Topic: My Custom 1980 300SD Project Part 2

[ptashek]

I painted five wheel covers so I have a spare. Painting them was a first for me, but they came out acceptably.

I think you should give your self more credit - that's a nice looking paint job
Good practice run for re-spraying your car, or would you not risk going this far?

[Squiggle Dog]

I think you should give your self more credit - that's a nice looking paint job
Good practice run for re-spraying your car, or would you not risk going this far?

Thanks. Before I paint my car, I have to remove all the dents and dings. So, I have to learn bodywork and take the time to get it totally straight. When it comes to painting, I might as well have it done professionally, because otherwise I'd have to rent equipment, a place to do the painting, possibly mess it up... It's probably wiser to have someone who knows what they are doing spray the paint. But, I'd strip down the car and have it down to bare metal if need be if that will save substantial cost. I'd try to buy high-quality paint for the job and would color sand it after it was sprayed to remove any orange peel.

[Squiggle Dog]

I am likely going to be leaving the Mercedes scene. My financial situation is dire due to a sleeping disorder which makes it difficult to work, and I have a lot of time-consuming self-improvement I want to do, anyway. It's getting way too difficult to maintain and restore a W116 and all these rubber, vinyl, and plastic parts just don't last in the Arizona heat. My 300SD is in extremely good mechanical condition, so now is a good time to sell before something breaks that I can't afford to fix.

My 1967 Universal fintail station wagon was going to be restored into a daily driver, but it's a huge welding project and completely unrealistic. I bought it several years ago and had hopes that by now that I'd have a decent income and able to restore it, but I was delusional. It's also getting increasingly difficult to get any parts for these old cars and there are just so many expensive rubber and vinyl parts to replace.

I also have thousands of dollars in debt that I can't pay off any other way. If I can sell these vehicles and get out of debt, it would be a huge relief. My roommate has cars I can use if I need to drive somewhere. If I do purchase another vehicle, it will be something simple and utilitarian like a Willys Jeep station wagon powered by some kind of diesel powerplant.

I will likely have both of my vehicles listed on eBay in the near future. They are great cars for someone with a decent income, but that's not me. I have to be realistic and make some changes in my life.

[rumb]

what model is your Universal?

Sorry to see you go, I have enjoyed reading your journey from Seattle to AZ. quite amusing.

good luck in the future.  PM me some more info on your Universal.

[JasonP]

Squiggle, I think I speak for many of us when I say we could not have done it without you. Your generosity and knowledge and awesome write-ups have given us so much help. I purchased my first Mercedes when I was broke and unemployed and carless, against all "good" advice from others: they are old, they are too expensive to fix, etc. But that $1k car got me to work for five years, and I live in the country. If it were not for this W116 forum and people like you, I never would have been able to do it.

Do you still have the car bug, or are you just done? My 300SD is still sitting in my yard, with all my tools and parts and books and manuals in the house. I got a VW Passat a few years ago and have not even so much as performed an oil change since. It's just nice to have someone else do it now. I got mine through a car rental agency - they sell their cars off, they have something similar to a Certified Pre-Owned program. It has not given me any troubles whatsoever. I have a sentimental feel for the Mercedes, but I think the car is wiser than me and is saying "Move on dude, I'm done. Look at me. Really? I served my purpose, now go and find yours." My car thinks she's smart or something.

[Squiggle Dog]

Rumb, I sent you a PM.

JasonP, thanks for the kind words. I'm not really that much of a car person, but I'm incredibly unhappy with the cars that are made these days and just don't understand why new cars can't be as good-looking and simple as the old ones. But, by owning a vintage car as a daily driver, I've been forced to teach myself to repair it and spend a lot of time immersed in the car culture to facilitate keeping it on the road.

Because I have to do all my own repairs, others often have me work on their cars for them. It gets overwhelming at times and I would love it if I never had to work on a car again. I really want to be an artist and musician, but find myself spending all my time repairing either my, or others' cars. 

Right now I think the wisest thing for me to do is get as much as I can for the cars I have and pay off my debts. Start fresh. When I get another car, it will be something old like the Willys wagon I mentioned, something that's only bare essentials and doesn't have so many parts that it makes it hard to maintain and restore (or get price-gouged by things like window and door seals).

[ptashek]

I second what JasonP said. Can't really add much to that.

If it weren't for the cost of shipping to Europe, I'd be first in line to buy your 300SD.
To me that car is a legend and should stay within the org.

I wish you all the best.

[avantbenz]

Damn, SquiggleDog - that's a shame to hear. You're such a big part of the community.

What instrument(s) do you play?

