Newbie with a few questions. 300SD - PeachParts Mercedes-Benz Forum

ascalise · #1 10-19-2004, 03:17 AM

I just bought an 81 Ivory 300SD for $1700 that has a few minor problems some that I can live with and some that I cant. The car has a perfect body and perfect original paint that still shines. A/C and all electronics work except for the c.c. and tach (intermittent) So far i'm amazed with the car and how well it is made for something so old.

I just replaced the B2 piston and K1 spring kit tonight in about 1.5 hours. I was surprised at how simple that job was. The car goes into the forward gears perfectly now. However, a couple of things changed. When the car upshifts from 3-4 its a little slower and smoother than before. Also, when I downshift from 4-3 it is an INSTANT downshift and is rather hard. Why did this change? Can it be adjusted? I would also like to soften my 1-2 shift as it chirps the tires 9 out of 10 times no matter how hard i'm accelerating.

Anyway on to other questions. My car shakes at idle and i've already adjusted the rack dampner bolt in the IP. I seemed to have gotten it as good as its going to get with an adjustment. Maybe I need to replace the motor mounts? When it is 90+ outside and the engine is up to normal temp it starts to shake but not as bad as it shook before the adjustment. It was too the point where I couldnt write anything while in the car. Do I need to replace the bolt? It is the gold colored one. I also checked the ALDA and noticed that it had been messed with by one of the PO's. BTW, the car is getting about 20mpg mixed hwy/city driving. I loosened the lock nut and put a screwdriver on it and it seems to be turned all the way out already. I turned it in a little and lost the little (1/2 turn CW) performance the car had left so I put it back to where it was. The car seems to run decent for around town driving, but compared to other MB diesels i've driving it seems like it should run a little better. In 1st gear I can defenitely feel the turbo. In 2,3,4 its a bit hard to notice. Could I have a leak somewhere? This is my first turbo/diesel powered car and i have much to learn.

One more question for now. My car leaks alot of oil. What are the common culprits for this? I know I could use a valve cover gasket and a oil return grommet but these areas dont seem like they leak fast enough to make such a mess on my driveway.

Sorry for such a long post and numerous questions. I've searched the forums but havent found too much info that is helpful other than the info on the B2. :-) Any help would be greatly appreciated.

braverichard · #2 10-19-2004, 06:49 AM

Firstly, welcome to the club. I hope you enjoy your 300SD. I'm certainly enjoying mine.

Regarding your oil leak, your leaks could be coming from any or all of the following areas: oil pan gasket, transmission pan gasket or the rear engine seal. The rear seal especially could easily become a huge leak.

bill murrow · #3 10-19-2004, 07:19 AM

I had the same hard shifting problem and it was a plugged vacuum line to the tranny. Seems to me I traced the line from the modulator--drivers side of tranny, green color thingie-- under the hood you'll find that the line from modulator fits into a "T". Thats where mine was plugged. Cleared it and the hard shift went away.

Try a search on "banjo fitting" or "banjo bolt". I have read somewhere this fitting can get stopped up causing lack of power. Lack of power would cause your lower fuel mileage. ALDA will probably need adjustment after cleaning the banjo fitting. Power should be smooth and you should not feel the turbo "kick".

Motor mounts are very common problem it seems and sounds to me like you need them. I bet it shakes harder when the a/c or defrost is running, right?

Welcome--I'm fairly new too and have found this site to be a great tool. GREAT job on th B2. Thats something I've read about here and no way would I attempt to dig that deep into the tranny. Haven't had the need--yet.

Cheers,

Bill

bill murrow · #4 10-19-2004, 07:23 AM

One other thing---when you replace your valve cover gasket, adjust the valves. A bad valve cover gasket tells me the valves have not been serviced.

Cheers,

Bill

1985 300SD Sady · #5 10-19-2004, 07:38 AM

Before you rip apart the whole car, I would rig up a remote starter switch (The 1st and the 4th screw in the black starter box on the inner passenger side fender) crank the car over, and see where it is coming from. Then pinpoint it, and go from there.

Welcome, I just bought my 300sd about 2 months ago...

tjohn · #6 10-19-2004, 08:06 AM

This engine likes to rock and roll. You may well need a new rack pin, even though the gold one is the updated version. Before I went to that though, I'd look hard at the motor mounts and the engine shocks. On mine I still had some vibration after doing the enine mounts. Turned out the shock mount had given way.

Although, if your injectors pop at widely different pressures this will have a definite negative effect on engine vibration (and probably mileage too).

Pete Burton · #7 10-19-2004, 08:20 AM

I "repaired" a trans that I have in my 82SD now by replacing the B2. Same 4-3 clunk and 1-2 chirp. If I dial back the modulator to ease the 1-2 I get 2-3 flare. Wish I knew how to fix it.

But I still love the car

bill threlkel · #8 10-19-2004, 08:25 AM

Welcome to mercedes shop, one other place to check for oil leaks is the turbo drain tube. It has a rubber seal and o ring that goes in the top of the pan below the turbo. I have replaced them in both my cars. That was a big source of leaking.
Bill

bill murrow · #9 10-19-2004, 02:18 PM

Quote:

Originally Posted by Pete Burton

I "repaired" a trans that I have in my 82SD now by replacing the B2. Same 4-3 clunk and 1-2 chirp. If I dial back the modulator to ease the 1-2 I get 2-3 flare. Wish I knew how to fix it.

But I still love the car

Doesn't everyone have the flare thing? The last 2 cars I've had flared and I did a ton of research here and found most everyones tranny has the flare thing going on.

Cheers,

Bill

pawoSD · #10 10-19-2004, 02:33 PM

Mine never flares unless it is real cold, after about 5 mins of driving its gone. My tires only churp if I lay the pedal to the floor, even then, my new tires (goodyear assurance) are almost impossible to make lose grip, even when its wet. I used to have futura's and they always squeaked and spun out, it was annnnoying.

BrierS · #11 10-19-2004, 02:40 PM

Though a different beast, my '87 300TD flared until I found/fixed several vacuum leaks and/or the result of Trans-X, a couple hundred miles and then fluid & filter change to Syn. It now shifts smooth w/o the flare. Now, the '84 300D Turbo is still at the point it shifts late (delayed) and HARD. Still need to troubleshoot that one.

kmaysob · #12 10-19-2004, 03:26 PM

"K1 spring kit"

what is this kit?

Pete Burton · #13 10-19-2004, 04:28 PM

As for oil leaks, honestly the first thing to do is really clean the engine and engine compartment. It's highly probable you will have several sources and you will immediately be able to see which is worse than others. To see what is related to crankcase pressure, compare just idling to running hard under load. Engine blowby when excessive drives a lot of oil leaks

Hatterasguy · #14 10-19-2004, 06:40 PM

Relace the engine mounts and engine shocks (if the SD's have engine shocks) they will make a big difference!

ascalise · #15 10-19-2004, 11:29 PM

Where is the cheapest place for motor mounts and shocks? I noticed today that the top of the mount for the engine shock is either worn, torn, or missing something. The shock just flops around in there. I put a huge pry bar in there when it was idling and it stopped most of the shaking so i'm sure that if i replace shocks/mounts and the rack dampner pin i should be able to cure it. Just not sure on the shock mount or whatever you call the part where the top of the engine shock mounts. I havent seen that part listed anywhere.