Alerts

Kent is hard at work on his new series of advanced D.I.Y. mechanic series of manuals. The challenge for him has been trying to make the advanced technical side of the information still understandable to the average home mechanic. For example, explaining how to use electrical testing meters to test the function and health of a diesel pre-glow system is not an easy task. Describing how to fine tune the vacuum adjustments on a diesel automatic transmisson is even more difficult.

The new manuals will be printed and wire bound in a larger format (8.5 x 7 inches). This will allow room for more charts, schematics and larger pictures. Knowing that these manuals will be handled often, we are adding a plastic cover to help minimize grease spots.

The newer flex disks on the 201 and 124 chassis are designed a little different from those found on earlier models. They do not have the same tendency for catastrophic failure, but they are prone to other problems like clicking noises and drive line vibrations. This is becomming a very common problem as these cars get older.  Failure has proven to have more to do with age than vehicle mileage.  Just recently I had a 1987 190E come into the shop with only 80,000 original miles and the front flex disk was totally shot.  Click to read more.

Flex disc failureNew flex disc

I am seeing a lot of flex disk failures on the 70s and 80s daily driver 114, 115, 116, 107. 123 and 126 chassis. The disk that usually fails is the front one, and when it does the front short section of the drive line flings around under the car and causes other damage in its wake.

If your 126 sedan or SEC coupe is making front end clunking noises when you brake or go over bumps at slow speed you most likely need to replace the bushings where the lower front suspension guide rod attaches to a body sub frame casting. The purpose of the rod is to prevent the front suspension from moving aft under heavy braking.

Many 123 and 126 chassis owners don't know there is a filter inside the Power Steering pump reservoir. Consequently this filter never gets changed and when it starts to become plugged your power steering may become sluggish or squeals and may even damage the pump or steering box. Change the filter and fluid now for longer life and better performance.

On most Mercedes from the early 70's up to the late 80's (including 114 115, 116, 107, 123, and 126 chassis cars) with independent rear suspension it is not uncommon to hear clunking noises under the back of the car while you are driving. Sometimes finding these clunking noises can literally drive you nuts. Do not just throw parts at the noise until you actually find the cause. There are a number of things that can cause clunking around the rear end while you are driving, but one of the most common is a worn ball socket in the one of the sway bar links that attaches to the outer hub on each side of the rear end. Upon a casual inspection you may not see the wear in these links and of course if it's under tension you will may be able to feel it either.

As the 616 and 617 diesel engines age, I am seeing an increasing number of worn out camshafts coming into our shop. In my humble opinion the cause of this is usually due to lack of frequent oil changes. Excessive valve clearance may also be a contributing element to the problem. It all begins with minor scoring of the cam lobes. Then over time the wear increases to scoring on the rocker arm and eventually the cam tip itself will wear to a sharp point. As this happens you will notice a gradual loss of power and the engine will begin to smoke more.

Since the plastic tank radiators of the 80’s are notorious for breaking off their plastic necks (can ruin your day and your engine!) it is best just to replace the old radiator with new or reinforce the top neck of your current radiator.

For those of you who are not already aware of this potential for trouble, my recommendation is that you do not under any circumstances use any type of silicone gasket adhesive on any part of your engine whether diesel or gasoline. I cannot express my dismay at how many times I have seen silicone particles running loose inside an engine. It can often lead to major engine damage.

If you lose your timing chain you will destroy your engine. The pistons will come up and hit the valves and at speed can push the camshaft(s) right through the valve cover(s). There is no set recommended mileage at which you should change it.

Like many things on the diesel engine, the transmission cooler lines are subject to much vibration. The clamps that support them along each side of the engine pan have plastic inserts that prevent chaffing. Over time these plastic inserts break out and all you have left is a metal clamp rubbing against the aluminum tubing.

Along with radiator neck failure, the rupture of one of the large oil cooler lines on your diesel engine can easily ruin your engine. When one of these lines goes you can lose all your engine oil in just a few minutes. If you are driving and not watching your oil pressure gauge you can destroy the engine bearings in short order.

If you lose your timing chain you will destroy your engine. The pistons will come up and hit the valves and at speed can push the camshaft(s) right through the valve cover(s). There is no set recommended mileage at which you should change it.

In the last few weeks we have seen two instances where the throttle has stuck open on 123 diesels. This can be very scary and you may need to have the where-with-all to turn the engine off while driving to keep the engine from over revving. This can make it hard to steer and brake! In most cases you can put your toe under the throttle pedal and pull it back. Best to just prevent it from happening in the first place.

If you own a 1981 to 1991 123, 107 or 126 chassis and have not heard about the mono-valve then this alert should be a real help. This little valve controls the amount of hot water going into your heater core. The seal for the valve is made of rubber. With age this rubber splits and will cause your heater to go wacky. It will generally get hot when you want it to be cold and in some cases it acts like it has a mind of its own. Failure of the mono-valve has often led to some big repair bills for the unknowing. This part is very inexpensive, can easily be replaced by yourself, and in 7 out of 10 cases will most likely solve you sporadic heat problems. Click here to order our mono-valve repair kit with instructions.

We have seen or heard of enough unecessary brake booster replacements recently that we decided it was time to put up an alert for our customers. If you have been experiencing a hard-to-press brake pedal and have checked your vacuum source or vacuum pump output - DO NOT assume or let your mechanic tell you you just need a new brake booster.