1976 W115 240D -the slow restoration

[katja]

I've decided for my own reference sake, and ease of searching, that I would start a thread about my car and what I do (and have done) to restore it, and what comes up in the process. Emergency problems & questions I'll post in the other forums as they come up. First, I'll start with some history.

Around 1976, my dad gave me a Corgi toy W115 240D as shown in the attached photo. It was one of my favourite toy cars & I played with it all the time, though the springs in the rear wheels sagged....something that would come back to haunt me when I bought a real one. But, I digress. One 4th of July, I destroyed the scratched & tired toy 240D with firecrackers.

My uncle had a '69 220 diesel and I remember riding in it, as well as his '79 300SD and euro 280SL. I became a big Mercedes fan as a kid, and I collected ads & literature. In 1981, my parents considered buying a W123 240D and I remember the test drive at the Phil Smart dealership in Seattle. They ended up buying a Peugeot 505 diesel instead.

I learned to drive on the Peugeot, but the car was starting to really fall apart by the time I took my driver's test. If my parents had bought the Mercedes instead, undoubtedly I'd still be driving it.

Later, after a decade of driving my beloved but uninteresting Ford Explorer, I started doing more & more of my own maintenance but wanted a classic, older car to play with and learn how to do repairs. I thought it would be cool to restore an older classic car. I also missed the sound of driving a diesel and I missed driving a standard transmission. One day, I came across a grey '74 240D for sale for $650 in the driveway of a Maaco. Of course - the perfect car for me to play with!

I contacted the seller but he said the day he put it up for sale, it stopped running. He was going to get it fixed & let me have it for $500.

Half a year went by and the car was never repaired. Water leaked in through bad rear window seals & by that time, I didn't want the car. By that time, I had done a lot of reading on this and other forums. Checking craigslist, I found another one for sale that was running and test-driveable, and I bought it for $800, knowing it needed a lot of work. Little did I know how much work it really needed.

[katja]

My first tasks were to replace the rubber piece missing from the front bumper, and properly attach the license plates which were zip-tied on. I then cleaned out the car & found all kinds of treasures and tons of decomposing seat pad horse hair.

All the marker lights were dead, and the interior lights had green & red bulbs. Changed all these and the lights were working - except the dash lights. After messing with the infamous rheostat for months, I just jumpered across it so the darn lights would stay on.

The speedometer cable was disconnected and the gauge glass was all loose, held in place by folded up pieces of paper because the clips had broken off. Some time later I got a cluster from another member here & replaced all the bad parts, including the chrome trim rings. The clock is still dead, though.

I installed an aftermarket CD player & speakers just to fill the holes. The twin 3.5" speakers in the dash happen to be blown.

The seatbelt buzzer would go off randomly while driving. I disconnected that and it has remained that way ever since.

The heater blower and air conditioning doesn't work. I tried to get at the blower to lubricate it, with no success. One doesn't really need it, anyway, except when the car is stationary. As for air conditioning - well, that robs about 5 of the 65 horses under the hood, so I don't think I really want to turn that on anyway.

[katja]

On to the engine. I quickly discovered that oil changes were no fun. After draining the thick molasses out of the engine, I realized that the lack of recent maintenance records probably meant lack of recent maintenance. There were bottles of 10w-40 oil in the trunk that didn't appear to be diesel-rated. The oil filter was missing its pre-filter, which I didn't realize was supposed to be there until some years later.

The air filter had been replaced with some oiled-foam POS. The original was in the trunk, and had spilled black oil everywhere. I made a mess of my friend's parts washer restoring the air cleaner, and had to spend $100 for a new plastic pipe to connect it to the intake.

The oil filter was incredibly hard to change with collapsed engine mounts, and it turned out the transmission mount was bad too. Had an indy mechanic change all those out, and he did a compression test but I never actually got the numbers. Valves were adjusted, fuel filters & fuel lines changed, and the car idled much more quietly. I had to replace the oil pan & valve cover gaskets, the oil cap gasket and breather hose, and later, the fuel tank hoses as everything leaked.

I have been using Mobil 1 synthetic oil, either 5w-40 or 15w-50, though the latter no longer has a "C" rating, so I guess I'm back to the 5w-40, which I wonder if it might be too thin for a worn engine with a lot of blowby.

