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Discussion Starter #1 (Edited)
Hey guys, just wanted to introduce myself. My name is Glenn, and I'm coming over from the BMW game, and I currently have a 1985 300D turbo diesel. For any of you familiar with the BMW side of things I am coming over from the e34 535, so I am guessing they are some what comparable. I have two questions, and I cant seem to get the search function to work on my computer, so I apologize if these have already been answered before. My first one is the locking system for the trunk. I turn the key for the drivers side, and the trunk doesn't unlock. From what I saw, this car runs something similar to the BMW air lock system where the drivers door unlocks and locks all of the doors with the key turning. Please correct me if I am wrong, I am completely new to the Mercedes game, so everything I know will come from what my eyes tell me, and what I learned about cars from my two e34s. If I have read correctly, there is supposed to be some sort of vacuum hose under the first aid kit that comes into play with unlocking the trunk manually? I'm a little fuzzy on this.

My second problem is with a belt breaking. From what I understand this car sat for a year when the previous owner passed away. So I imagine this might be the first of many belts to break due to dry rotted rubber. The belt shows signs that it was just pulled to hard and snapped. No cut or slicing indicators at all. The belt connects to the alternator and something else. It appears to be about 3 feet in length. I wish I could give you more f a description, but since I know nothing about diesel engines I'm lost. I am semi-mechanically knowledgable in gasoline engines, so I can probably figure it out if you guys give me an idea what to look for. If this helps, I see the pulley on the alternator has two slots for two belts. Its the belt closest to the alternator that is broken. The other belt, from what I can see, the one thats still working, and farthest from the alternator, touches three pulleys in total, and the one thats broken touches two in total. I wish I could be more descriptive, but like I said, diesel is a whole new ball game for me. I know enough to know I don't know anything.

Thanks for the help, and if there is some sort of FAQ thread, I love to read anything to become less ignorant, so please link me to it.

Edit: Does 300D have a signifigance in classifying the car? Like theres a 3 series, 5, 7, etc in BMW, does Mercedes have something like this? I'm guessing 300 means a 3 liter engine, and it's a D class meaning a family sedan? Also does mercedes classify the era of car with a number letter combination? Like BMW runs the e sets, like the e30, e34, e36, etc. Just trying to become more familiar with this car.
 

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Hey, keep your trunk to yourself, and your belt buckled up!:D

Welcome to the MB Club!

OK, externally a diesel is only distiguishable from a gasser inasmuch as it doesn't have spark plugs. Also, a diesel has a vacuum pump, since it generates very little vacuum in the intake manifold.

On the W123 Diesels (which is probably what you have) there are two or three sets of fan belts. One drives the alternator and water pump - if it snaps, you'll know by the charge and brake light going on simultaneously - another drives the power steering, and the third drives the aircon.

The trunk lock sits in the trunk, at the back of the vehicle, nowhere near the first aid box. The central locking, as well as the diesel's shut-off, headlight dipping and brake servo, work on vacuum.

Mercedes's series numbers are three numerals e.g. 123 Series. C123 means coupe, W123 means sedan ("Wagen") and S123 means estate/station wagon of the 123 Series. 300 means 3.0 lt engine, D means diesel, E after three numerals meant fuel injection and E before three numerals means E-class (Executive?) There used to be only two series of cars, now there are many.

The N/A diesels used only one fan belt to drive the alternator and water pump, while the turbodiesels used two belts.

Hope this helps.
 

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Discussion Starter #3
Hey, keep your trunk to yourself, and your belt buckled up!:D

Welcome to the MB Club!

OK, externally a diesel is only distiguishable from a gasser inasmuch as it doesn't have spark plugs. Also, a diesel has a vacuum pump, since it generates very little vacuum in the intake manifold.

On the W123 Diesels (which is probably what you have) there are two or three sets of fan belts. One drives the alternator and water pump - if it snaps, you'll know by the charge and brake light going on simultaneously - another drives the power steering, and the third drives the aircon.

The trunk lock sits in the trunk, at the back of the vehicle, nowhere near the first aid box. The central locking, as well as the diesel's shut-off, headlight dipping and brake servo, work on vacuum.

Mercedes's series numbers are three numerals e.g. 123 Series. C123 means coupe, W123 means sedan ("Wagen") and S123 means estate/station wagon of the 123 Series. 300 means 3.0 lt engine, D means diesel, E after three numerals meant fuel injection and E before three numerals means E-class (Executive?) There used to be only two series of cars, now there are many.

The N/A diesels used only one fan belt to drive the alternator and water pump, while the turbodiesels used two belts.

Hope this helps.

