Mercedes-Benz Forum banner

SEC Pro's and Cons

4K views 42 replies 21 participants last post by  xlimodriver 
#1 ·
I have a 99 R129 which I absolutely love to drive. Alas it is not practical for all things and a little more room would be nice. I do all my own work so having another Mercedes is not daunting although I am not into "pulling" engines anymore. So I have been looking at SEC's for my daily driver. Mostly at my 89-90. My question though is what should I look out for when lookin? Typically I look for California or Southwestern cars due to no rust but are there things to stay away from? For instance on the R129 the top hydraulics must function or it gets expensive to repair. Same with the cars with wiring from 94-95 wiring harnesses. Last what would driving an SEC be like compared to the R 129? Thanks in advance
 
#3 · (Edited)
its old school cool
make sure the owner has all of the records.
W126s are well built and easy to maintain.
to my knowledge, they are no known design flaws or issues with the w126.
the only issue know is time- these cars are over 25 years old, things will fail or break
 
#4 ·
Agree, the ASR was not "perfected" on the W126, and as a Late W124 owner, not sure it was there either but it is not a problem on mine. Anyway, same stuff applies - avoid car with prestone II running thru it. Expect to replace 28 year old rubber with MB as it is pretty cheap from MB with free shipping relative to the after market. Timing chain, tensioner and guides must be changed as it is the M117 Achilles heal. Rocker arm wear due to cam oiler issues should be inspected, and since the cam cover is off as well best to replace the cam oiler kit on both sides of the engine bay.

SLS system is simple, only the rear wheels but it is quite neglected, so fluid at a minimum but at some point spheres, struts and reseal of SLS pump will be needed as they leak. Finally, the M117 begins to weep oil from the back of the head area, so this may be an issue in the 160-200 mile range to replace head gasket. Several while you are there tasks as well like all the manifold rubber parts you cannot see are petrified and leaking air.
 
#5 · (Edited)
All the W126s have a problem, the rubber parts, including the o-rings. After 25 years, all the rubber bits are hard and don't do their primary function. Vacuum connections leak, fuel lines front and back are prone to cracking and leaking, valve seals don't. The o-rings are problematic for the transmission, SLS pump, power steering pump, AC compressor. I had my trans rebuilt, but *all* the rest are DIY, especially with advice from the experts here.

That said, these are marvelous cars!! Once I got my rubber bits taken care of, these are great daily drivers. I cleaned and polished my 560SEC and now take it to the nearby Sunday morning cars & coffee.

Haven't driven an R129, but you can do a lot to an SEC. Stock, with 15" rims, stock shocks and springs, they're boulevard cruisers or, as Road & Track said back in the '80s when they tested one, this is a world class GT car. On my SEL, I cut one coil off the front springs to get the Euro ride height and put on 235/45/17 rubber. It is just a bit stiffer than stock but will go around a corner rather well. My SEC has H&R lowering springs, new standard (comfort) shocks, thinner spring pads, 245/40/18 rubber on it, and a positraction differential. That car will fly!!

Whaddya want?? :)
 

Attachments

#6 ·
This SEC I have is the best "used car" I've ever owned. The PO (or his Daddy) had a boatload of work done to it before selling it to me including rebuilt heads with new timing chain and bits, rebuilt tranny, H&R springs, and those wheels (ack ack). I've improved and upgraded a little with a few front end parts, Euro bumpers, and better looking wheels. This example rides and drives like a new car now. You can't go wrong with one of these
 

Attachments

#7 ·
You'll probably find the ride a bit wooden compared to the R129. But otherwise good to drive, relaxing, huge boot. (Trunk?) Even the rear seats fit people in surprisingly well.

MPG isn't so good but since it was excellent for the era, it could be worse for now.

Pushbutton climate control isn't reliable like the semi automatic version is.

Great build quality and generally very fixable.
 
#14 ·
Biggest benefit is they only have two doors so they are cool looking, not old man looking. If you are concerned with fuel mileage you should look elsewhere. Hyundais and Yugos get good mileage. So do Pacers and various other shit cans.
It all depends on what side of the fence you happen to be standing on

I don't worry so much about fuel mileage but the last trip we made to Memphis, almost all interstate, we got 22 MPG. That's not too bad considering it's a big car AND has a V8 under the bonnet AND will quickly get out of it's own way when needed without any effort
 
#13 ·
Agree 100% if you care about miles per gallon you're in the wrong brand. Who the hell thinks "how many miles am I getting to a full tank" for god sake things can't be that bad right. I mean you want to drive what you always wanted and you finally have it; the last thing on my mind would be fuel mileage. If I want it I don't mind paying for it.
Rant over.
 
#15 ·
Definitely agree about the "younger man's" Benz aspect - I sometimes feel a little self-conscious driving the "old man's car" SEL, and I almost never think about those things. The SEC can be mildly sporty with some upgrades and even looks the part to some degree. That said, no W126 would be considered a truly youthful car by the typical observer. In terms of power, it depends on your expectations. The 560s will move, they're no slouch even compared to most newer cars, but if you're wanting the same sportiness as a 500SL you'll probably have to keep looking.

