One of the major vacuum leaks was the power brake booster. When the brake pedal was pressed you can hear a hissing sound inside the car indicating a tear in vacuum diaphragm. The check valve in the vacuum line for the brake booster was cracked. A re-manufactured brake booster has been installed and the vacuum line has been replaced with a non-OEM hose and checked valve. A new master cylinder has also been installed as its rear seal being bad was the cause of the brake booster failure. The brakes still need to be bleed.
The timing chain was found to be very stretched; 10deg out of time at the harmonic balancer and the timing chain tensioner was nothing more than a glorified spring, so the timing chain was very loose and flopped around. I have now installed a new timing chain via the "right-cam-sprocket-feed-method". All the nylon chain guides in the heads, the chain tensioner liner, and tensioner were also replaced. Not an easy task.
8 new spark plugs, distributor cap and rotor have been replaced as a preventive measure. The old ones looked well used. The spark plug wires that were on the car and had cracked insulation. A new set of proper spark plug wires made for this car has been installed. One of the things I did to my classic pickup is to use a piece of solid core spark plug for a coil wire. I am thinking about doing that here as I found it made the truck run very smoothly.
Because the car was running poorly when I bought it on account of the ancient 10 year old gasoline, 8 new fuel injectors were installed. No one in the location where I was living at the time had a gasoline fuel injector tester. I also replaced all the injector seats, and the injector seals. I also replaced all the tubes connecting the injector seats, which are related to idle control system, as they were all hardened and wouldn't seal. Use of BG Products 44K Fuel System Cleaner has had a positive effect on the fuel distributor. It is likely that simply running the car will be the best remedy here to get it running clean again, possibly with the aid of more 44K.
The tubes connecting the injector seat were made by URO parts. The walls on the tube were very thin and ruptured they have been replaced again, this time with Mercedes parts. No more URO parts will be installed.
The engine area has been checked for vacuum leaks. I have reinforced all the connections with small zip ties -- like hose clamps. I have installed 2 new check valves as the old ones were no longer operating like check valves. I did find the vacuum lines were not connected according to the Mercedes vacuum diagram. Those line are related to the emission control, part of which is missing, have now been eliminated -- caped off. The air pump has also been removed and boxed up as it was seized up anyway. The rest of the vacuum lines now conform to the Mercedes vacuum diagram.
The Idle Control Valve was checked and found to be good. The Idle Control Valve received 2 new connecting hoses as the old ones had hardened and were leaking. As mentioned above all the other rubber hoses for the Idle Control system have also been replaced. I have re-flowed the solder joints on the Overvoltage relay and the idle control module. Further troubleshooting will be conducted once the engine can be started again and the engine is still idling high.
All new heater and radiator hoses have been installed as a preventive measure. I'm sure the heater hoses were the original hoses for the car, as a couple of them were on the brink of rupturing. The flushing of the cooling system flush will take place soon using citric acid. There is no actual radiator shop in my area so I couldn't remove my radiator and have it boiled out.
The engine oil was pitch black when I purchased the car. It looked like something out a diesel engine. An oil system flush is setup. Walmart 5W20 oil is being used along with a quart bottle of Marvel Mystery Oil -- an engine cleaner. This mixture has been poured in after draining out the old black oil. The oil filter canister contained a black filter and a layer of grim in the bottom that required scraping with a screw driver to remove. The mixture was drained after 100-200 miles only around the local area where I can keep the engine speed down. A second clean out was performed with 10W30 oil and Marvel Mystery Oil The engine was run for around 500 miles this time and was much cleaner when it was drained.
All of the fuel lines under the hood and the rear of the car at the gas tank have been replaced. I used high pressure fuel injection hose and securely clamped it with clamps designed for fuel injection systems. The lines inside the enclosed gas tank area are a project for another time. All the steel lines were blown out with 100# compressed air. A new Bosch fuel pump and accumulator, and a new fuel filter have been installed as a preventive measure. The tank was missing fuel screen on the bottom tank plug. The plug was present just no screen. I believe it was completely removed by a previous owner when it clogged up. I new plug/screen has been installed to keep large debris from clogging the fuel pump.
While investigating the inside of the tank with an inspection mirror and flashlight I found the the previous owner or their mechanic did the amateuristic repair of punching a hole in the side of the steadying bowl with a screwdriver and hammer, rendering it useless. The steadying bowl is an important part of the fuel delivery system. They did this for reasons which I cannot understand as both the fuel return line and steadying bowl venturi were all clear and open. I have plugged the hole using a patch made from a shop towel and saturated with fiberglass resin based body filler. I inserted it into the hole with a screwdriver tucking into place as firmly as I could without tearing the shop towel. Because I could touch the hole through the drain plug hole I finished tucking the saturated patch into place with my finger. I left the patch to dry overnight with the gas cap off the tank and gas door hanging open. The next morning I tried to pull the patch loose with my finger but found it to be securely in place and hard. By the morning following that I had the fuel pump/filter assembly mounted and connected, after which I poured 5 gallons of fresh ethanol-free premium gas in the tank.
Under the car
While looking at what I will need to do to replace the fuel filter I glanced at the exhaust and noticed that it was wired in place with bailing wire and the rear muffler is rusted through. Even though the muffler was still quiet it would have never pass Utah's vehicle safety inspection. A new Italian made Ansa replacement muffler has now been installed with a full set of proper hanging rubber. The replacement muffler had flares on the intake pipes so it would slip over and couple the existing pipes. It required sawing off the existing pipes in just the right places so the muffler would hang in just the right place.
The following year I have now replaced the remaining exhaust system from the head pipes back. The catalytic converter had clogged as the insides had melted. The rear most muffler is being reused as it is only 2 years old.