The "Diseasel" - '86 300SDL - Page 2 - PeachParts Mercedes-Benz Forum

Volvo Diesel · #16 01-11-2017, 11:01 PM

Small world. It would have been too much for me to take on, but I am glad to see it found a home with someone who can keep it going. It sure looked to me like it had been pretty well taken care of for most of its life. I look forward to seeing your continued progress on the car.
-Chris

Diseasel300 · #17 01-12-2017, 03:23 PM

It's definitely not a vehicle for the timid or mechanically declined. Many things that need service/work and for a non-DIY person the cost would be unbelievable. Most of the vehicle is coming back to life with nothing more than TLC, cleaning, and service. Other than some light bulbs and a couple of wiring splices every switch and fixture in the car (except for the seat-belt module [2000], washer pump, and OVP relay[1998]) is what it came from the factory with. Pretty amazing. I've found date stamps of 06/86 and 07/86 on just about everything in the car (built July 1986).

Eventually the car will be pretty sweet. I wanted something rough but with potential that I could fiddle with for a long time and slowly make great. Seems I've found it.

Diseasel300 · #18 01-13-2017, 08:42 PM

Today's task was to rebuild the fuel lift pump. Noticed it smoking pretty heavily the other day, and diagnosed the lift pump as leaking when I found several quarts more oil in the sump than I had added...

OM603 602 601 Lift Pump Re-Seal (O-Rings)

After I change the oil I'll swap out the lift pump and see how we go from there.

Diseasel300 · #19 02-01-2017, 09:04 PM

The latest saga on this car has been correcting the hideously craptastic transmission shifting. Suffice to say, it was an ordeal and a source of MANY faults! You can read all about the back and forth discussion on that topic here:

Lousy Shifting - Where to Start?

The other job that got addressed today was replacing the delivery valve seals on the injection pump. I purposely skipped doing that job when I replaced the injection pump and it came back to bite me. Car would idle on 5 to 5 1/2 cylinders when hot and nailed LOUDLY until RPM's came up above 1400 RPM or so. Even then, it was obvious that it wasn't running smoothly on all 6.

Flash forward to today and the DV's got serviced. They'd been done before in the past, and whoever did the job didn't torque the holders like they should have. I had the torque wrench set to 20Nm and not once did it ever click taking them off.

You can read the back and forth, thoughts, and final conclusion on another thread here:
Delivery valve internal leak as a cause of nailing? Yes? No? Maybe???

In my case, yes, the DV's were the issue. The car now idles on all 6 cylinders and the nailing is a thing of the past. Idle isn't perfectly smooth, but on a car that's had the kind of life this one has, it's pretty good IMHO. Certainly no longer objectionable or shaking the car!

Next task: transmission service!

Diseasel300 · #20 02-09-2017, 11:41 PM

So the transmission service still hasn't happened, I haven't gotten the fluid, K1 accumulator spring, or a free weekend to do the work yet.

So I've been busy doing other things instead. After getting the transmission shifting adjusted, I turned attention to adjusting the boost pressure. As it was, I was making 9-10PSI boost, the original spec is just under 14 PSI according to the FSM. I've seen posts of anywhere from 12-14PSI is considered "normal".

My car has the Garrett turbo on it, and it is not easy to adjust, let me tell ya. I found it easiest to take out the airbox, heat shield, crossover pipe, and EGR riser. Despite my best efforts, there was no way my big hands were getting down in there to adjust the pushrod, so I removed the actuator and adjusted it outside the car. After several adjustments, I finally got it to 13-13.5PSI and I'm happy with it there. You certainly notice when the boost builds now! As a happy side effect, highway and cruising speeds are much easier to maintain with barely any throttle.

Another nice side effect of adjusting the turbo is cooking the carbon out of the head. After the long uphill runs with the pedal on the floor, the engine certainly runs a lot smoother and significantly quieter! With the new DV seals and the extra heat from the highway runs it seems to be doing the engine some good. Will be really nice when I have it fixed up enough to go on a road trip and really cook it out.

This evening I went rattle hunting. Solved the rattling door on the glovebox by adjusting the rubber bumpers to give it a tighter fit. I also adjusted the hinge nuts to straighten it up. Looks a lot better and no more clatter when going over rough spots!

Solved a squeak in the passenger door. The pocket in the door was squeaking where it meets the vinyl backing. A quick shot with WD-40 seems to have shut it right up. The plastic "cup" thing in the door that meets up to the air vent in the dash was also squeaking against the wooden panel in the door. Rubbed some furniture wax on the wood behind it, and that's now silent as well.

The biggest rattle and irritation in the car was coming from the right rear passenger door. Just a CONSTANT creaking/squeaking noise. If the car was in motion, it was making noise and nearly to the point of sending me to the looney bin! It's embarrassing to admit, but that noise was all my fault. When I redid the window regulators, I didn't capture all of the plastic hooks in the door. As a result, the bottom left corner was sticking out and rubbing on the plastic door sill. Took the panel back off and reinstalled it properly and it's quiet as a mouse!