Anyway, with regard to the "what to look for" question, the biggest single thing is neglect. The difference in price between a well-maintained, mechanically perfect car and one that looks good but needs attention isn't nearly as much as it probably should be. That's not to say you should walk away at the slightest issue, but deferred maintenance is expensive and time-consuming to correct. So know what you're getting before you commit. Really, about the only "hidden" problem you might find is rust underneath the back glass, even on an otherwise rust-free car. The rest is pretty easy to find with a lift and some poking and prodding.
 
#17 ·
Oh, and in terms of mileage, I've hit 20 MPG several times in the SEC and pretty close in the SEL. That's highway driving in the summer (actually, even driving in Seattle traffic last year didn't drop it by much); admittedly, it can get pretty bad in cold weather and short trips. I'm pretty sure you could easily average over 20 on the highway with careful driving, but that defeats the purpose. I don't think it's a fuel hog at all for what it is, but what it is is certainly not an economy car.
 
#18 ·
MT Merc, I would sure like to know your secret to getting 20mpg! I consistently get 17mpg on the highway almost no matter what. Just finished an 800 mile trip at mostly 80mph and above and didn't even get 16 but that's unusual.

I will have owned the car seven years this March and have kept gas and mileage records from the beginning. The overall average is 14mpg. I'm not complaining, it's the price of admission and I'm happy to pay it. But what is your secret for getting 20mpg??
 
#23 ·
Thanks! I hope I don't come across as defensive with such a long post. I just thought I'd go into detail as to some reasons my car seems to do better than the reported average and the EPA figures - no issues with your question at all. I also wanted to be clear that I don't typically get 20 MPG, in case I seemed to be implying that. Really, it was kind of cool to actually look at the numbers and to see the over 2 MPG improvement the head work (presumably) gave me.

Talking about it also makes me wonder what kind of mileage an SEC could get with a more modern/optimized transmission setup, either manual or automatic with lockup torque converter. Another one of those "when I'm a rich man" projects! :D
 
#25 ·
MT quoted, "In addition to premium fuel and moderate driving, I'd say the things that help me are lighter weight, synthetic fluids, upgraded exhaust, and a fairly solid engine. Between the euro bumpers, air pump removal, and lighter exhaust, I've dropped at least 100 lbs (and never felt better!). I run Mobil 1 15W-50 in the engine and Royal Purple 75W-90 in the diff; both full synthetic. The exhaust is AMG clone tri-y headers and 2-1/4" pipes, which flows much better than stock and improves exhaust scavenging. Hard to tell how much, but I think that makes a difference.

On the engine itself, I would venture that the best mileage comes from engines with a significant amount of miles on them. That's because the internal friction keeps dropping even after the initial break-in, and it takes a long time for these engines to reach the optimal wear point (well over 100,000 miles, I'd say)."

Yeah, I forgot a couple of points, PO had the heads rebuilt 50K ago, car now has 227K total, air pump and bracket deleted, Euro log exhaust with true dual pipes, Euro bumpers, and don't know if it matters but PO installed H&Rs lowering the car (I'd think it would help with not as much wind under the car)
 
#28 ·
Yeah, I forgot a couple of points, PO had the heads rebuilt 50K ago, car now has 227K total, air pump and bracket deleted, Euro log exhaust with true dual pipes, Euro bumpers, and don't know if it matters but PO installed H&Rs lowering the car (I'd think it would help with not as much wind under the car)
Your SEC has even more in common with mine than I realized, pretty similar mileage (mine's at 242K) and H&R springs. If yours is Arctic White, it's even the same color!

1783pictures said:
The big con for me is I'm driving it too much! Any excuse to drive it instead of my Malibu. That's a problem. I need to stop LOL!
That's understandable, and the solution is clear: sell the Malibu to pay for gas to drive the SEC! :D
 
#29 ·
Yup, Arctic White and Palomino (only they call it something else, cafe or something :dunno: )

I mix up the driving betwixt me coupe and me S10 truck. ANY road trips or trips to the Doc I take the coupe unless I'm gonna have to haul something bigger than a suitcase. Have I mentioned I just LOVE driving me car
 
#32 ·
It's the only car I ever use to visit the neighborhood animals.:wink:wink

:eek :eek :eek Do my eyes deceive me ?? :eek :eek :eek you take that fine machine down a (gulp) DIRT ROAD ??

I have self imposed myself to NEVER take mine down anything but asphalt or concrete, the truck is for "off roading" (and that ain't often)
 
  • Like
Reactions: mramay
#38 ·
DAYUMMMMM (emphasis on MMmmmm :grin) secret garden. It's been a while since . . . . . . can't any more til I get a scrip. Around here we have choppers looking for it, a former co-worker is doing 2 years because of a "flyover", they were waiting for him when he got home from work that day
 
#39 ·
Wooky, just to set the record straight, my comments above were just strictly fiction. I buy my weed just just like everyone else in town, from the creepy dude who hangs around the skateboard park.
That's not even a photo of me, but I do admit that I sported the same hair style back in 1969.:wink
 
  • Like
Reactions: wooky_chew_bacca
#40 ·
I was paying attention to those "big as yer arm" monster buds :eek Years ago (before the "flyovers") a friend had a few down by a creek in the "forest", buds literally as big as your arm and 5-6 feet long. I don't partake any more, too risky in a "non recreational State"
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top