[Squiggle Dog]

Avantbenz, I play guitar, bass guitar, keyboard, violin, and mandolin. Or, at least I used to, but haven't really played in years and it's really depressing because now I feel like I can't even read the notes on the page, let alone remember them on the instruments.

I ordered some compressor fittings as the ones I had ordered years ago didn't seem to be angled correctly. I ordered a #8 45 degree and a #10 180 degree, both without service ports because there isn't enough room at the back of the compressor for that to be a suitable location. I ordered a couple service ports that I will put inline with the hoses. I also ordered several feet of #8 and #10 barrier hose I so I can make my own hoses and will then have them crimped at a shop.

I started trying to remove the center console. It's a difficult task, anyway, but it seemed really stuck even though I thought I had all of the screws removed. I also removed the front seatbelt guides but it was still not budging. The plastic braces of the console were already broken and the parts were never able to be attached to it securely, and it started to rip. Finally, in frustration, I tore the console to shreds. It turns out there were two screws still holding in the console at the rear. Oh, well. I felt really upset about destroying the center console as it's not like you can just buy spare interior parts for these cars. Good luck finding a used brown center console (and brown dashes in good condition are completely impossible to find).


I do have a spare brown console that I removed from a car I parted out. The plastic braces are in good condition, but the vinyl is cracked all over. It will have to do. I ended up destroying the corner of the dashboard when I was pulling it out. I really despise W116 interiors. I also gave the glovebox door a few punches because it kept popping open when I was trying to loosen the zip ties for the wires that were attached along the bottom of the dashboard.

I look at the automatic climate control and can't believe anyone would make something so complicated.


I removed the heater box. I'm going to do what I can to simplify the system. I pulled out the manual system I have and it turns out the heater box is cracked and broken. Rabbits chewed up much of the wire harness and cables. Even the manual system seems overly complicated with vacuum controls all over. I might end up ditching the Mercedes climate control entirely and make something using universal controls and wiring.

[Squiggle Dog]

I was hoping that I could simply use some of the wires on the original harness, or could at least tap into them. But, the wire harnesses between manual and automatic climate control are vastly different. The manual system is overall wired directly to the fuse box, while the automatic system uses many smaller gauge wires that go between several different locations. So, I decided the only way to do it probably is to replace one wire at a time.

I spent hours carefully cutting off the wrapping on the wire harness so that each individual wire is accessible. I then started removing the wires that aren't needed. I removed the power window and power sunroof wires since I converted them to manually operated ones for increased reliability. The less wiring I have in the car, the better.




After I have all necessary wires installed and accounted for, all the extra wiring will be removed so it's not complicating things. When that's done, I'll re-wrap the wires with new cloth tape. I'm trying to undo a lot of the over-engineering so the car is more reliable, practical, and simple to repair. There were so many zip ties and getting any access to where the wire harness goes through the firewall was SO difficult. It's fortunate that the two 8mm nuts at the bottom of the fuse box and wire harness support were already loose, because they were almost inaccessible. I had to use a very small ratchet for one, and a flatblade screwdriver with a socket on the end for the other.

[Squiggle Dog]

I removed most of the automatic climate control parts. It was satisfying.


I have most of the wires for the manual system installed as well.


Even though the wire harnesses are very different between automatic and manual, there are a few wires that are routed the same and are even the same colors, however, the manual system calls for wire gauges about twice the size that the automatic system uses (the manual system uses a few heavy gauge wires that are wired directly while the automatic system uses many light gauge wires that jump all over the place). I replaced the light gauge wires with the heavier ones so I don't burn down my car. In areas like around the conditioning relay where space was tight, I was able to tie the new wires to the old ones after I cut an end off and was able to pull them through the harness tubing. In the picture below, the ws/sw colored automatic climate control wire is a 1,5mm². The one used in the manual climate control is a ws/sw 2,5mm²; nearly twice as thick.


To make things more challenging, the wiring diagrams in the factory service manual are not entirely correct. For example, the 1979/80 116.120 300SD USA diagram shows a vt color 4mm² wire going from the alternator junction block to the #1 terminal on the air conditioning relay. However, in both my car and a spare 1979 300SD wire harness I have, the 4mm² vt wire goes from the alternator junction block to the neutral safety switch. No wire actually connects to the #1 terminal of the air conditioning relay. However, on the wire harness I have from a 1974? 450SE that had manual climate control, it had a 2,5mm² vt wire going from the alternator junction block to the #1 position of the air conditioning relay, and then a smaller wire connecting from it to an ignition relay (which the diesels don't have). I am guessing the large purple wire was not necessary on the diesel cars and must have been done away with after the diagram was written.

