Temporary shut-off fix - Page 2 - PeachParts Mercedes-Benz Forum

David Dodge · #16 09-24-2002, 11:30 PM

Driving to Dallas area doesn't sound like a bad Idea. My son lives in Norman, Ok. It's not too far from there. It would be a real cool thing to have someone show me a few tricks about diesels.

#17 09-25-2002, 07:01 AM

David,

Don't worry, it won't kill you. What would be real handy for you at this point is a MityVac. If you could borrow, beg or buy one, it is a hand actuated vacuum pump that you can use to troubleshoot with.

Start by drawing a vacuum on the shut off valve. Since it works with your current method, I'm quite sure it will work with the vac source, but check it anyway.

Then apply vacuum to the lines going through the firewall at the oil filter housing. Find one that won't hold vacuum and trace where it goes. I fully expect it will go to the drivers door. Lock the door and see if it now holds vacuum, if it does the problem is further down the line toward the locking diaphragms. There is a diaphragm at each of the other three doors, one at the fuel tank door and one at the trunk latch. If you find the leak to be further down the line from the drivers door, go to the right rear door and check it. If the output from that diaphragm holds a vacuum, that means the fuel tank door and trunk are okay. If not then keep going down the line.

Good luck,

#18 09-25-2002, 01:36 PM

one more idea on the vacume locks... I would have someone lock your drivers side door while you listen to the trunk for a whrrrr sound
if you hear that then the pump is working.
on my car it became disconnected and didnt work
I cleaned the plug and hooked it back up and volia auto door locks.
it's also possible the main "yellow" air line going to the pump came undone
check that as well...
the pump is located under the floor panel where the spare tire goes, it'll be a triangle shaped thing covered in thick insulation foam only 2 bolts hold it in place.

Jeff

#19 09-25-2002, 02:27 PM

Sorry Mr. Shepherdson, the 123 car that David is working on uses a mechanical vacuum pump on the front of the engine. The 124 and the 126 like you have use the electrically driven one.

I wouldn't correct you, except I would hate to see David get confused since he's just starting on this process.

I'm sure he appreciates your suggestion, though.

Have a great day,

David Dodge · #20 09-25-2002, 02:47 PM

You're right..... I am appreciative. If you guys were here I would hug you like they do that man who installs direct TV on those commercials.

#21 09-25-2002, 04:16 PM

David,

I'm an old GI, country raised, redneck Texan, so no hugging allowed.

We will, however, help you work through the problem.

Have a great day,

David Dodge · #22 09-25-2002, 07:29 PM

I can't believe it. I have read so many threads about the problem being in the shut off valve and or leaks around the oil filter, I was concentrating on it being there and after last night I thought I would be tearing into the door lock vacuums.

I happen to run into a stranger who had a 1984 300D and I asked him if I could look under his hood to see what a working system looked like. It took about 2 seconds to see that my previous owner had let someone try to fix things in there and they had broken the nipple off of the Tee that comes off of the main line from the booster and had a small screw in the other one. Being this was the first Mercedes I had ever driven in, all that stuff looked like is was supposed to be there like it was. They had the one single nipple put back on with supper glue and it was getting very little vacuum anywhere through out the car because it was clogged with glue.

Well of course no one around here has that part so I went to autozone and got a F-shaped vacuum fitting (3/16) and drilled a hole in the place where one of the nipples was supposed to be. The F-fitting fit snug because I tested it first on something else before I drilled into the fitting on the car. I think it would have stayed there but I put some electric tape around it just to make sure.

I hooked all of the lines up like the other guy had his, and sure enough the engine shut off when I turned the key off. I had door locks and the trunk locked and the gas filler door all worked too. I can't tell you how happy I was when all of that stuff worked like I've been reading it should.

I'm going to take some digital pictures of how all the vacuum lines are supposed to look like, as soon as I get rid of the temporary F-fitting and back with the orriginal. Maybe I can save the next poor #$%@# rookie like me, some time and pain in the future.

Many, many thanks to all who helped. I will try to do the same someday.

Palangi · #23 09-25-2002, 10:08 PM

Somebody will correct me if I'm wrong, but I think that is (was) a metered orifice. Too much vacuum there could cause excessivly smooth shifting, which wears out the transmission clutches. I think the proper fix is to replace the complete booster line (which isn't as expensive as you might think).

David Dodge · #24 09-26-2002, 12:01 AM

Can you tell me more about replacing the complete booster line? Are the ends difficult to remove and replace. Are they crimped on somehow? Oh... I just looked a picture on Fastlane. they go on like plumbing would it looks like!

Thanks

Piotr · #25 09-26-2002, 12:10 AM

what, LarryBible, afraid of a little PC, crystal New Age, I'm-your-MB owner-bro a-hugging and a-kissing???? and a former GI?? Shame '

'

#26 09-26-2002, 08:39 AM

David,

The line is a ten minute job. There are fittings on both ends, I think 19MM. Just wrench them loose, remove the vacuum lines from the tees, wrench on the new one and replace the vac lines on the tees.

Palangi offered the correct warning though. One of the tees in the original line had an orifice. Some of the replacements have no orifice on the front tee, they are wide open, too much vacuum. Others are closed off and must be drilled out with a 1/16th " bit.

Good job,

David Dodge · #27 09-26-2002, 09:50 AM

Ok, I'm not going to panic yet! I've gone from no vacuum, to now probably too much vacuum, if I understand you guys correctly.

Would you happen to know how much vacuum is considered too much vacuum? The replacement from fast lane looks to be the same, but doesn't say anything about orifice sizes or one nipple being blocked, requiring 1/16 inch drill out.

I'm in the process of getting the CD's and got the mity-vac too.

Thanks again....Hope you guys look in on me ever-now-and-then like you have been and watch this saga through to the end.