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Saving a 92 500sel

11K views 128 replies 18 participants last post by  Daniel R 
#1 ·
I found this car and want to save it! The only thing I can find wrong with it is the standard engine wiring issues. I have always loved this style Mercedes, and am glad there are others whom share my opinion of them. I purchased this one incredibly cheaply. I know that is usually a bad sign, but I know the original owner (who I bought it from) and he always maintains everything. I hope to repair the harnesses and enjoy this nice ride.
All this being said, where can I get the harness from affordably? Am I better off rebuilding it myself? ( I am a master mechanic, but have mainly repaired american cars, and some classic british) What should I watch for other than wiring, and the cooling "T-Pipe"?
thanks
Dan:)
 

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#2 ·
Welcome aboard! I'd check ebay for the harnesses as well as Mafiadon's thread. He's doing a similar job with a 500. Flush the tranny fluid, oil, coolant, plugs, coils, rotors, caps, check when the timing chain was done last mileage wise, replace the thermostat and radiator, check all the suspension/subframe bushings, etc. If you've worked on older cars you know what to look for/what to do. The more questions you ask the better we can help you! Once you get it back up to showroom condition, you'll find these cars are very reliable and fairly easy on the pocketbook. It's getting them back to that point that takes the huge toll and defeats so many people. How many miles are on the car? Post up some more pictures when you get a chance.

Cheers,
Ricky
 
#3 ·
Am I better off rebuilding it myself?
if you can, it will always be cheaper. As a master that should be no problem for you.

congrats to the car

an

Flush the tranny fluid, oil, coolant, plugs, coils, rotors, caps, check when the timing chain was done last mileage wise, replace the thermostat and radiator, check all the suspension/subframe bushings, etc. If you've worked on older cars you know what to look for/what to do.
Jup... I think nothing to add. . Maybe an A/C check.
 
#5 ·
The car has 116000 m on it. has charcoal interior. I have to ask about tranny but I know maintenance has been by the book, if not better. I really like this car, more comfortable than my couch. cooler looking than any luxury car. and more horses than my El Camino. I will post more pics soon.
Anyone know where to get the wiring crimp on ends, so I don't have to solder onto the old ones?
thanks
Dan
 
#6 ·
These beast's are known to get over 500 miles on a full tank with mix city and highway driving. I currently also have a 1992 500sel dark pearl grey color all one color.I mean i have to say that these are the last true benzes EVER made, specifically the 1992-1994 W140 500's. No offense to anyone else, just my 2 cent$.
 
#8 ·
Hey Daniel, IS your cluster odometer digital? and also do you have a glass or metal moon/sun roof? I'm asking because i have a digital odometer and a glass sunroof whare as a majority of other w140 owners 92-94 have the opposite. Im thinking because i have a Canadian model.
 
#12 ·
Wow! That is a really beautiful find!!!

Welcome comrade :)

Looks really neat from the pics, probably not too much work to do if u lucky.

One main thing you must ensure if u want to rebuild the wire harness.. Use HEAT RESISTENT wire! Try keep the same gauge as the original. And you will have to rebuild the entire harness..

Since you have the expertise with soldering and mechanics, you have nothing to lose by tring to rebuild it. So go ahead! BUT, first read the DIY write up about rebuilding the harness. Another member did a great tutorial with pics.. After seeing that, get the materials together. Set aside a weekend and a few 6 packs of beers and you good to go lol!

How long has the car been sitting?

Also, post up your VIN here on this thread so we can get u get u the Data Card for your car, very useful document..

Best of luck, don't forget to keep us updated..
 
#14 ·
I might be wrong but I don't think the 92's had digital odo? The only thing that looks dig on my 93 is the OT !!

Btw: One nice looking ride! Good luck on your rehab! When my friend and I go to our tues nite car auction I have been watching a 140 sitting out behind a gas station store? I have to stop and find out the story on this car! My luck the guy is a hoarder and wont't sell or wants a million dollars for it!!



Smokie
 
#16 ·
I hope to repair the harnesses and enjoy this nice ride.
All this being said, where can I get the harness from affordably? Am I better off rebuilding it myself? ( I am a master mechanic, but have mainly repaired american cars, and some classic british)
thanks
Dan:)
Nice car, Dan - and welcome to the W140 club

Rebuild it yourself. Buy a copy of the WIS/EPC from flea-bay and if you can't find a copy of Star Finder (wiring diagrams and electrical) then PM me - I'll burn a copy and mail it to you.

For rebuilding the loom, invest in a Dremel. You'll find it easier and you'll likely lose fewer fingers than if you try to cut the plugs apart with a craft knife. The PITA is the connectors of course.

Just document, label and photo everything as you go. The top loom will most likely be worse than the bottom one.

Dave
 
#17 ·
Metal sunroof was standard, the digital odo tells us it was replaced.

