So I’ve been sorting out my new to me c280 the last three months. I had a good success experience fixing a pesky steering wheel vibration. Apparently these cars have a lot of different things that can cause vibes but here is what I did to solve it.

New tires with balancing. This helped but didn’t completely fix it.

DIY home alignment. I used my Fast Trax alignment gauge to set the toe at 1mm toe in. This helped a lot. The prior owner must have hit something and knocked it out. It was like 12mm toe out when I bought the car.

The last bit of shaking was ironed out by changing the idler arm bushing and the drag link/tie rod assembly. I had a helper shake the wheels while I looked around under the car. There was quite a bit of ply. I originally thought it was worn wheel bearings given how bad the wheel shake was but I packed those and adjusted them and it didn’t help. So I pulled the tie rods and idler arm bushing and replaced them with URO.

Before you jump all over me for putting URO on the car I didn’t want to spend too much. The car only cost me $2000 and I am not too sure how long I’ll drive it. And I have found the quality of URO has been going up in recent years. Nonetheless I am taking a risk but it is pretty small considering how inexpensive the parts were. Also the new parts were new and beat my 150,000 mile parts by a wide margin. Anything was better than the rattling clapped out originals.

And the vibes are gone. I had a nasty one between 35-40 mph. Also I had this speed related hum that has also gone away. I’m pretty happy.

I’ve fixed a number of other things on the car like door locks, keys, oil, trans fluid, corroded coil contacts, vacuum leaks, ignition lock mechanism, evap hoses, serpentine belt and fan clutch. It was a pretty neglected car. Cosmetically it looked good but the prior owner was more of a spit and shine guy and not a mechanic.

The car is finally shaping up and becoming a fun driver.

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79 300TD “Old Smokey” AKA “The Mistake” (SOLD)
82 240D stick shift 335k miles (SOLD)
82 300SD 300k miles
85 300D Turbodiesel 170k miles
97 C280 147k miles

We need a pic.

Niiiiiiiice...all those items that are "not that bad" add up to a lot. Enjoy the new ride!

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"Rudeness is a weak man's imitation of strength" - Eric Hoffer

Right after I posted this my radiator exploded. The tank cracked along the mold part line. I put in a new radiator and while I was in there I noticed a few things. The car runs well and the temps stay between 80-100c.

My fans don’t seem to turn on. I searched around online and most people describe a system with two relays - blue and green that get messed up and the fans don’t go in fast or slow mode. The problem is my car is a late 97 and it seems to have a lot of 98 stuff on board. Particularly it doesn’t have the aux fan relays. I’m not sure how the car controls the fans but it seems to be done with a digital component (motronic?) somewhere.

Not sure where to start. I tried to take the connector off what looked to be the coolant temp sensor and it snapped in half. I gently put it back together and the car still runs without throwing codes and the gauge works. Not sure if this car uses two sensors one to do the engine control and one to do the aux fans. It does seem to have two. They’re pretty inexpensive so I’ll order both.

This one:

https://www.pelicanparts.com/More_Info/0115425117.htm?pn=011-542-51-17-M85&bc=c&SVSVSI=2615

And this one:

https://www.pelicanparts.com/More_Info/005153232864.htm?pn=005-153-23-28-64-M253&bc=c&SVSVSI=2615

Not sure which is which but they appear to be measuring coolant temp. Might as well swap since one is cracked and the other maybe old.

Another interesting thing I found is the sound deadening material in the trans tunnel collapsed down and was rubbing on the front flex disk. It made a buzzing sound as I drove around kind of like when we used to put cards in the spokes of our bicycles as kids to make motorcycle noise. It took a long time for me to figure out where the buzzing was coming from. It sound like it was a bad speedometer cable in the dash but this car has an all electronic speedo. The good news is I found the offending dynamat an cut it away from the driveshaft. The car no longer buzzes.

So things are really coming together. I think my AC will work better if my fans come on when I turn on AC. Right now they don’t and that isn’t right. It still gets cold but I think all flow is from the viscous fan clutch pulling air through.

