Topic: My Custom 1980 300SD Project Part 2

[Squiggle Dog]

Since the firewall grommet for the low pressure air conditioning hose (116-997-24-81) is no longer available, I was forced to find a suitable replacement. Part number (113-997-01-81) replaced it as it fits the same size hole and has a similar angle. The center hole needed to be opened up for the hose to fit, so I covered it with electrical tape to protect the surface of the grommet and ground the hole larger with a rotary tool, cutoff disc, and sanding drum. It worked!

The grommet on the far left is a new 113-997-01-81 grommet. The grommet in the center is a new grommet with the hole cut larger so it can replace the original 116-997-24-81 grommet on the right.


The new grommet and bumpers (116-466-08-82) installed on the new low pressure air conditioning hose.


The main reason I purchased the Sanden conversion kit from Klima Design Works was because I was having frustration figuring out the hose routing and they seemed to have a solution for this as their kit came with hoses (however their site does not show pictures of the actual hoses, or the kits installed in any cars for that matter, which would be helpful as it's hard to understand how things are supposed to work).

The discharge hose going from the compressor to the condenser was cleverly designed and fit well. It goes underneath the compressor and has a strain relief bracket. Unfortunately, the low pressure hose gave me problems. With the compressor properly positioned, one of the oil cooler lines was in the way of where the fitting and hose needed to go. To get around this, I reversed the position of the hose clamp so it leaned away from the oil cooler line (which isn't the way the picture in the instructions shows). This allowed for proper clearance, but then the angle of the fitting was wrong so the hose clamp was in a twisted state. The service port would also hit either the strain relief bracket, the oil cooler pipe, the power steering return hose, or the body of the car unless it was positioned exactly as shown, which is different than what the instructions showed, and I doubt if there would be enough clearance to get the charging hose on there.


The low pressure hose seemed like it was about two feet too long, so I contacted Klima. They said that the hose is supposed to loop forward and fit in the bracket on the inner fender as the original did. The illustration in the W116 appendix just shows it going straight back to the evaporator, so a different illustration or instructions would have been helpful. I tried routing it as original, but it seemed to put way too much strain on the compressor fitting, which was at nearly a perpendicular angle to the hose, the hose seemed like it was kinking, and it would have been under way too much tension. I said that I didn't feel comfortable with this, and they said that I could shorten the hose if I liked and they'd send a new fitting to crimp on at no cost; but I'm just going to make my own hoses, which is a shame because that was the whole point of buying the Klima kit.

[Squiggle Dog]

The oil cooler line mounting bracket from Klima didn't fit my car.


The ridge in the center of the power steering pump bracket prevents the oil cooler line bracket from fitting flush.


When I tried tightening down the bracket, the ridge caused it to bend.


I put the Klima bracket up against the bracket from ROLLGUY's kit. I had no problem with ROLLGUY's bracket fitting, and you can see that his is cut deeper to clear the ridge. Klima said it's strange and they have never had any complaints about their brackets before, but if I want to cut mine to fit, they'll let me do it without voiding the warranty. Unfortunately, I can't use ROLLGUY's bracket because it's longer than the Klima bracket as his goes underneath the oil cooler lines and the lower corner sticks out further, so it interferes with the way the hoses on a W116 have to route. The Klima bracket mounts on top of the oil cooler lines, so there is more clearance below, which is another reason why I wanted to try the Klima kit.


I had the same issue with the Klima kit that I had with ROLLGUY's kit; the belt provided (11X950 for ROLLGUY's, 13X965 for Klima's) was way too small to fit. Both claim that it is the proper belt size for the OM617 turbo engines, but the W116 version must have a larger crank pulley as the compressor has the recommended 132mm pulley. Klima suggested removing the adjuster bolts from the bracket and trying to fit the belt. Doing that, I was able to just barely squeeze on the belt, and then getting the bolts back in was tricky. Once the belt was fully tensioned, the adjuster had hardly moved at all. So clearly, that wasn't going to work. I found that for my 1980 W116 300SD, a 13X990 belt fit perfectly on ROLLGUY's bracket, and a 13X980 belt fit perfectly on Klima's bracket.


