Gave some love to the 300D yesterday - PeachParts Mercedes-Benz Forum

tip · #1 06-22-2012, 03:42 PM

So, I don't post on here too much because a search yields all the info I could ask for!

I thought I would share some work I did on the 300D. My girlfriend primarily daily drives it, almost 500 miles a week. The car has been shifting harsh ever since we got it, which I have been scratching my head with for a while. The other issue that it was having was low power on the freeway and a rough idle.

When trying to diagnose the shifting problem, I found the vacuum switch levers were both completely broken off!

Thankfully I was able to just get the levers themselves off Fastlane, so I replaced those first.

old vs new:

installed:

I installed them back on the car, cleaned up all the old grease off the cam wheel and test drove. Shifts like butter now! Shift timing was obviously improved as well, since the vacuum switches where essentially useless without good levers. Total cost, under $5. Best $5 I've ever spent, on ANY car I've ever had. One of the reasons we got the car so cheap is because of the harsh shifting... if only the PO did this repair. Apparently he had a bunch of shops trying to diagnose the problem. Its nice what a little research will do for you!

Next up was the low power issue. It was time for fuel filters so I thought I would start there. No record of a diesel injection service so right now was the best time for a diesel purge. Also found the primper pump was seeping diesel so I ordered up a new style pump.

Old primer pump:

old vs new:

Diesel Purge (local Napa actually had it for 8.00/can)

my sobe setup:

running:

Makes you really appreciate how much these cars sip diesel. The two bottles took almost an hour to burn... even at different RPMs (under load, WOT, idle, etc). I was a little leery of this procedure since I've been around TDI's for a while and never seen it done. But it is all over the web and thought it couldn't hurt.

Car didn't smoke at all but halfway through the first can I could already tell it was running smoother. By the time it was done it was hardly shaking at all. Got it hooked back up, put on new spin on and inline filters and took her around town. Runs much better! Throttle response is back, quick start up, and most importantly, no loss of power on the freeway. Cost: less than $30. Again, money WELL spent. This will hold the car over til I do Bosio nozzles.

I also checked out the ALDA system, which was surprisingly clean as a whistle, no soot whatsoever.

Thought I would share what less than $50 can do to make these cars feel new again. Now for a valve adjustment, anyone willing to loan me some wrenches?

Or will my regular 14s work?

gatorblue92 · #2 06-22-2012, 05:08 PM

Regular 14MM wrenches will work but its super easy to get a pair of cheap Harbor Freight wrenches and bend them yourself.

neumann · #3 06-22-2012, 10:23 PM

Regular wrenches work just fine. 79mercy did my valve adjustment last week and he had no issues with straight wrenches. He said he actually wpreferred them.

VW1300 · #4 06-22-2012, 10:28 PM

Thanks for posting the pictures! What a beautiful car.

Diesel911 · #5 06-22-2012, 11:04 PM

Except for being a source of a Valve leak the little Valves with the worn levers have nothing to do with the Transmission itself. The Valves are to control the EGR.

charmalu · #6 06-23-2012, 01:07 AM

On my bro in Laws 82 240D, one is for the EGR and the other is for the transmission to shift.

Here is the part #. for the lever.
OES GENUINE Vacuum Valve Lever 3/2 Way,W0133-1640593 - PeachParts

TIP, those are some good pictures and write up.

Charlie

euroamg · #7 06-23-2012, 12:25 PM

Diesel Purge works wonders on a diesel engine.. We use those in our diesels for a very longtime already. Great product. Everyone should do it on their diesels..

tip · #8 06-23-2012, 01:29 PM

woops, double post.

tip · #9 06-23-2012, 01:31 PM

Thanks guys. Wasn't sure if anyone would read my post or not, but figured everyone likes pics

Quote:

Originally Posted by Diesel911

Except for being a source of a Valve leak the little Valves with the worn levers have nothing to do with the Transmission itself. The Valves are to control the EGR.

Everything I've read said they help provide input to the trans. Could be wrong though. Didn't even think to trace the lines myself. As far as EGR, that makes sense too. But the car shifts WAY better, so I don't know if I believe it has nothing to do with the transmission.

Yak · #10 06-23-2012, 04:30 PM

Quote:

Originally Posted by tip

Thanks guys. Wasn't sure if anyone would read my post or not, but figured everyone likes pics

Everything I've read said they help provide input to the trans. Could be wrong though. Didn't even think to trace the lines myself. As far as EGR, that makes sense too. But the car shifts WAY better, so I don't know if I believe it has nothing to do with the transmission.

Vacuum (or leaks) affect transmission? Nah....(it's only 49 pages long, plenty of opinion, fact, data, anecdotes)

It's CRITICAL... how you set your transmission's vacuum system on your diesel MBZ...

tip · #11 06-23-2012, 04:35 PM

I meant these particular vacuum switches. I've made the rounds through that thread many times.

Yak · #12 06-23-2012, 05:12 PM

Quote:

Originally Posted by tip

I meant these particular vacuum switches. I've made the rounds through that thread many times.

I'm agreeing with you. If repairing the levers affected the position of the 3/2 valve to stop a leak, then they probably improved the shifting.

I think this is consistent with diesel911, but maybe phrased differently: the levers/valves don't control shifting, but if they're leaky for whatever reason, they can affect shifting.

Regardless, nice post, nice pics. Your engine bay looks clean and sweet.

Is that an oil pressure line disconnected near the Sobe bottle? Just asking...

indybenz · #13 06-24-2012, 10:37 AM

Side Note: I was under the impression, from my reading on this forum, that the primer pump on the OM617.952 had to be replaced with the original style pump. True?!

tip · #14 06-24-2012, 01:59 PM

Quote:

Originally Posted by Yak

Is that an oil pressure line disconnected near the Sobe bottle? Just asking...

Yes, the gauge was leaking and it was disconnected by PO. I have a new gauge put in.

Quote:

Originally Posted by indybenz

Side Note: I was under the impression, from my reading on this forum, that the primer pump on the OM617.952 had to be replaced with the original style pump. True?!

From all I read is that if you're running WVO or bio you want the original style due to larger pumping stroke. I run reg diesel so it didn't really matter to me and I like the newer design.

Sev · #15 06-25-2012, 04:08 AM

good tip on the levers, i'm going to buy myself a pair and replace them. cheap five minute job to improve shifting maybe