Oh, I was thinking of my 616s, what does gear 104 drive I wonder? Maybe nothing if its a turbo:confused: I know if I was doing that job, I'd wind up retiming everything:)

Apparently that gear doesn't do anything on the turbo engine, but they use the same part.

Mine is now back in one piece with everything replaced. The engine sound is gone and it is once again a happy car, just in time to drive about 2000 miles next week. Now I have to install the cruise control amp and actuator that just arrived from GDL.

BTW, the tech ended up having to retime it too, the IP moved when he pulled it apart. He ended up putting almost two days into it.

:confused: What is this vac. pump everyone is talking about. My 1987 300DT has 151,400 miles on it.

Unlike a gasoline engine, diesels do not create vacuum in the intake manifold so they have a mechanical vacuum pump to support the power brakes and other components. It looks like this, and is bolted to front of your engine:

http://catalog.worldpac.com/mercedesshop/sophio/wizard.jsp?partner=mercedesshop&clientid=catalog.mercedesshop&baseurl=http://catalog.peachparts.com/&cookieid=1CQ0J3JZ426P1BAXNL&year=1987&make=MB&model=300-DT-002&category=All&part=Diesel+Vacuum+Pump

The problem is, if they fail they can cause significant engine damage by getting small parts into the timing chain area. The design of the pump on your engine has be upgraded over the years, it's not a bad idea to make sure you have the latest version installed. If you search on vacuum pump here, you will find a few ugly stories.

Ah good, your back on the road. I think you're lucky to have a mechanic that dealt with this and got it done in two days. You'll have a much better trip without that noise for company;)

He's good, he heard the noise from about 10 feet away and told me exactly what it was. His tech really worked his butt of to get it finished by friday afternoon. I really didn't want to have to worry about it coming apart while I was driving, I probably would have taken another car if he couldn't get it done.

I read that Craig's mechanic had somehow moved the IP when the vac pump was removed. I think on my 603 the bolts that hold the Vac Pump also are Injection Pump fasteners that are loosened for timing??? Is that right???

If so, how do I avoid messing with my pump timing when I change the Vac Pump?

Mine went bad with 170k showing iirc, although I always wondered if the mileage on that car was correct. I bought it from a small used car dealer.

Tom W

that part 105 is the coupler that attaches to the ip right? I had one of those wear out on my 74 240d. It was really hard to figure out because the ip timing kept getting off. NObody had ever heard of one going bad before. The small indie garage in cincinnati figured it out finally and used one off a 60s 280e iirc.

Tom W

Your IP MAY have a place for a "locking pin" someone will chime in. Its good to learn how to do the timing, not really a big deal once you go through the learning curve and do it once, epically if you have the "pin"

Thats a good thing too keep in mind, maybe an oil passage got restricted and caused the problem.

Yes, 105 is that coupling to the IP.

Just to be clear, you can remove the vacuum pump without affecting the IP, he actually had to remove the IP timing device (behind the vacuum pump). That's the thing that drives both the IP and the vacuum pump and controls the IP timing advance based on engine speed.

Ok... I wonder why he removed that? I've changed a vac pump on a previous 123 300d and I never removed the IP timing device.

Also, on the 603 in my 124 300d I see that the Vac Pump is just bolted on with other bolts. Not the three bolts that are loosened to adjust IP timing. So shouldn't be too bad.

I really cut my arms up getting the fan off though. That 8mm allen bolt is a pain to loosen. NO CLEARANCE!!! Ouch!

I found a great way to break it free though. I taped an 18" piece of conduit as a breaker bar to my allen wrench, supported it well and had my wife click the motor over very quickly. I had to be VERY careful of course. But it worked great.

Actually that engine was the most worn one we have encountered by far. Everything that could wear out in one pretty much had to be redone, including all the oil pump parts.

The car itself was very very clean, a california car, and it showed 50 some thousand but who knows it was a 99k odo on the 115 body and it could have been turned over many times.

When I got it it had a holed piston iirc, with one cylinder that was down. A local indie who enjoys a good reputation but whom I have always fealt leery of had replaced the ip but of course that had not solved the rough running.

Tom W

It was the IP timing device that was the problem, it had too much axial free play so that it was getting pushed back and forth by the vacuum pump. I had a little clank sound (I thought it was a loose valve) when it hit the thrust bushing behind it.