This is really a lot of work and very technical. It would be very easy to get something wrong. I do not recommend this to the average person. I don't think many people in the world would be motivated enough to see it through, anyway. If I were to do the work for someone, I think I'd have to charge thousands of dollars to be worth the labor. These complicated climate control systems are certainly a curse for these cars and one of the main reasons they get junked.

One problem I have is that the wire harness from the manual climate control car was cut at where the wires from the blower switch connect to the blower motor resistor plug. I'm hoping they are long enough that I can solder on new ends, but I might have to splice wires on the ends so they'll reach (which I'm not happy about as I wanted to do this without any splicing, and all wiring being 100% correct including the colors).

[Squiggle Dog]

I've been wracking my brain over all the changes I'm having to make in the wire harness, but I'm pretty close to being done making those changes. Sadly, I'm going to have to splice several wires because ALL of the wires in the donor harness going from the blower motor dial switch to the blower motor were cut at the firewall (I still don't understand why I did this years ago when I was extracting the harness from the donor car). Fortunately, the wires at the blower motor resistor plug on my car are the same colors and size and are just long enough to reach them (in the ACCII system, these wires connect from the blower motor resistor plug to the servo, so they are very short).

It won't really matter because they will work fine and not be seen since they will be wrapped with new cloth tape, but I'm the type of person that likes to do things 100% perfectly and it would have only taken a couple extra minutes to pull the wires through the firewall instead of cutting them while saving me time and effort when installing them in my car. I must have thought they wouldn't be needed when I pulled the harness from the donor car six years ago (yet when I have sold manual climate control systems to people, I managed to keep this part of the harness intact).

Speaking of this, a grey 1979 W116 300SD with a red interior was on eBay a few months ago. I sold the previous owner the manual climate control and red interior which he actually seems to have been successful in installing, and it appears he left the car's wire harness intact, unplugged unused wire connectors, and added the ones he needed--while my approach is remove the wrapping, remove unneeded wiring, add needed wiring, and then wrap it all back up. He also painted the car himself and installed Euro bumpers. Whoever bought that car got a real gem.

I installed a 16" auxiliary fan from a second generation W126 and read that I need to upgrade the wire harness to handle the higher amperage of the fan, but the W126 uses the exact same wire size (2,5mm²) and colors (black and brown) as the W116, so it's not necessary to rewire the fan. However, I want to wire the auxiliary fan so it comes on with the compressor instead of the pressure switch, for improved air conditioning performance. ROLLGUY sells a plug-and-play wire harness with relay that will accomplish this--and after thinking about it, I think I understand exactly how it works (power from the wire going to the compressor attaches to a connector in the harness and travels to the relay in the harness, which lets power flow from where it's connected at the glow plug relay, through a 20 amp inline fuse, down to where it plugs into the compressor, powering the compressor, while power also flows from the harness and connects to the auxiliary fan, where it powers it [and the auxiliary fan plug on the body is not used] while the ground wires at the auxiliary fan and compressor wiring connect to the harness and then travel back to the relay location where it grounds to the body with a screw.).

However, I also want the auxiliary fan to come on with the coolant temperature switch on the engine so it will lower coolant temperatures if the engine runs too hot. I'm trying to figure out that one so I don't lose this function by getting the auxiliary fan to run with the compressor. If I run the wire from the coolant temperature switch to the auxiliary fan, it will cause the compressor to kick on (which I don't want) unless I run that wire to the relay in such a way that it will only activate the auxiliary fan...

I've been reading through air conditioning threads (many of which have diminished effectiveness due to Photobucket images not showing up) and was considering replacing the expansion valve (TXV) with an orifice tube (OT) and adding an accumulator (to keep liquid refrigerant from reaching the compressor). However, by the time I was done reading the threads, I think that I'd be best off retaining the expansion valve because they seem to be safer and more effective. Adding an accumulator may be beneficial as it would help protect the compressor from liquid refrigerant reaching it, and it may increase performance (some W126s have accumulators).  However, it would be another part for which I would need to find space, it would frustrate the hose routing I have planned, and it may not be needed in an expansion valve system. Right now adding an accumulator is a "maybe" but I'd rather not add one if it's not going to be of any real benefit.

