73 w114 280 questions - PeachParts Mercedes-Benz Forum

wolf_walker · #1 11-09-2008, 02:15 AM

I have an opportunity to obtain a pretty clean 280 with 116K on it, and I have a few random questions and a general request for advice.
I have a good background in w123/126 cars, but this one is a bit earlier.
I had it on a lift today and observed surface rust on the random bolted on metal parts underneath, and some surface only stuff on the floor. I think it was up north for a time early on, then here in NC, and garaged, for most of it's life. The only bad rust is the lower pass rear quarter, it needs to be cut out a few inches up and a repair piece welded in, this does not look like a really big deal.

Mechanically, it seems pretty well off considering. Starts up well cold or hot, runs pretty smooth, not a lot of noise from the head but you can hear the cams and chain in there.
No smoke, etc. Bit of delay going into reverse which I'm used to, seems to shift alright.
Has a few random oil leaks, and a PS leak from somewhere, none of which are bad.
Drivers seat is flat but the cover is good, been there done that.

Mostly I'm curious is there are any un-obvious things to check, anything that commonly bites one in the rear when buying one. I'm also curious, and don't laugh at me, about fuel mileage. I'm assuming 20 on the highway and a bit lower in town? This wouldn't be a daily driver, but it'd be driven pretty often. It seems to be a very solid old car needing a moderate amount of TLC. I haven't seen one around NC this clean and solid in a long time. It's nicer than most of the 123's I see honestly.
Thoughts?

bluebenz · #2 11-09-2008, 08:21 AM

Nice car. I had a 73 280C. Carburetor drove me nuts. Other than that great. Mileage is around 15-17 mpg in town, not more than 20 on highway because engine revs high over 60 mph.

make sure the blower fan works, apparently a tough job to fix.

Mike D · #3 11-09-2008, 08:46 AM

If the Solex 4A1 has never been torn apart then you are good to go. Do not overtighten the top screws on the carb to get rid of any seepage problems. Replace the gasket. The number one killer for the carb is overzealousness on the part of unknowing mechanics. I hate the carb but if properly maintained they'll be fine.

Consider replaceing the transistorized ignition set-up with either a Pertronix or Crane XR700 ignition trigger system.

Double-check the trunk floor. Rust on the passenger quarter is an unusual spot and might be pointing to a more pronounced rust problem. Check the lower passenger rail (where the jackpoints are) thoroughly!

Check under the battery box and along the windscreens lower trim areas for rust.

Don't trust the 116K as the odometers commonly fail and don't record the mileage. It's a simple fix.

Heater fans are a pain and are labor intensive to replace.

A common, dare I say, "normal", spot for oil seepage is at the cam housing to head area. It's a thin metal gasket which gets crushed over time. Re-torque the head bolts and live with it.

The fuel pump can also be an oil leaker but many times all you need to do is re-tighten the mounting bolts.

Pull and clean the strainer in the fuel tank, do a search here on the forum for the procedure.

The rear stabilizer links are probably weak. When they fail you'll hear a "clank" or knocking sound from the rear axle assembly.

Of course, all rubber mountings (engine, sub-frames, differential, transmission, et.) should be inspected. These are normal "wear item" parts and are pretty easily changed. Hey, the car's 35 years old!

I use my '73 280 as my daily driver and it's holding up fine.

I get 14.5 MPG in town and 18-20 MPG on the road with a transmission on it's last legs.

wolf_walker · #4 11-09-2008, 11:16 PM

Had a chance to drive it pretty briefly this evening. Shop had replaced a front brake caliper that had sprung a leak. Couple observations.

It runs pretty well on the road. It feels to me like a points ignition carburated car that needs a tuneup, isn't as smooth as it could be all the time. Nothing terminal though by any stretch.

This transmission..
What put me off old Mercs years ago was the transmission, I'm still not overly fond of them.
This one shifted through the gears without flaring and what I think is appropriately solidly, kickdown worked. Reverse had the customary delay in engaging, 2-3 seconds, not excessive. What I did observe was in reverse, while releasing the brake it sort of shuddered moving slowly, and had a noticeable whine to it. Is this an old age thing with this moder trans? I know my later 123/126 trans did the delay into R thing and would whine some, this one was louder though. The solidity of the upshifts, though they were a little early in my opinion, makes me think it's solid enough, and is likely overdue fluid and strainer. Thoughts?
And while on the subject, how much grief is a manual trans swap, and how rare are they?

Otherwise it felt good, drove well, no odd clunks that I heard in a brief drive. Felt like a w123 with a huge steering wheel and a tad more body roll. And a worn out drives seat, which is no surprise. The odometer works, I could believe the miles but it don't really matter either way. It was running cool on the gauge, 150 or so maybe, it's getting a t-stat tomorrow. The carb needs tuning or a rebuild, I'm no stranger to carbs though it's been awhile, fast idle wasn't coming off, cruise was lean feeling, but it wasn't too bad.

Seriously considering, will sleep on it a few days.

meltedpanda · #5 11-10-2008, 07:43 PM

as mentioned the carb can be a bear if it has been fooled with. The reverse whine could be concerning, if a flair is present. Also as mentioned a pretty primitive ACC make sure switch over valve works and fans ( both if it has AC) work.
That is low mileage, is the asking price reasonable?

wolf_walker · #6 11-10-2008, 11:46 PM

No flare was evident, if the trans dies I'll look into a manual swap for sure.

The asking price, is complicated. It's no out of pocket money, and being rid of a car I'm not really in love with and am tired of spending money on.

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