The 13X990 belt that I was using on ROLLGUY's bracket was a bit too large on Klima's bracket, so I went to AutoZone to try a 13X980 belt since I had purchased the other belt from them being as their Duralast belts were made in the USA by Dayco, which I felt was a better option than a Continental, which are now made in China and I couldn't find that size in a genuine Mercedes belt (and even genuine Volvo in 13x992 are no longer available). Well, this time the Duralast belt said made in China on it. At least the belt fit, so I know the proper size. I figured that if I'm going to run a Chinese belt anyway, I'd prefer to have a Continental. But, then I discovered there is a genuine Mercedes belt in a close size (12.5X975 004-997-36-92), so I ordered one to match the power steering and fan belts.

My overall opinion of Klima Design Works' Sanden conversion kit is that they probably make a great product for the W123 and W126, but it seems the W116 version needs work. I got the impression that I was their first customer to install the W116 kit, but they said that they have sold many of these and have never heard a complaint other than some people didn't like the low pressure hose setup. Their bracket is really well-engineered. Then again, just about all the rest of it didn't fit, and those are the parts that made me decide to try it out. But, for a W123 or W126, their kits are probably great.

ROLLGUY's brackets get the job done and I didn't have fitment issues with his other than the belt alignment being 1/4" off, but some spacers and longer bolts fixed that. The oil cooler line support bracket fit well, it's just that it gets in the way of the W116 low pressure hose routing, but not an issue with the W123 or W126.

Sometimes learning can be expensive, but now I know the pros and cons of both brackets and my car is getting closer to have working air conditioning for the first time since I've owned it.

[Squiggle Dog]

Going back to the plans I had for designing my own hoses, here's my idea for the low pressure hose; a 180 degree fitting points the hose forward as original, and a clamp secures it to the compressor at the strain relief mounting ear.


Then the hose loops backward into the holder bracket on the inner fender, and both the high and low pressure hoses will get inline R-12 service ports in an easily-accessible placement.


When I was removing unneeded wires from the harness, I got carried away and cut the wire going to the manifold overboost pressure sensor and then decided I needed it, as it helps protect the transmission against the high torque from the diesel engine. I soldered the connector back on and replaced the broken sheathing with some from a spare harness.


The connector snaps into a plastic housing which has a cap that screws down over it.


The wire rerouted and attached to the manifold overboost pressure sensor. The sheathing can get stiff due to engine heat and age, but use of a heat gun will soften it so it can be bent to the desired shape.

[Squiggle Dog]

The wire harness coming through the firewall is finished up after some wires were removed and added. The wire going to the manifold overboost pressure sensor was rerouted to go through the sheathing that used to house the wiring for the auxiliary water pump for the automatic climate control.


The grommet on the firewall that used to hold the vacuum lines to the automatic climate control servo got the holes filled with black 1/4" pull-through plugs ordered from McMaster-Carr, and then the ends were trimmed.


The new reciever drier. It's considered a disposable item because it contains a dessicant bag which absorbs moisture from the air conditioning refrigerant, so I couldn't justify spending $212 for one from Mercedes, so I bought a Behr one for $17. At least it looks nice and the sight glass is facing outward so it can be seen, instead of like the one on my car that points toward the radiator.

The two brass switches on it are genuine Mercedes, though. The upper one was about $30, and the lower one was only $23 and free shipping on eBay (MSRP is $82). I had originally ordered a $10 Taiwanese Behr pressure switch, but the prongs were clocked wrong (6 and 12 o'clock positions) and the wire connectors would have had to be bent at severe angles to fit. The genuine Mercedes switch prongs were clocked perfectly at 3 and 9 o'clock. I don't know if this is a quality control issue or just coincidence. I noticed the genuine switch has a small screw in the center, so I wonder if the clocking can be adjusted, but there was no need.


One of the wires that used to power the power windows was soldered to three other wires at the fuse box, so I rolled back the rubber at the ring terminal, cut off the wire, and rolled the rubber back on.


The previous owner must have thought he was an electronics genius as he hacked up a lot of the wire harness to install a sound system which he removed when he sold me the car. Mice also ate a lot of the wiring, so I've had to replace quite a bit of it.

Up next, I need to replace the cigar lighter wires as they were cut off to power the stereo system. They are connected to the wires for the rear dome light switch and relay, so they have to be replaced as a unit. I'm hoping to be at the point where I can start taping the wire harness soon. I have to drive this car to Utah in two weeks!