I think that I will use refrigerant R-12. Even though more R-12 has to be used than R-134a when charging a system, R-12 seems to perform better. R-12 seems to still be available for purchase, one way or another. I live in Arizona and imagine it's probably easier to get it here due to the hot climate and close proximity to Mexico where R-12 is still being produced. I had considered hydrocarbon refrigerants like Duracool and Freeze-12, as I had read that they were both superior to R-12 and they are easy to purchase. However, I think that this is pure marketing and while they may work as well as R-12 for a while, it seems they have a short longevity due to different particle sizes. They are also flammable. I was under the impression that R-12 was also flammable, but apparently it's not. This video hits close to home; it's in Phoenix and toward the end a W116 that was using a hydrocarbon refrigerant blew up: https://www.youtube.com/watch?v=ANtAbkKrOuI&feature=related .

R-12 seems to be the best option and is even better for the environment than R-134a. I had considered using R-134a since I wanted to "get with the times" and use a "more environmentally-friendly refrigerant" and would be servicing the ENTIRE system anyway with parts compatible with and suited for use with R-134a. With a parallel-flow condenser, larger auxiliary fan, and Sanden compressor, I'd probably have as good or better than stock air conditioning running R-134a. However, I'd have even better performance using R-12, so why not go with that? I want the best possible air conditioning in my car since I live in an extremely hot climate (120F summers and 100F+ most of the year) and have the opportunity and ability to alter anything necessary to increase the performance.

Since access at the compressor is limited, I am going to add inline service ports to the high and low-pressure hoses. The ones I ordered have R-134a fittings on them. This may be a problem when it comes time to charging with R-12. I imagine there is a way around this, but I looked for inline service ports with R-12 fittings, and it seems no one sells them? I did see some inline ports that are for switches, and it almost looks like maybe those could be used for R-12 fittings. Hmmm...

I would, however, like to see if there is a compressor oil which is compatible with all refrigerant types in case laws and availability change years later and I'm forced to use R-134a or something else, and won't have to flush the system of the old oil to change refrigerant types.

[Squiggle Dog]

I spent several hours yesterday pondering over how to power on the auxiliary fan whenever the compressor is running, as well as when the coolant reaches 100C/212F, and I think I've figured out a way to make it work using the original auxiliary fan relay, which is:

In early manual W116 climate control systems, the compressor clutch is powered on directly by a blue and green 2,5mm² wire coming from the temperature dial switch (no switches of any kind were used between the temperature dial switch and compressor; pressure switches were not yet in use). A blue 1mm² wire is connected to this wire at the temperature dial switch and connected to the RPM stabilization relay which would raise the idle in gasoline-powered models so that whenever the compressor clutch was engaged, the engine's idle speed would be raised to counteract the extra load.

To power the auxiliary fan whenever the compressor clutch is powered:

1. The existing red 2,5mm² wire at fuse #2 (which has only one wire, as its sole purpose on a W116 is to power the auxiliary fan) connects to terminal 30 of the auxiliary fan relay, providing it with a power source.

2. The extra blue 1mm² wire coming from the temperature dial switch of the manual climate control which would have gone to the RPM stabilization relay on a gasoline-powered model will now connect to terminal 86 of the auxiliary fan relay, which will switch on the relay whenever the temperature dial switch is turned on AND the ETR switch does not disable it.

3. A brown 0,75mm² ground wire at terminal 85 of the auxiliary fan relay will complete the circuit which will make switching on of this relay possible by a signal from the blue 1mm² wire coming from the temperature dial switch.

4. When the auxiliary fan relay is switched on by power from the temperature dial switch, it will allow power from fuse #2 to travel through the auxiliary fan relay and out of terminal 87 where it will travel through the existing black 2,5mm² wire toward the auxiliary fan.

5. The wires which went from the auxiliary fan relay to the refrigerant temperature switch on the receiver drier will be removed along with the temperature switch itself. The wires which went from the auxiliary fan relay to the coolant temperature switch on the thermostat housing will also be removed.

Doing the above should power on the auxiliary fan whenever the compressor clutch is engaged, however, I will be using the pressure switch on the drier, which will disengage the compressor clutch whenever refrigerant pressures are too high. However, the auxiliary fan's power wire will be connected before the pressure switch, therefore the auxiliary fan will remain running and reducing refrigerant pressures even when the pressure switch causes the compressor clutch to disengage.

To power the auxiliary fan whenever the engine's coolant temperature reaches 100C/212F:

1. An added-on 2,5mm² or 4mm² wire (possibly black in color) will be added to fuse terminal #2 (of which sole purpose was to provide power to the auxiliary fan through the auxiliary fan relay). This wire will then go to the coolant temperature switch on the thermostat housing which switches on when coolant temperatures reach 100C/212F and then switches back off once the coolant lowers down to 95C/203F.

However, the original coolant temperature switch (part number 006 545 14 24, red color, M4X1.5X1 threads, on at 100C/212F, off at 95C/203F) is a single-pin unit which grounds to the engine through the thermostat housing and is not suited for what I need.