MB had a batch of analog odo's that failed early in the use of the car, and when they failed, the dealerships replaced them with digital ones.

REgarding the wiring harnesses, do not attempt repair of the harnesses (there are two; engine and body) as you cannot get them fixed properly due to the connectors. PHoto of failed body harness (for a 600SEL), below:
 

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#18 ·
My harness doesn't look nearly that good!! I can barely identify colors. Most of the insulation fell on the ground like rice crispys. If I could find the oem wire terminations I would be inclined to rebuild the harness. If not I will have to buy a factory built one. If anyone has one please let me know. I will post my harness number in this thread later tonight.
and thanks for all of the info so far!!!
Dan
 
#19 ·
No. No!

To replace the body harness in the photos, takes about 8-hours. That's after about 5-hours to remove the old one! You cannot risk an unhappy ending with this job. If you miss one connector, leave one part of the wire itself exposed, if you do anything but a 'factory finished job', you will have wasted that time and effort installing a problem you will never be able to solve without resorting to doing the process all over again.

I don't care how good you may be as a tech, but get a new harness. Your time alone is worth it! Throw the old one away!

A faulty wiring harness can do more than cause headaches - you could blow your engine! Ask me how that's possible if you don't already know!
 
#21 ·
If you find out who he is, please let us know. I have one to rebuild on a nice 1993 500SE that came my way for a ridiculously low price too. I'm happy to rebuild the loom if I have to. I'm a licensed Radio Ham and I build a lot of my own equipment, so I'm not afraid of such things ..... it's just that someone could save me a *lot* of time....

Dave
 
#24 ·
I completely disagree with Stryker..

Those wire harnesses he showed in the pics seem like its ALL the engine bay wires.. The only ones that you will have to rebuild is the Top engine wire harness, and as a precaution as do the bottom wire harness..

Also the ETA wire harness is worth a look..

But the main one that is most likely causing all the engine problems the Upper / top main engine wire harness.

This connects on the right hand side of the vehicle, runs as a single loom then spits up into two looms, plugs into each fuel injector, the MAF, two ground wires, camshaft sensor, engine heat sensor, and about 4 other connectors. Its not such a huge job removing its as Stryker may suggest. Those job times he mentioned are dealership quote times, and thats for an S600..

You my friend have an S500. Much easier to work on that an S600.

So I say if you feel confident enough with a soldering iron and no stranger to auto electronics, just go ahead and rebuild yours. Insulation colours dont matter as long as the connection points is kept the same..

Removing the wire harness will take less than two hours. Replacing it will take slightly less time. The most tricky part about the whole is the metal clips that secure the harness plug onto the fuel injectors..

Rebuilding it may take from 5 and up to 10 hours depending on your workmanship.

Just make sure what ever materials you use, are high heat resistant, minimum 200 degrees Celsius..

Its your choice at the end of the day comrade..
 
#27 · (Edited)
I completely disagree with Stryker..
Disagreeing with Stryker is redundant and unnecessary.

I don't believe there has ever been a failure of the body mounted harness on a 500. A 500 will have three harness weaknesses - upper engine, lower engine and ETA. ETA is not a separate harness but with the part, and quite easily rebuilt.

The upper harness can be purchased for $528 + shipping (under $10, ask for a quote) at parts.com, the only place that anyone should ever consider buying an expensive Mercedes dealer part. It goes in in about 2 hours for the average DIYer, less for many.

Rebuilding a 119 motor harness is not that difficult and if you do it well not at all dangerous. Actually it's not dangerous even if you don't do it well - as evidenced by the condition of the old harnesses.

A lower harness is even easier to rebuild. Failure of the lower harness has no meaningful impact beyond the oil pressure and level gauges. It has the starter and alternator wires but they are not prone to failure.
 
#38 ·
If you take your time and invest in something like a Dremel to cut the connectors apart (and some good heat-reisitant polyester resin glue to stick-em back together again then One Man And His Soldering Iron can rebuild these looms. The 500 is less scary than the 600! But you can do both. It's just a bunch of wires. Unlike setting up a Holley 4-barrel there's no voodoo involved.:)
 
#26 ·
then in that case you see its not such a horrendous job as others may want you to believe lol..

Just go ahead and rebuild it comrade. Just measure 4 times each way lol, even without all the diagrams, you can do it yourself just by replacing one wire at a time. Before you know it, you holding a completely rebuilt engine wire harness :) At that point you give yourself a pat on the back for saving thousands of $$$$ lol
 
#30 ·
so I took the harness off again, (put it back on to keep bugs from building nests in the connector ends.) Am going to post pics of how bad it is. Checking around to see if any of my old dealership buddies are still around. If not, I am going to the nationals next week to check out some custom harness builders.(and to see the cool cars)
Dan
 
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