W123, Electrical

differential gear ratio changing speedometer function?

I am excited to install the taller gearset differential, purchased from mercedessource, in my 81 300D. I'm wondering if the new gear ratio will affect the speedometer function. I have an opportunity to acquire a good speedo from a turbo if its necessary. Thanks...

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W123

starting problems

I ahve recently been given a 1980 300d gold wagon, it is not running, why? ...I have replaced fuel filters except for the tank one also return lines, glow plugs, glow plug relay did a valve ajustment replaced battery... the motor cranks over and seems like it wants to catch but nothing what could this be ?// any ideas would be alot of help

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W123

300 D Valve adjustment

I purchased the Mercedes Source Valve Adjustment wrenches and Manual soon after purchasing my first Mercedes (1984 300 D). And, faithfully, the valves have been adjusted ever since. ....Until today.. After adjusting 9 valves, the tenth one will not adjust. It is the exhaust valve on cylinder #2. I can't get the adjustment past .008in. Does this mean that the valve or seat is worn beyond tolerances? Or, am I missing a 'simple' solution? cory

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Is BioBor the solution?

Hey there, So I've got an '84 300D Turbo, it sat for a bit (couple of weeks) with a half-full tank of B99, which then gelled in the cold Seattle weather, so I added some Diesel to it. Now it's got tons of black stuff in the pre-filter. I'm told this could be from condensation. I've literally been changing the quickly filling filter out every couple of times I drive it, to be safe. I'm not driving far, and it gets pretty black in those couple of trips. Sigh. So.... I read a few other things & places, and it seems this is an algae (fungus?) problem. I also read I should get various Biocides, and ended up with BioBor. I haven't added it to the tank yet, and have a couple of questions. If anyone can help I'd appreciate it. There is about a 1/4 tank in there now, should I:

Chassis Model Number

W123

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difference between long block 300d 1976 and 300cd 1978?

I was told that the long block from a 1976 300d could be assembled with the rest of a 300cd engine and there would be no "issues". At the very least I am seeing that the oil pressure hose will need an extension (the oil filter is under the fuel pump in the 76 300d). However, I am also noticing that the injectors and fuel pumps for the 2 vehicles are different... Does anybody know what issues I might encounter if I tried this 300d block with the 300cd valve head? Is this a terrible idea?

Chassis Model Number

W123

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The Injector line at the Firewall - You know, the one with the nail it.

Hi Everyone, Just want to first also throw my 2 cents in that this is the best Mercedes Site - period. All books and tools I have received - work, so please do shop here. Also, I have found things generally are easier to do than you expect.

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W123

Alternator Belt 'problem' ... 1984 300Turbodiesel...

Since I upgraded my glow plug relay to the type of relay that leaves the glow plugs on for a few minutes after start up, the alternator belts have been squeeling until the relay shuts off. I would like to put in a solonoid on the power supply to the relay with a momentary on button on the dash... But, in addition to that, I simply need to tighten the Alternator belts. It seems an easy thing to do on a car like this, which is so comfy to work on, but I can't seem to get the job done. It seems there should be a bolt, or a nut, to loosen behind somewhere, then turn the long, skinny hex shaped thing, and then tighten up the whatever. I can't find the bolt or nut, or whatever!

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W123

Small vacuum lines

I recently purchased a 79 300TD wagon. I have discovered many hidden problems with the car since I purchased the vehicle. The main one is the discovery of a 3" hole behind the battery and tray. It was hidden by a poor fiberglass patch job and the battery.This has been leaking into the car and sitting on the rear passenger floor boards. The floorboards are also rotting and hidden by rubber undercoat. Anyhow, when I bought the car I knew it needed a new heater servo and amplifier.

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