I found that there is a coolant temperature switch (part number 006 545 15 24, red color, M4X1.5X1 threads, on at 100C/212F, off at 95C/203F) which has two pins and grounds from the second pin after going through the wires which complete the circuit.


2. Another 2,5mm² or 4mm² wire will go from the second pin of this 2-pin coolant temperature switch replacement and will run back through the firewall and will connect to the black 2,5mm² wire which powers the auxiliary fan (inside the firewall before it reaches the loom after the firewall so the part of the auxiliary fan wire harness in the engine compartment will be left untouched).

One thing I wonder about: Can the coolant temperature switch handle the full load of the auxiliary fan running through it? The original design is for it to switch on a relay, which then draws power from the fuse box to power the auxiliary fan, so there is very little current running through the coolant temperature switch and even small 0,75mm² wires are used. However, what I want to do is run the full load of the auxiliary fan through it (and of course using much larger wires). I just hope the switch can handle that much current.

3. If the coolant temperature reaches 100C/212F, the coolant temperature switch on the thermostat housing will switch on and allow power from fuse #2 to flow through it and toward the auxiliary fan, thus powering it. When coolant temperatures drop to 95C/203F, the coolant temperature switch will shut off and thereby shut off the auxiliary fan.

By doing the above, the auxiliary fan will always be powered by fuse #2, which is solely used for powering on of the auxiliary fan. A 16 amp fuse is stock, however, I have the freedom to install a larger fuse if necessary because of the higher amperage of the upgraded 16" second generation W126 auxiliary fan and since there is nothing else being powered by fuse #2.

Increasing the size of the wires in the auxiliary fan wire harness is not necessary because even the second generation W126 uses the same size 2,5mm² black and brown wires. However, because the added wires which will run between fuse #2, the coolant temperature switch, and the auxiliary fan power wire will be rather long as the coolant temperature switch is located on the opposite side of the engine compartment than the auxiliary fan wire harness, I may use larger 4mm² wires to and from the coolant temperature switch in order to keep down the wire resistance.

If the auxiliary fan is being powered by the coolant temperature switch, it cannot flow back and inadvertently power the compressor when the air conditioning is not on because the auxiliary fan relay which is switched on only by the power wire coming from the temperature dial switch will be switched off.

When the air conditioning is switched on and the auxiliary fan is running with it, if then the coolant temperature switch engages, though there will be two powered circuits colliding, because both of their power sources is from fuse #2, there should be no consequences except possible decreased wire resistance as the fan would be powered by two wires instead of one. If the coolant temperature switch shuts off, the auxiliary fan will stay running until the either the air conditioning is shut off or the ETR valve shuts it off. Or, if the air conditioning is switched off, the auxiliary fan will stay running until the coolant temperature switch shuts off. The power cannot backflow into anything and cause inadvertent powering on or damage.

I still think ROLLGUY's wire harness and relay to power the auxiliary fan whenever the compressor is engaged is brilliant, due to it being plug-and-play, easy to install, and easily removed if desired. As long as a person doesn't wish for the auxiliary fan to come on with increased coolant temperatures, that's the way to go. And so far I have not ever observed increased coolant temperatures in my car--even in stop-and-go long commutes in 120F Phoenix traffic--with the exception of when I was going up the steep grade at The Grapevine in California at 70 MPH while returning from Washington with my car fully loaded inside and out.



So, most people probably don't need the function of the auxiliary fan coming on with increased coolant temperatures anyway, and what I'm planning to do requires drastic measures which is beyond the scope of many people--even most mechanics aren't going to spend hours/days figuring this stuff out. But, I'm already so deep into it with my manual climate control conversion, so I might as well do as much as I can.

[floyd111]

You know there's a company called U-Haul, not? .
How do you not scratch and dent your car carrying stuff like this?

Just for laughs.. No need to understand any language here.
https://www.youtube.com/watch?v=zPJ8eDv-1N8

(Yearly tradition where many of the immigrants in Holland pack their stuff for their once-a-year return to Turkey or Marocco, carrying insane loads of shit for selling and gifting in their home country)

[Squiggle Dog]

U-Haul is too expensive. Using my car was by far the cheapest way as it gets good fuel economy and I don't have to pay for a rental and mileage (which is important because it was a 3,000 mile round trip). I'm just very careful the way I load things and put moving blankets under everything. My paint is really bad anyway, but if I ever get my car painted, I won't be strapping things to the body anymore.

Funny video. It seems they are using an appropriate vehicle.