New owner of 1978 300D and loving this forum

[Island300D]

Well, my first post here, everyone starts somewhere. I'm pleased to announce that my family has purchased our first Mercedes, a beautiful 1978 300D that I have begun to lovingly tune up. She only has 189K and has been garaged her whole life and treated better than a fancy pet.

Before buying her last week I googled Mercedes, found this list, and have been absorbed in it ever since. I've probably spent two hours a day reading posts on the W123 chassis and everything else Mercedes.

Let me say right up front: This is by far the most helpful and thorough and wonderful forum I have ever used, and I have used many. I am also the full-time caregiver to a sailboat with a diesel auxiliary and so am part of various boat forums and miscellaneous other things. I am completely thrilled that any thing I could ever want to do on my 300D has been done and discussed on this forum. We all know how invaluable it is to share wisdom of this sort.

Having had the car for about five days, I have already adjusted the valve timing ( I learned here about the wrenches and bought two $3 14mm at the local hardware store, heated them with my propane torch and bent them, and they worked perfectly!!! Thanks to the person who suggested this as it beats the pieces out of buying "official wrenches" for 12X the price), replaced and repacked the front bearings, changed most all the fluids, replaced all the old and original fuel lines (they crumbled in my hands) and filled up with my first tank of B20.

We have been casually looking for a good used diesel for over a year in our search to go biodiesel and are in heaven at having found this one. Now that I've swapped out the fuel lines I will start running B99 during the summer months here (San Juan Island, Washington) and a blend in the winter. Every single dollar I give to corporate oil and our own and other dictatorships makes me actively sick. Not to mention the important eco-benefits of biodiesel. Will look into VO later too.

So please let me end by saying THANK YOU. I've already benefited enormously from all the people who have taken the time to post pictures and explain their experiences. I look forward to being an active member of this forum as there is still so much I have to learn.

Oh, and I have already supported this forum and bought some tune up parts through the shop. Good price and fast service this first time.

[Jeremy5848]

Sounds like a nice car -- pictures, please!

I'll wave as I go past San Juan next week on my way to Mt. Vernon for the Highland Games.

Jeremy

[unkl300d]

B here or B

pics

[Island300D]

I agree that if I weren't getting Beta here I'd be . I'll try to get some pics soon, she's a beauty. Next project is to repair the just failed trip odometer. I've read the many posts and seen the diesel giant pictorial. Looks straightforward. Have fun at the Highland games!

[rs899]

Welcome aboard. Nice to see you have done some digging around on here on your own. I, for, one get a bit tired of the newbies asking the really basic questions. The COLLECTIVE wisdom of the group over the 7 or 8 years of this forum trumps anyone's personal knowledge.

Rick

[Island300D]

Rick, you are so right about the collective wisdom trumping any one person's knowledge. I've been fixing cars all my life and was lucky enough to have a mechanic as a dad, and so I'm a do it myselfer to the first degree, and by nature, would rather make mistakes than pay someone else to make them for me. For this reason, this forum is indispensable. I get to take a few minutes and read how 10 different guys dealt with something like my broken odometer, and pick the technique that rings most true.

Projects for this week are to remove the oil pan and clean out any and all crud after running her hot and draining the new oil I just put in. An engine flush basically. Also, I want to tackle removing and repacking and maybe replacing my rear bearings, having just done the front. Oh and I need to drain and flush the rear differential, which I am certain has 189K worth of original oil in it!! Again, the PO fixed everything that broke right away, and babied the car extremely well, but anything resembling preventive maintenance, which I love, did not get done.

[kerry]

Originally Posted by Island300D

Also, I want to tackle removing and repacking and maybe replacing my rear bearings, .

This is not a job to approach casually. A special tool is required. Some posters here have replaced the whole control arm rather than replacing just the bearing.

[Island300D]

Thanks again to this forum, I have learned the truth of the previous helpful post about not tackling the rear bearings lightly. Have read enough to see it is a pain in the butt. I know I could do it, skill and tenacity wise, but nothing I am eager to do. I was just going to do them as regular maintenance, but screw that idea. I've done rear bearings on Volvo's, VW's, Ford's, GM's and Toyota's, none of which were anywhere near as complicated as on this Mercedes!!