The last thing I did was service the "aspirator" motor for the HVAC system. It's been sounding very unhappy lately. Sadly it's at the end of its life. The brushes are worn down so they're only about 1/8" long and the commutator on the motor has a very deep groove worn in it. I'd imagine it's original to the car, certainly wouldn't surprise me. For the time being, I oiled the bearings, which seems to have quietened it down a fair bit, I don't think it's long for this world though but should still hold me over until I source a new one.

We'll see what gets done next.

Diseasel300 · #21 02-09-2017, 11:44 PM

For anyone wondering, here's a picture of the guts of the "aspirator" motor. It's clearly had a hard life.

Diseasel300 · #22 02-16-2017, 02:53 PM

Well that lasted about a week. Aspirator motor finally died this morning (and BOY what a stink!). Have a new one coming. I didn't expect that poor thing to last much longer, but I was expecting longer than this. Oh well!

In the mean time, every vacuum line under the hood has been replaced. It was truly shocking how brittle some of the original lines were, simply touching them would break in multiple places. A positive side effect of replacing the vac lines is that now the transmission adjustments are even more crisp than they were previously. Some piddling with the Bowden cable, and turning the modulator 1 notch CW has made it a really nicely driving car! 2-3 shift is still a bit crap from time to time, but that's soon to be resolved.

Parts have been ordered to replace the center bearing, flex discs, K1 accumulator spring, shifter bushings, and oil pressure sender. Fingers crossed it'll be ready for a road trip afterwards, everything else is working wonderfully!

Another point of interest is improved fuel economy. The previous tank was ~23.5mpg. I filled up at 1/4 tank left. Currently at the same point on the fuel gauge, and I've done ~100 miles further. It seems servicing the DV's, adjusting the boost pressure, and adjusting the transmission shifting had a profound effect on the overall fuel consumption. When I fill up next, I'll get the actual consumption numbers.

Stretch · #23 02-17-2017, 04:27 AM

Oh wow someone's been busy! Keep at it!

Diseasel300 · #24 02-17-2017, 04:54 PM

I'm sure you can relate, if there's something to fiddle with, I'm gonna fiddle with it! I'm never done working on my cars, a little here and a little there. Goal right now is to get things satisfactory to take it on a 2 hour road trip. Burn some carbon out and give it a good shakedown!

Diseasel300 · #25 02-24-2017, 09:09 PM

So as promised - the fuel numbers. 447 miles on 17.2 gallons of diesel. Comes out to 25.99mpg if my math is right. Not bad for a 31 year old barge!

More small things done recently:

- New oil pressure sender. 1.25bar at idle hot, pegs by the time it gets to 1500 RPM. Nice!

- Oil and filter change. Refilled with Rotella T6 5w-40. Certainly a lot quieter and I swear the turbo spools up faster than with the Delvac 1300 15w-40 that was in there.

- Replacement vanity mirrors! No more people asking "Is there something missing in there?"

- More squeaks and rattles addressed.

- New aspirator motor in the HVAC system. The difference in noise level compared to the original one is nothing short of stunning.

Coming this weekend: New flex discs, new center bearing, transmission oil and filter change

Diseasel300 · #26 02-26-2017, 10:23 PM

Today's work was replacing the flex discs and servicing the transmission.

Flex discs weren't too bad, front one was beginning to crack, but both were ROCK HARD. They felt like they were made of plastic!

Center bearing was in pretty sad shape. The carrier was rotted out completely and the bearing itself was pretty dry.

Transmission service was pretty easy. Drained the fluid out, was still bright red. Changed the filter, pan gasket, and K1 accumulator spring. Spring had fallen apart inside the piston.

New shifter bushings installed as well. No more sloppy shifter and rattling noises!

After cleaning up the transmission and going for a ride, the transmission is definitely shifting a lot better! No more crappy 2-3 and 2-3-4-3-4 shifting!

Unfortunately there's still a driveline vibration. Tracking that down...

jake12tech · #27 02-27-2017, 04:20 PM

[QUOTE=Diseasel300;3686973

Unfortunately there's still a driveline vibration. Tracking that down...[/QUOTE]
Ok, you seem like a mechanically incline chap... But I have to ask cause it's easy to miss, but are you sure you have the driveshaft in the correct position? There's colored marks on the driveshaft that are red and yellow that fade out after the years and if it goes in wrong it will be out of balance and continually vibrate.

Diseasel300 · #28 02-27-2017, 10:00 PM

The DS is aligned correctly. The factory marks were aligned before I took the DS out, and I made my own marks with tape to make sure it went back in the same way I pulled it out.

I have a thread running at Driveline Vibration and starting to lean heavily towards a failing U-joint.

jake12tech · #29 02-28-2017, 08:43 PM

I would bet that it is a failing you joint. And as far as I know they have to be custom made because the dealer never sold replacement you joints. Dumb I know.

Diseasel300 · #30 02-28-2017, 08:51 PM

It does seem silly that they phoned it in on the U-Joint. It isn't like it was new technology or anything, they've been around for centuries. With all the other serviceable parts on these cars, it's nearly causing a brain hemorrhage trying to comprehend the reasoning why the U-joint, which is a part that is typically serviceable, is a throw-away design!