They are excellent solid cars, more tank like than a W124. I can say that as I've had both, don't get me wrong the 124 is an excellent motor and I'd have another but the 140 is a step up, not just in girth.
And the size is the first thing you notice, especially in narrow streets and car parks. But it's all worth it cos they're bloomin marvellous motors.
Things to look for, some of these I've experienced others come from other owners on this forum and the US one:-
Weak springs front and rear, indeed broken springs! - drive a bumpy road if you can and check for squeeks and rattles - the ride should be very smooth and very quiet. These cars are very heavy and the springs take there toll, as do tyres, check them as well.
Uneven wear could just be down to wheel alignment, easily done at a specialist for about £50
Check all the electric kit works esp the Aircon and sunroof. Both could be very expensive to fix, the sunroof in labour costs, the aircon in labour and parts if the evapourator is duff - a weeks work and an interior strip down....very scary. If the aircon doesn't blow cold it could be the evapourator but more likely the condensor, this is the rad at the front of the car and would cost about £250 to put right.
Check the electric seat adjustment and memory works along with the mirrors and steering column adjust, again check the memory function works on these items too, and the mirror fold in.
Check all electric windows go up and down as expected, as you'll know from the 124 the window switches require a light touch only.
Check the soft close feature works on all doors and bootlid, don't be fooled as a dealer tried to pull on me that some cars only had this option on the bootlid - that's crap, if soft close is only working on the boot then somethings wrong with the door closers or the vacuum pump, a £500 part.
While your looking at the doors, they're heavy jobbies, check the door check straps haven't siezed, they'll "click and crack" as you open and close the doors...a cheap fix but they can cause damage to the door and surrounding area if left to their own devices....it happened to mine and proved expensive to fix.
The wipers should be silent when they operate, if they're not replacements are £65 each from the dealer....the rivets wear out on the metal frames and they slop around making a noise....like everything else.....they're BIG.
All 140's I've seen have leaky rear diffs, I keep mine topped up at every service, to be fair it's not that bad.
I don't want to put you off because if you get a good one, these cars make you feel a million dollars.....get a wrong 'un and they could cost you a million.
I always keep in mind the fact that I may have bought a big luxury car for peanuts but running the thing still costs "big luxury car" money. The 500 is an excellent engine, the power is something else....for such a huge car it really takes off like a scaulded cat....it's surprised and embarrased a few "performance" cars before now.
That lot should keep you busy!
, change up and change down. I went to see a car that wouldn't actually drive off the forecourt, in every other respect it was a good car but it would not get out of first gear...the ECU or MAF had gone....I threw the keys back at the salesman for wasting my time.