Wouldn't it be great if all the car manufacturer's got together and shared Best Practices so no one came up with with their own horrible way of doing something when someone else had already figured out a perfect way to do it? Why did Jaguar and MG ever try to do their own electrical systems? Why didn't everyone just copy the slant 6 of the Dodge Dart? And why the hell did Mercedes think it was OK to make their rear bearings impossibly hard to work on, when most every other car manufacturer has a perfectly simple and effective system for doing so? Oh well, we can't have everything!

Now I am having a hell of time getting the oil fill screw out of my rear differential! Two feet of breaker bar and the damn thing still won't budge. Oil I drained out was toast and filled with metal shavings. Glad I am doing this one...

Thanks for the heads up...

[yellowbenz]

I think this fellow's experience reinforces a common refrain here. Make sure that you can get the screw for the fill hole out BEFORE you go for the drain. Something that neophytes like myself need to be told ad nauseum.

Kevin
1979 240D manual
1984 190D manual leaking delivery valve seals parts/socket ordered and still for sale

[t walgamuth]

Originally Posted by Island300D

Thanks again to this forum, I have learned the truth of the previous helpful post about not tackling the rear bearings lightly. Have read enough to see it is a pain in the butt. I know I could do it, skill and tenacity wise, but nothing I am eager to do. I was just going to do them as regular maintenance, but screw that idea. I've done rear bearings on Volvo's, VW's, Ford's, GM's and Toyota's, none of which were anywhere near as complicated as on this Mercedes!!

Wouldn't it be great if all the car manufacturer's got together and shared Best Practices so no one came up with with their own horrible way of doing something when someone else had already figured out a perfect way to do it? Why did Jaguar and MG ever try to do their own electrical systems? Why didn't everyone just copy the slant 6 of the Dodge Dart? And why the hell did Mercedes think it was OK to make their rear bearings impossibly hard to work on, when most every other car manufacturer has a perfectly simple and effective system for doing so? Oh well, we can't have everything!

Now I am having a hell of time getting the oil fill screw out of my rear differential! Two feet of breaker bar and the damn thing still won't budge. Oil I drained out was toast and filled with metal shavings. Glad I am doing this one...

Thanks for the heads up...

The reason benz rear bearings are near impossible to service yourself is that they almost Never need any service.

And the gratitude felt by you for the collective wisdom here is felt just as strongly by me, one of the most grizzled and experienced of us. No matter how experienced each of us is there are many many things that have never been thought through before.

It is a great forum....thanks guys.

Tom W

[Jeremy5848]

Originally Posted by Island300D

Now I am having a hell of time getting the oil fill screw out of my rear differential! Two feet of breaker bar and the damn thing still won't budge. Oil I drained out was toast and filled with metal shavings. Glad I am doing this one...

Thanks for the heads up...

As was just said, the fill plug should come out first. Now you can't drive the car at all!

Try gently warming the diff cover with a propane torch. The cover is aluminum in some models whereas the plug is steel. Aside from electrolytic effects welding the metals together after 20 years there is the effect of differential (pun not intended) expansion of the dissimilar metals.

Mine wouldn't come out either. I finally removed the entire cover and clamped it to my workbench; even then the plug wouldn't come out until I scared it with the torch. Then it came out easily. I used a little Teflon tape when I put it back.

Jeremy

[Jim Wickham]

Yeah if you heat the diff cover it should come right out..

Could also try air impact gun that tends to break the bond between aluminum alloys and steel... when you put it back in make sure to use Neversieze (gooey graphite grease stuff)

We do this on our new dodge diesels with alloy rims and steel hubs. The rims come off easy each time afterwards. I'm sure it will work for the fill plug in your differential.

[rs899]

Well, if you bugger it you at least can pull the whole cover off the diff and replace it with one from a boneyard.

Don't repeat this mistake with a manual gearbox- there's no "plan B"

Rick

[vstech]

Welcome indeed to the forum!
don't forget to put your car in the signature. it's good you put in your location, but be sure and list your vehicle too. makes it simple for us to know what car you are talking about when you need help.
and I second the request for pictures.