as necessary with the plastic threaded adjusting "nut": Press and hold the emergency stop lever (diesel) in the off position and check the slack of the cable.

Several safety features including forward collision warning and automatic emergency braking come standard, but buyers have to pay extra for adaptive cruise control, lane keep assist, and even blind-spot monitoring. Considering the X4鈥檚 coupe-like roofline, the designers also deserve credit for giving rear passengers more room than you鈥檇 expect. There鈥檚 one more much-appreciated inch of legroom than before and enough headroom to accommodate most passengers. With the rear seats down, the 18.5-cubic-foot trunk opens up to offer 50.5 cubic feet of cargo room. That鈥檚 not quite as much as the GLC Coupe has, but it鈥檚 a small improvement over the outgoing model. Under the hood, buyers get their choice of two engines. 51,445 X4 xDrive30i uses a twin-turbocharged 2.0-liter I-4 good for 248 hp and 258 lb-ft of torque. 61,445 X4 M40i, and you get a turbocharged 3.0-liter inline-six that makes 355 hp and 365 lb-ft. Both engines send their power to all four wheels via an eight-speed automatic transmission. The 2.0-liter doesn鈥檛 feel especially quick, but it should be more than adequate in daily driving situations.

Even though it鈥檚 the base model, the X4 xDrive30i will also hold its own on a winding back road. It鈥檚 no sports car, but with a standard M Sport suspension, it鈥檚 competent enough in the corners. Anyone with cornering on their mind, however, will want the X4 M40i. That extra 100-ish horsepower makes it significantly quicker than the four-cylinder model, hitting 60 mph in a claimed 4.6 seconds. Add in the larger brakes, adaptive suspension, and the optional M Sport differential, and you have a surprisingly enjoyable corner carver. The crackling sports exhaust is just a bonus. The brake pedal is less firm than I鈥檇 prefer, but the brakes themselves are strong, and the tires have plenty of grip. The paddle shifters deliver quick shifts, but the transmission programming is also smart enough that you can usually leave it to its own devices. Inflate the adjustable bolsters, and the seats do a good job of holding you in place, too. And although it initially wants to understeer, if you really push it, you can even hang the tail out for a well-controlled power slide. The X4 M40i wouldn鈥檛 be my first choice for track duty, but it offers the kind of hop-in-and-go fun that would make errands more enjoyable and a quick trip to the mountains exciting. When you need a quiet, comfortable commuter, Comfort mode is a button press away. No matter how sporty and well-rounded it is, some people will still dismiss the X4 as just an uglier, less practical X3. That鈥檚 fine. The X4 isn鈥檛 for them. But the fact that something isn鈥檛 for everyone doesn鈥檛 mean it isn鈥檛 for anyone. Buyers who like the X4鈥檚 styling should enjoy the driving experience, too, and those who don鈥檛 can still buy the X3.