While under the car I found I was missing a shift bushing. WOW there is no room down there to install one. The arm doesn’t come off. The press tool won’t fit in between the trans and tunnel. I managed to work it in with hemostats and a screwdriver. Luckily it is softer than the w123 style.

I’ll try to get some photos up of my shenanigans later. The car is nothing to look at. Just another champagne gold Benz with faded clearcoat. I think I have sunk about 40 hours of work into it by now with all my little jobs. It cost me $2000 and it is basically totaled by labor. I have about $1500 in parts invested. This includes tires and the new radiator which were bigger items. Perhaps I overpaid.

Well, I guess we don’t do this for the money. It’s the fun of getting things working again.

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79 300TD “Old Smokey” AKA “The Mistake” (SOLD)
82 240D stick shift 335k miles (SOLD)
82 300SD 300k miles
85 300D Turbodiesel 170k miles
97 C280 147k miles

Some photos:

Cracked radiator. Possibly the original.



Took me three hours to get the radiator out. The m104 setup doesn’t give much space to work. Removing the fan clutch, removing hoses etc took a lot of fiddling around.



New radiator. A- Premium brand. Doesn’t have the metal tube inserts like oem. But I figure if I get five years of use out of this car I’ll be happy.



Bought a URO drag link and tie rod assembly. Quality looked fine. Fit was perfect. Time will tell if it is durable. Price was right. I noticed one of the boots on the drag link mount wasn’t installed correctly. Easily corrected. I got to check the grease and it had a sufficient amount in there. Good



Also tried a URO idler arm bushing. Price was also right. Quality looked good. The original was very loose. This was a big improvement towards tightening up the steering.

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79 300TD “Old Smokey” AKA “The Mistake” (SOLD)
82 240D stick shift 335k miles (SOLD)
82 300SD 300k miles
85 300D Turbodiesel 170k miles
97 C280 147k miles

Good news. I managed to trigger my auxiliary fans by holding down the auto and recirculate buttons simultaneously for 10 seconds. I can cancel the fans by holding the buttons down another ten seconds. This says most of my auxiliary fan hardware is working.

I am just wondering why when I drive around in hot bumper to bumper traffic the fans don’t come on. Maybe I’m not hitting some criteria like appropriate Freon pressure?

I was ready to Hotwire the fans and build my own controller with some mosfets and an arduino to handle PWM. My car has some kind of intermediate MY 1997 update where they went to a pulse width circuit instead of the resistor and blue/green relay system. Somewhere in my car, likely under the dash or in the false firewall there is a PWM speed controller for the fans. They went away from this system a couple of years later. The W210 had it too for a short time.

Well now I know I can just hit the buttons and manually start the fans when I’m in traffic so that’s cool. Literally cool.

I do wonder why my car doesn’t turn the fans on when my coolant temps go into the high 90s or when I activate the AC. Something may be broken in the CCU. Or maybe it is doing what it supposed to be doing and I don’t know how it is supposed to work.

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79 300TD “Old Smokey” AKA “The Mistake” (SOLD)
82 240D stick shift 335k miles (SOLD)
82 300SD 300k miles
85 300D Turbodiesel 170k miles
97 C280 147k miles

Haven’t quite figured out the fan thing yet. AC is cold so maybe the thing is programmed to come on only when the temps get really hot. The fan does come on when I manually trigger it from the PBU. So all the circuitry is there.

I was driving yesterday to get some gas and the vibes are so minimal now I’m able to feel a last subtle vibration that hits at about 2100 rpm in all gears. It seems to go away above that. I figure this is collapsed engine mounts. I will order a set and install them. Hopefully it won’t be too hard. I’ve checked the shop manual and it says just raise the engine remove the mounts so I don’t think it is that hard. But a lot of stuff is really packed in on this car. It has me missing my 123 and 126 in terms of ease of maintenance.

I can only think the design philosophy changed and the computerized cad tools allowed them to pack things in tighter configurations. You can barely reach the fasteners. I’ve had to bend a lot of special tools with my torch and cut down shorty wrenches. I find myself stacking u joints and wobble extensions on my sockets.