So you think the belt I have broken is the water pump/alternator belt? If thats the case, whats the best place to buy it? I know Bimmer guys have pelicanparts.com and bavauto.com. Does mercedes have similar sites that are gonna be cheaper than the stealership? I think it's this because the car wont start. And I imagine the car would still start without the aircon, and without the power steering working.

Also, with the trunk, I just need it open this one time since, through a series of dumb events, my dads truck got a flat, and he had to put the flat in the trunk of the mercedes, so we need to open the trunk to get the wheel for the truck out. After that, it's not so much a big deal, just an inconvenience.

So I guess now the obvious question for me is other than glow plugs and vacuum pumps, is this just another straight 6 engine, just like a gasoline based engine? If so, my confidence just shot through the roof.

I'm guessing brake servo means booster, in which I can see how all of that stuff works by vacuum. This might be a dumb question, but could I find the main hose, if there is one, and use a shop vac to possibly open the trunk by creating the vacuum effect that way?

As for the series question, I guess bmw is loads easier to understand, but I'm sure I'll catch on soon enough.

Your help has been great, and I appreciate it!
 

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One of the attachments shows the belt configuration. Two for the alt/water pump. Buy in pairs.

Auto Parts at AutohausAZ - OEM Auto Parts - Discount Replacement Parts, Resources and Car Care Tips or

Discount Auto Parts Online - Import Auto Parts -- PartsGeek.com among other sites. Pelican parts too.

Yes, you can start the engine without the AC or PS.

It's a straight five cylinder, otherwise, as you describe.

If you have the master key, use that to open the trunk. Often these systems develop leaks, so you can't introduce vacuum to open, or you'd be able to by unlocking the drivers door lock. If you don't have a master key, the dealer is your best bet, take proof of ownership.

The main vac line is that large one going to the brake booster. Use a measuring device of some kind on each of the orifices to determine your pump condition, 21+ inHg near sea level is normal. You may have closer to 15 inHg going to the VCV, that's normal too.

If you have a North American car, no headlight dipping option. PC has good info.

You'll have to elaborate on the non start issue, but with one belt on the alt, it'll spin the water pump, so that won't stop you from starting, even without any belts, it would start, just overheat.

And welcome aboard, ask away.
 

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Discussion Starter #5
One of the attachments shows the belt configuration. Two for the alt/water pump. Buy in pairs.

Auto Parts at AutohausAZ - OEM Auto Parts - Discount Replacement Parts, Resources and Car Care Tips or

Discount Auto Parts Online - Import Auto Parts -- PartsGeek.com among other sites. Pelican parts too.

Yes, you can start the engine without the AC or PS.

It's a straight five cylinder, otherwise, as you describe.

If you have the master key, use that to open the trunk. Often these systems develop leaks, so you can't introduce vacuum to open, or you'd be able to by unlocking the drivers door lock. If you don't have a master key, the dealer is your best bet, take proof of ownership.

The main vac line is that large one going to the brake booster. Use a measuring device of some kind on each of the orifices to determine your pump condition, 21+ inHg near sea level is normal. You may have closer to 15 inHg going to the VCV, that's normal too.

If you have a North American car, no headlight dipping option. PC has good info.

You'll have to elaborate on the non start issue, but with one belt on the alt, it'll spin the water pump, so that won't stop you from starting, even without any belts, it would start, just overheat.

And welcome aboard, ask away.
Excellent, thanks. I just talked to my dad, because I am trying to diagnose this car without ever having tried to start it, and I am going off a text picture he sent me, so thats what I'm going on. He says now it wanted to start, sounded like it was trying to, and then he got click click click. I'm gonna go with a dead battery, and the belt broke also. So Now I'm chasing a dead battery and belts, so I apologize for wasting you guy's time on a non-issue.

Is there a particular reason I should buy the belts in pairs? I am on my phone right now, so I will check those diagrams when I get home, thanks for posting them.

He does have the master key, he describes them as one being square at the top, and one being oval. I'm not sure, but thats the description I got.

Just for quickness sake, will the booster in the back with the master cylinder, or will it be somewhere else?

Thanks for the clarification on the cylinder number, I noticed it was a straight configuration, so I took a stab at the number being 6, since that seems to be a common number.
 

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The alt needs two belts, so get 'em at the same time (same manufacturer), that's all.

Yes, the square head is the master key.

The master cylinder is bolted to the booster, can't miss it.
 

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Discussion Starter #7
The alt needs two belts, so get 'em at the same time (same manufacturer), that's all.

Yes, the square head is the master key.

The master cylinder is bolted to the booster, can't miss it.
Alright, thanks. I got my first look at the car today, and the second alternator belt is slack, so I guess I'm going to need both anyway. Thanks for all your help!
 
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