[Squiggle Dog]

I had to connect a bunch of ground wires together, so I decided to reuse the ring terminal from a spare wire harness since I couldn't find any good ones locally and even online there weren't really any that matched. I can get them from Mercedes, but don't know what size each part number is. It was actually very difficult to get the wires fully removed from the ring terminal because they were crimped and then soldered on. But, with enough persuasion from a MAPP gas torch, I got the old solder burned off so I could open up the terminal.


I inserted the ground wires together into the terminal, crimped them down, and then soldered them like the factory did so it matches the other grounds.


The ground connections behind the instrument panel area were very rusty and needed cleaning. Maybe that explains why the tachometer would cut out occasionally.


Now they are all cleaned up.


I repaired the cigar lighter wiring, replaced the sheathing, and installed the connector cover. I also replaced the left front speaker wires with a spare because they had been chewed up by a mouse several years ago. I'd say that at this point the wire harness is done. Now I've got to tape it up so the wires aren't loose.

[Squiggle Dog]

Recently we've been having a lot of storms in the Phoenix valley area in Arizona, making it humid on top of being over 110 degrees; which has made for brutal heat. One of the storms knocked over a bunch of trees, which damaged the wall.



I converted the power windows to manual a while back, and recently removed the wiring for them, which left spots 15 and 16 open in the fuse box, so I decided I would attach the seat heater wire harnesses there so I wouldn't have to use an auxiliary fuse box. But, I realized that I cut the power wire that went to it, which originally passed from between fuse 1 and 2 to a relay, and then to the spot between fuses 15 and 16, so now those fuses had no power.

I utilized the short jumper wire which was originally designed to go from the fuse box to an auxiliary fuse box and attached it between fuses 1 and 2, and then attached the other end between fuses 15 and 16 so they would get power. I tucked the jumper wire down inside the fuse box after installing it.


Here is the wire harness for the front seat heaters. I had to solder on a new ground ring terminal because I sold the wire harness I had and then later on bought another one, and the person who removed it cut it off.


Here's the front half of the wire harness for the rear seat heaters.

[Squiggle Dog]

The new screen for the new Four Seasons 38604 expansion valve arrived. It keeps debris out of the valve.


I wrapped the wire harness with the first layer of tape, which is 3M Scotch Super 88 Vinyl Electrical Tape. Some parts of it were really tricky, but I started on the outside appendages and wrapped in toward the main body, and then wrapped from the end of the body toward the fuse box going clockwise.


The support braces for the climate control case are installed.


The second layer of tape, which is is 3M Friction Tape, is wrapped over the electrical tape. It looks identical to what Mercedes used so it blends right in and it's hard to tell which parts are original, and which I retaped. Surprisingly, I got all the tape at The Home Depot for about $3 a roll! I ended up using one roll of electrical tape, and five rolls of friction tape. All the tedious installation of the wire harness bracket and relays is finished. Making everything go back together correctly was mentally taxing.


I really had to guess at how to route some of the wires, especially the ones for the seat heaters. I think I got it figured out, and the end is in sight. I set up an appointment on Tuesday to get the system charged with R-12 at a very reputable shop in Tucson which has been doing automotive air conditioning since 1954. So, I have to make sure to at least have the hoses made and installed by then--though that's about the last day I can work on my car because I went to spend Wednesday getting ready for Utah because I leave on Thursday morning.

[Squiggle Dog]

Here is a comparison that puts into perspective just how much more complicated the automatic climate control is compared to the manual type, not to mention all the junk in the engine compartment like the servo and auxiliary water pump:

[Squiggle Dog]

I got a new genuine Mercedes belt (13X975 004-997-36-92) for the compressor. They are usually made by Continental, but this one was made by Optibelt. It's also six years old as it has a date of 7/12. This must be a size that doesn't often sell. At least it's German and has the star logo.


There is a plastic hose holder that goes between the brake booster vacuum line and the high pressure air conditioning hose. I had originally planned to reuse the original high pressure hose, but found rust inside the fitting and didn't want to risk contaminants or leaks, so I made a new hose with #6 reduced barrier, which has a slightly larger outer diameter than the original, so one side of the holder wouldn't fit. I found that I had a spare plastic holder with a larger end on one side, so I heated the plastic with heat gun so it would be more flexible, and pulled both holders in half. Then I swapped the ends so I ended up with one that would fit both the vacuum line and the air conditioning hose.