In terms of replacement parts I started thinking it was for the most part wear items that I replaced in my 123/6 cars. Ball joints, engine mounts, tie rod ends, vacuum actuators, bad solder joints, steering damper, bushings. This is all the same stuff that an old MB needs swapped out. It’s just harder to get to. Also the online community of people doing things and posting them up is just so much smaller than the diesel crowd. I guess your typical 1997 C280 buyer isn’t your 1982 300D buyer. Most posts online are about taking the car in and having the dealer shoot the parts cannon at the problems.

Anyhow it is coming together. It is super smooth. Hopefully the engine mounts will iron out the last wrinkle in the vibes.

Yesterday I noticed the Balljoint in the upper control arm was squeaky. I split it and greased it. It wasn’t worn enough to replace. It was just a bit dry. Saved a few dollars on that one. Also the control arm bolt on top is a pain to get to. Airbox, radiator reservoir and fuse box need to be removed to make room. Apparently the V6 is even worse for access. Luckily I have the m104 variant. It gets worse mpg but it seems to be a more robust engine on the average.

I must say the C class handles really well compared to my 300D and 300SD. It reminds me more like my uncle’s w124 back in 1987. It is really planted in the turns.

I’ll keep adding to this thread as things come up. They inevitably will. It’s a thirty year old car. Reminds me that my 123/6 cars have needed a steady flow of maintenance on mostly the same parts over the last decade. These are great cars as long as they are maintained properly. It’s interesting how we get them cheap from owners who don’t want to skink any more money into fixing them. My cars have all been totalled by repair work by the time I get them. I put in sweat equity and I can get some of the feeling back of when they were new wonderful cars.

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79 300TD “Old Smokey” AKA “The Mistake” (SOLD)
82 240D stick shift 335k miles (SOLD)
82 300SD 300k miles
85 300D Turbodiesel 170k miles
97 C280 147k miles

Progress!

That last remaining vibe turned out to be motor mounts. I pulled the mounts today and they were 1cm shorter than new ones. Completely collapsed.

I pulled the transmission mount and it was torn. There’s no way of seeing inside it till you pull it from the car. The internal web was completely broken. This was likely my vibration at 2100 rpm.

The car is super quiet and smooth now. A lot of the gear whine is gone. And the vibrations and rattles it would excite elsewhere in the car are now absent. We went for a test ride today and my wife fell asleep. It’s that quiet now.

Unbelievable. The modern (or modern to me at least) Mercedes is amazing when restored with new mounts, drag link, tie rod ends, idler bushing, greased ball joints, new tires and alignment. I’m really happy with this car.

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79 300TD “Old Smokey” AKA “The Mistake” (SOLD)
82 240D stick shift 335k miles (SOLD)
82 300SD 300k miles
85 300D Turbodiesel 170k miles
97 C280 147k miles

That’s great that you’re enjoying getting this car back up to snuff. It’s a fun story too

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97 e300d, 78 300Dt, 95 E300d, 94 E320 estate

The car is just amazing now. I haven’t done much since the last post. It is super smooth and really fun to drive compared to my diesels. Handles like it’s on rails. When I acquired the car it was really loose in the steering and wandered all over the road. A lot of steering shake too. I knew it was wrong because Mercedes would never produce a car that drove that poorly. After all the repairs it handles like a Benz.

Sometimes it gushed hot air out the vents unexpectedly when the ac was on. It was a sticking duo valve. Common issue. I cleaned it off and it’s great now.

I had some issues with my vacuum door lock retrofit but that was my own engineering so I needed to refine the routing of the actuator bar a little. It works well now. That’s about it. The car is a driver now.

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79 300TD “Old Smokey” AKA “The Mistake” (SOLD)
82 240D stick shift 335k miles (SOLD)
82 300SD 300k miles
85 300D Turbodiesel 170k miles
97 C280 147k miles

Darn I spoke too soon and jinxed it up. The car threw a p0341 code. Cam sensor signal out of range. I just ordered a sensor. Hope that fixes it.

__________________
79 300TD “Old Smokey” AKA “The Mistake” (SOLD)
82 240D stick shift 335k miles (SOLD)
82 300SD 300k miles
85 300D Turbodiesel 170k miles
97 C280 147k miles