[katja]

Oh yeah, I forgot that tiny little battery was replaced with a proper one, along with a failing negative battery cable & rusty ground. The starter would frequently not engage, so my friend and I replaced it, from the top; it took two people to get that heavy beast out.

It didn't cure my starting troubles for long. The primer pump failed, and air leaks left me stranded twice. A small leak at the prefilter also caused a no-start one day. I couldn't find it, and had the car towed to my indy, who couldn't find it either until the lines were pressure-tested.

The transmission has no synchros left in 1st & 2nd gear, and changing the transmission fluid to Redline MTL didn't help. I quickly learned to do double clutching & heel-toe downshifts, and the transmission shifts perfectly now

The ride was bad & the rear end sagged badly, so all shocks were replaced with Bilsteins and tires were replaced with new Sumitomos of the proper size from TireRack. The handling has been pretty much restored, though I need new tie rods and the left rear spring sags.

The windshield wiper only worked on the driver's side as the linkage had been disconnected. I struggled trying to fix that for months, but finally contorted myself in the right position to snap the linkage back on (hard when you can't see what you're doing).

The car was originally Astral Silver, but had been poorly repainted and was peeling everywhere. A proper repaint was not affordable for me, so I had Maaco repaint it Zodiac Blue. It turned out pretty well and I get lots of comments on how good it looks. I also added some Hella 500 fogs on the front bumper as I couldn't find the proper fog lights for a reasonable price, and there were already holes in the front bumper. I bought a "Biodiesel" emblem for the trunk from Colorado Biodiesel.

Since that time, I have done just regular maintenance and no further restoration, other than changing the headlights out to Euros just recently. It has been a very reliable car, though there are many parts that are going to need attention and replacement very soon.

[JiveTurkey]

I'm very glad to see another man who has discovered the love of an old Merc. Excellent name you've chosen as well. In russian it would be spelled KatЯ. I really like the colour you've chosen. If you'd like I could paint a spare set of hubcaps I have laying around for you so they'd match.

[suginami]

Originally Posted by JiveTurkey

Excellent name you've chosen as well. In russian it would be spelled KatЯ.

In Japanese it would be spelled カーティヤ.

[katja]

Thanks for the comments and for the offer, Jive. I actually plan to strip the remaining silver paint off the hubcaps and leave them natural chrome. As strange as this sounds, I'd really like to get Bundt wheels or even better, the Bundt-style hubcaps, so I can switch out the look depending on my mood But they are hard to find. The drawback of the Bundt wheels are that they are harder to clean.

Today I cleaned the oil bath air filter....and I took steps to avoid an actual bath in its oil. I used a fluid transfer pump to suck out the old oil, then cleaned the filter & housing in my parts washer and blew everything out with compressed air before refilling the bottom of the housing.

There was quite a bit of oily residue in the intake, but it appears that is coming from the crankcase ventilation tube - no surprise there, as the engine has quite a bit of blowby. There was some oily muck on the "throttle plate" in the intake - can that be cleaned with throttle body cleaner? I wasn't sure, so I left it alone.

[katja]

Noticed my fuel pre-filter was looking dark the other week so I changed it. Lots of gritty (like grains of sand) black bits came out. What is this stuff? Rust from the tank? (there is some rust visible at the filler neck). Decaying pieces of fuel lines? (lines look OK from the outside, but they are 5 years old). The dreaded diesel tank fungus? Or did a stranger pour something in my fuel tank? Never seen this before.

My car does sit usually two weeks at a time without being driven and then only gets used one day, and I do have B20 biodiesel in the tank most of the time. I'm thinking I need to pick up some StarTron and a few more prefilters, and then replace all my fuel supply & return lines. It's been running fine, nice & smooth, no loss of power, but engine starting is not as quick as it should be, hot or cold.

[Govert]

Originally Posted by katja

The oil filter was missing its pre-filter, which I didn't realize was supposed to be there until some years later.

That isn't the pre-filter, but the main filter.

[Govert]

Originally Posted by katja

Noticed my fuel pre-filter was looking dark the other week so I changed it. Lots of gritty (like grains of sand) black bits came out. What is this stuff? Rust from the tank? (there is some rust visible at the filler neck). Decaying pieces of fuel lines? (lines look OK from the outside, but they are 5 years old). The dreaded diesel tank fungus? Or did a stranger pour something in my fuel tank? Never seen this before.