I used a Dremel rotary tool and a file and modified the Klima Design Works oil cooler line support bracket so it would fit on the power steering pump bracket.


The new Mastercool Hydra-Krimp 71550 hose crimper arrived. It comes with dies for #8, #10, #12, and reduced barrier #6, #8, #10, and #12 hoses. It worked fantastic. I paid $166.43 and free shipping for it.

[Squiggle Dog]

I used copper flare gaskets for the hose connections. There are four sizes used.


New grommets are installed at the firewall. The large hose has a 113-997-01-81 grommet which has had the hole enlarged so it could replace the no longer available 116-997-24-81. I put butyl windshield installation tape around where it meets the hose so it would be water-tight. Even though the new high pressure hose is a little larger than the original, grommet 116-997-03-81 stretched enough to fit.


The Klima Design Works bracket now fits and is installed. I had to drill out the hole on the side to 1/4" so the zip tie would fit. I tried fitting a Mercedes one, but it broke as I think the metal is too thick for an original one to work. I had a lot more clearance for the 180 degree low pressure hose fitting. I ended up removing the rubber from the hose clamp so I didn't have to struggle to mount it to the strain relief bracket on the compressor. I couldn't use the provided metal line holder that secures the oil cooler lines underneath because even when it was tightened up, the oil cooler lines were loose and would rattle, so I used the original from the R4 bracket. Since the new high pressure hose was a little larger than the original, I had to use a bracket from an auxiliary fan to replace the one that mounts to the body.


I made the hoses so that the service ports would be easily accessible and both holes on the support bracket would be utilized (it drove me crazy that it wasn't being used before). I have rubber U-channel which will go between the support bracket and hoses once I make the low pressure hose hole a little larger. The low pressure hose is #10 and the discharge hose is #8 reduced barrier.


The discharge hose routing is a bit tortured. There is a 45 degree fitting at the compressor and the hose bends up toward the support bracket. It gets close to the "cigar" fuel hose, but doesn't rub on it. I used a buffer ring 116-466-12-82 to keep the two air conditioning hoses from rubbing. The larger low pressure hose takes two of part number 116-466-08-82, but I ended up using three to keep the discharge hose from rubbing on it up front. If I had to do it over again, I'd use a 90 degree fitting at the compressor and then put in a 90 degree elbow splicer just after the support bracket. Either way, I feel a lot better about the hoses I made than the ones the Klima Design Works kit came with. The hoses from the kit weren't used because the low pressure hose wasn't a very good design and the oil cooler line support bracket needed modification to fit at all, so I'm not happy with that. The compressor bracket was good, though.

[Squiggle Dog]

I replaced the cheap hardware store grommets that dry rotted for the condenser mounting brackets with genuine Mercedes ones, part number 000-997-31-81. They fit well!


I installed the new receiver drier and found that the threads for the hard line were closer to the drier than the last one, so it was nearly impossible to tighten the nut at the flare fitting. I had to remove all the condenser mounting screws, unbolt the drier, tilt the condenser forward, and use a crows foot wrench on the nut while being careful to not break the headlight glass. If I had to do it over again, I would have fit in a larger condenser, mounted the drier inside the engine compartment, and bored a hole for the upper hose to go through the radiator core support.

I was up until 2:30 AM getting my car ready to drive to Tucson to get the air conditioning charged. I woke up three hours later to drive it the nearly three hours there, which is very difficult for me as I require about 12 hours of sleep a day in order to function. The shop spent about an hour and a half vacuuming the system and charging it with R-12. They came in and said that there was a leak at where the expansion valve connects to the evaporator, so they were going to evacuate the system so I could repair it. After that was done, one of the people in the office said that I had driven a very long way, so they would allow me to repair the leak so they could try again.

I removed the flare gasket and they tried again. It was leaking in the same place, so they had me remove and inspect the expansion valve. The new Chinese Four Seasons expansion valve had deep scratches and pits on the flare surface, so they told me it was junk.


