Took a little run down to New Milford Pa. on the weekend to play a little paintball and give the 85 300 TD a workout, other than a wonky cruise control the car ran great and delivered an average of 32.5 mpg, 11.6 km/L for the 600 miles driven. The only thing I wish this car had is an overdrive, driving on I 81 at 65-70 mph had the old diesel running in the 2900 - 3000 rpm range and an overdrive gear would have made me cringe less and possibly delivered even better mileage. So other than wishing for an overdrive and a working cruise control (which is on the list to repair) I think the old Mercedes wagon will make a nice car for long trips .
I guess the turbo doesn't really help. I loved both my 300 cd and 300 td , but I never pulled out into fast moving traffic. I guess if your driving a tank ya gotta sacrifice some speed. Now that I think about the cruise control on both was not a smooth ride
The turbo works great it's the rear gears which if I remember correctly are 3.65-1, they work great in combination with the turbo for acceleration but you run at a higher engine rpm in any gear which is why I wish it had an overdrive transmission for driving at highway speeds, it would keep the engine rpm closer to 2500 instead of the 2900 rpm I currently see on the highway.
Normally when you accelerate in these old Mercedes from a stop when the shifter is in drive the car will start in 2nd and then shift to 3 & 4, but if you floor it from a dead stop the button under the gas pedal is supposed to force the trans into first and upshift from there. It's kind of like driving an old ford with a dual range transmission D2 is 2-3 shift only and D1 is 1,2,3. The 4 speed auto in the Mercedes is nice, I only wish 4th was overdrive instead of direct.
Sounds like it's time for either swapping in a Mercedes trans that has an OD final ratio, or a separate OD unit. I can tell you, your wagon is unhappy at those RPMs. You might also want to try a taller set of tires; it won't cure the problem, but if it knocks a few hundred RPM off its cruise speed, it'll definitely help.
I was gonna start a new thread but I think your on to a good one here Kevin. I too took a weekend trip up to Chester, Illinois. My wife has family up there. We were at here cousins house which was built some time 1800 little farm house. There in the turn around in front of the old barn was this old gas pump. The cousin and I were talking about it and I mentioned I'd never seen one this old and this complete, "maybe on tv" I said. He laughed and said I probably haven't seen one on tv like this because this one is still connected to the tank underground!!!
I wouldn't advertise that fact in a public forum. Illinois is harsh on old underground tanks and it's surprising that this one hasn't been identified yet. Would mean removal accompanied by an expensive hazmat cleanup.
Oops. Yeah he did say something about that. Did I mentioned that it was in New Mexico??? Well it was.... oh well, add that to my earlier pictures of busted nickels that were used on a belt tensioner. Wouldn't be my first encounter with the authorities dang it!!!!
Those are cool pumps especially if they still work. I worked at a gas station while going to college that had an antique pump for kerosene, the owners liked old equipment and kept it certified for use. It always drew attention whenever someone came for kerosene and we dispensed it using the old pump. Figured I should add that I had ordered a new control stalk for the cruise and just installed it so the next time I'm on the highway we'll see what the cruise does.
Please do. Both my 300's did what it sounds like yours is doing in cruise control, real high rpm's and kind of all over the place. This was before I knew the little I know now about cars so I just chalked it up to 78' and 85' technology, and never worried about it
I think he was referring to the Benzo's cruise control; Kevdupuis, check the fuses first. The German-style fuses can hide the strip that burns, so visually inspect them. Then, inspect the speed pickup and the drive for the control motor. If neither yields any obvious problems, the weakest part is the control amp circuit board. I took a Google trip, to find that the solder joints on the circuit card were crap, the capacitors were crap, and foil runs on the circuit card could have minute cracks.
I've already replaced all fuses and made sure the fuse contact points were good and I've replaced the capacitors and reflowed the solder joints in the amp. Replacing the cruise stalk is a 10 minute job (Mercedes made it real easy), if I need to go further I'll dig into the actuator and see if the potentiometer is worn out.