My car does sit usually two weeks at a time without being driven and then only gets used one day, and I do have B20 biodiesel in the tank most of the time. I'm thinking I need to pick up some StarTron and a few more prefilters, and then replace all my fuel supply & return lines. It's been running fine, nice & smooth, no loss of power, but engine starting is not as quick as it should be, hot or cold.

It can be all of the above, and it is also possible that the lift pump sucks oil from the IP and puts it in the fuel line. Since most of the fuel is returned to the tank, oil will get into the tank, causing black dots in the prefilter.

It is not as likely on a W115, because the IP has its own oil supply and isn't linked to the engine oil circuit.

[katja]

Well, a quick summer update. I've been busy with work & haven't been doing anything on the car. I did add some StarTron to the tank and was quite impressed at the result. Good stuff.

I need to get some new injector return lines and then I'll install the new injectors. I'm not sure which one is "bad" but there's definitely one that is sticking. I entered Katja at the Seattle MBCA Show & Shine car show a few weeks ago, and that was a lot of fun...so of course, I did a complete wax & detail (which I have to admit, I like more than doing repair work). She was running so nicely when driving in, that someone even commented that he thought it wasn't a diesel. However, when driving out, that injector started to nail loudly again.

Anyway, I thought I'd share a photo of a REALLY vintage (and beautifully restored) 1937 540K (IIRC) cabriolet that stole the show this year, for all you vintage fans.

[Merce]

1969,Mercedes 220D.4cyl automatic

[katja]

On New Year's Eve I won an auction for a set of Bundt-style hubcaps - for $10. I've always liked the look of the Bundt wheels better than the steel ones, but haven't been able to find a set that were in good condition that were actually affordable.

From an eBay ad, these actually look like Bundt wheels. They are even made in Germany. But, when you put them on the car, they don't look right. If you look closely, you can see many differences between these and real Bundts.

They came also very dirty and scratched, so I cleaned & spray painted them. Some have chips out of them and are warped too.

Well....they're interesting to say the least, but I'm keeping my stock metal hubcaps until I find some nice aluminum wheels.

[mantis176]

What a beautiful car you have, Katja. I love the w115 body style, and hope to own one some day. I have a '79 w123 240d that I've been doing some resto/preventative maintenance. Its funny you mention your parents were considering a Pugeot 505, because mine were as well, but in the end they went with the very 240d I'm working on now.

One of the first things I started to work on a few years ago was the fuel tank (the car sits sometimes). I removed it, treated it with the por-15 fuel tank kit, cleaned the fuel sender, tank screen, new fuel hoses, new pre and main fuel filters (it still had the original 1979 main filter, yikes) and did a diesel purge. I also got into the habit of adding Biobor anti-algae fuel treatment and Redline DFC, and occasionally Lubro-Moly every other fill up. Its amazing how much better it runs when the fuel system isn't clogged anymore!

Although I prefer the body-color wheel covers, your faux bundts look great especially with the fresh coat of metallic paint. These cars really "pop" with a wash, wax job and all of the rubber armor-alled.

[mercmad6.3]

These engines do have a pre filter ,it's a round plastic thing sits up on top the main filter .I have found plenty of these engines with them missing.

I am sure your oil is too thin, and that can cause major problems with the rings glazing the bores ,and this causes blow by. You need a thicker oil in these old engines and seriously,Synthetic or semi synthetic is simply a marketing ploy to separate you from your money.
The normal grade is 10W40 and you must use a detergent oil. It's vital to remove the sludge from the engine which builds up between changes.
The black gritty stuff you describe in your fuel is a bio infection . If you go to this page
Mercedes-Benz Specifications for Operating Fluids: Engine Oil, Gear Oil, ATF, Coolant, Brakefluid
there are several page on the correct oil for your car plus a page on how to remedy the bio infection. See 138.0
I usually carry a spare fuel prefilter in bag in the glovebox. it can be surprising where this stuff appears from but I find gas stations are the worst culprits although most refuse to acknowledge that the diesel problems cars owners suffer from are their fault.
I would suggest you add 1 lter of automatic trans fluid to every 1oo liters of fuel to keep the injectors and valves clean and prevent further infections .
This will also help deglaze the bores and free the rings in the pistons and cut the blow by down.