I asked them if they had a 38604 expansion valve, and they said that they had a parts warehouse next door that I could try. I went there and they said that they didn't have a Four Seasons one, but they might have another brand. I said that was fine. They came out with an old stock OEM Edelhof brand made in France, which is what I wanted, but they are $200-$300 whenever I see them for sale. They sold it to me for $50, which was a great deal. It was set up for R-12 and even had the screen filter already inside. The sealing surfaces were also machined to perfection. What a difference between the two brands!


I installed the Edelhof expansion valve and they vacuumed and charged the system again. They told me that it was leaking even worse than before, and that they hate flare fittings because they don't seal well. They let me try again, and I decided that if it didn't seal this time, I'd try to figure out a way to replace the evaporator and expansion valve with an O-ring type, and then I'd have to make new hoses. Upon inspection, I saw that the aluminum flare surface of the new Chinese Four Seasons evaporator (which didn't fit correctly in the case in the first place) had deformed because of the imperfections of the Four Seasons expansion valve and the many times of tightening it. It figures, the two Chinese parts I put on my car were the ones giving me the most trouble. I put a new flare gasket in between and tightened, loosened, and tightened it several times in hopes that it would seat.

It being nearly closing time and having been there all day, the technician came out and said that it wasn't leaking. The total cost was $244.12. On the nearly three hour drive home, it didn't seem that cold and I was worried that the refrigerant was going to leak out. But, the vents weren't installed so I wasn't getting air blowing on me.

I spent the next day trying to recover from the lost sleep and attempted to put the rest of the interior back together so I could drive the car to Utah the next day. I cleaned and secured the fuse box and installed new fuses. I spent hours struggling with putting the dashboard back in. My hands were getting cut up and I was frustrated. It was after 2 AM and I told my roommate (who almost never sleeps) that it wasn't going to happen, so he said I could drive his car.

I slept for about three hours and got up because I had to take the three dogs to the pet hotel and needed to put the air conditioning controls back in so I could drop them off. I got the controls in and wired the CD player and ash tray, so even though the center console wasn't in, at least the dashboard was in and I had all I needed for the trip. So, I dropped off the dogs and started packing.


The air conditioning worked fantastic with the vents in place, even though the recirculating air flap wouldn't stay shut because I didn't have the vacuum lines installed. It got cold enough that I had to turn it down when we got near Flagstaff. My roommate came with and we stopped at Delhi Palace in Flagstaff for a tasty Indian buffet. The car did great on the drive, but I was feeling horrible from the lack of sleep as we got close my parents' farm in Utah. I didn't get to sleep until about 1 AM. I was disappointed to find absolutely no biodiesel stations along the way. Even the Moab Chevron station which had articles written about it offering biodiesel didn't sell it anymore.

[Squiggle Dog]

I found that the air conditioning in my 300SD is even colder than in my mom's new Toyota Corolla! We went through the arts and film festival in Helper, Utah. We stopped in at Udderly Ice Cream, a newly-opened ice cream shop. I ordered a non-dairy raspberry sorbet. My roommate has a little octopus that he brought with him and took many photos with. Here he is in the center, resting on a cone:


We saw the vintage motorcycle museum, which is in progress.


Bands were playing as well:


Me with my mother and stepfather. He's been really good to her.


Me with one of my sisters:

[Squiggle Dog]

There was a car show. No Mercedes, of course!


There was an excellent band called Shuffle playing. They were the best of them all. All of them were top-notch and the guitar player appeared to be the best one can be at it.


Glamour shot of my car on the farm:


My roommate bought a radio/phonograph cabinet at an antique store. It barely wouldn't fit in the trunk, so it went in the back seat.


All of the shirts I've been wearing belonged to my grandfather. He died in 1974, so you know they're old.

[Squiggle Dog]

Driving off.


We had a fantastic meal in Moab on the way home at 98 Center Restaurant, consisting of excellent vegan nachos, phở, a salad, and kimchi.


I was very impressed with my car. Even with the air conditioning running, it got great fuel economy, cruised at high speed (though I was still getting passed by people that insist on driving at least 20 MPH over the speed limit), and I blew past a nice W115 300D by Flagstaff. In the 1,200 mile round trip it didn't use any oil or coolant.

[kjenkins]

    So glad you got your ac working.  All your hard work seems to have paid off.  Also, love the pics from the trip.  Great stuff.