I am about to replace the vacuum pump in my 1991 300D2.5. This is the pump that mounts to the front of the engine. In the MBZ shop manual it says, "During installation make sure that the lift curve of drive flange is at its BDC." What does this mean???
With the new part came an information sheet that says, "Install vacuum pump only if the stroke curve is in perfect condition" I am lost, I was under the impression that this was a simple R & R job.
Does anyone have any experience with replacing a pump on a 124 diesel??

The MB vacuum pump drive is a cam -- sort of a cylinder with a wave cut in it in the long direction. The vacuum pump has a roller than rides on this cam -- the cam pushes the roller forwards, then lets it come back under spring pressure.

What you want to do is have the cam set with the low portion at the bottom so that the roller isn't pushed out -- the pump body will then fit up against the block without you having to compress the spring. If you don't set it this way, you can crack or bend the housing as you tighten the bolts that holds it to the block.

Easy to do -- don't put the bolts in unless the pump housing fits right up tight on the block without pressure. It will be obvious when you take the old one off. You will need to have a socket big enough to put on the crank pulley bolt to turn the engine -- it really isn't very easy to set it with the starter!

The other item means that if the roller was ruined on the old one, and the cam surface is bad, the new one will look like the old one shortly!

I expect it looks very much like the 123 and older diesel vacuum pumps -- I've not had it off on mine!

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

Thank you for the response. I replaced it last night and it was exactly like you said.

I'll be changing my vac pump tomorow, already bought the gasket, my question is: should i use sealant along with the gasket guys??

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Mercedes fanatic

1985 200D (w124) and totaled 190D

bumpety bump
Rly needed this answered guys!

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Mercedes fanatic

1985 200D (w124) and totaled 190D

No, install the gasket dry.

thanks alot speedy!

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Mercedes fanatic

1985 200D (w124) and totaled 190D

Hi all.... I am currently replacing the vacuum pump on a 1985 190D 2.2

Once I removed the vacuum pump, I notice that the "stroke curve" is damaged. It has scoring in the metal and is no longer smooth metal as it once was.

The Pierburg vacuum pump R/R instructions state:

"if the slightest sign of wear is noticeable on the stroke curve, the lifting cam must be renewed"

and then further state:

"the stroke curve is no longer available as an individual spare part. The complete injection adjusting device must be replaced."

Does anyone here have any knowledge of this area. I notice the original post on this thread mentions the "stroke curve", but no further discussion of it transpired.....

I am concerned that I may quickly get in over my head with timing issues and such.... If it were so simple as to remove this "stroke curve" and replace it, no big deal... but if I am getting into timing issues and complications such as those, I am concerned that my abilities and time do not permit me to continue this task...

Anyone know where to order this part, as just the "stroke curve" or as the
"complete injection adjusting device"

Does anyone know the steps for removing either of these parts and whether such a task entails having to reset the timing or any other more complicated endeavors....?

Any thoughts?

Thank you, digby

BAE systems in Sweden MAY have the part.
Telephone 46 66080161

World Impex says their MB supplier tells them they will source it from a dealer
in the EU.
TEN WEEKS delivery time.
(Their toll free number is on the attachment.)

EVERYTHING else listed is in the Russian Federation.

GSXR has on his "Website" R+R instructions and Pictures of the Process:

W124 Performance

(NOTE: the same ramps are used on all Mercedes Diesels of the "Families" OM601,OM602,OM603)

NOTE: the securing bolt that holds the Timing Ramp on is REVERSE threaded.

(This ain't a simple "screw off /screw on" procedure,you will have to take
steps to preserve your TIMING!)

Attached Thumbnails

   

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'84 300SD sold
124.128

This is just thinking out loud for a sense of what's involved and I have not reviewed the FSM -

You have to reset the engine from #1 TDC where it's easier to r&r the vacuum pump to 14* BTDC (#1) so you can lock the IP while replacing the timer.

You don't have to remove the tensioner if you remove the cam sprocket since removing the cam sprocket will give you the slack you need to slip the IP off the chain. You might have to remove the upper guide rail to avoid removing the tensioner. I don't see how removing the tensioner helps since you shouldn't rotate the cam without also rotating the engine. With slack in the chain upstream of the timer, slide a metal or plastic card along the timer cogs to lift the chain off the cogs. Go all around the timer. When the chain is free of the timer, remove and replace the timer. Oops, loosen the left hand thread bolt on the timer before loosening the chain. Don't fit the IP lock until the timer bolt is loose!. Timer clocking should be irrelevant because there are more splines than cogs on the timer <- hopefully not famous last words. Pull out the card and engage the chain in the timer cogs starting with the bottom and working CCW so as to have all slack towards the cam sprocket. If you locked the cam and didn't move the crank from 14* BTDC, you won't have affected IP timing. However, if the splines didn't align just right, you might have to bump the cam or crank a hair to engage the cam sprocket on the cam. You could remove the timer and try a different orientation. I wonder why MB didn't index the timer to the IP.

I'd note cam and IP timing before touching the chain so you have a point of reference. Set the cam alignment marks and read off the crank pulley, then set the IP lock in place and read off the cam pulley.

Sixto
87 300D

I pulled a good timing gear with an undamaged timer ramps. IIRC its the same gear across the 60x line. LMK if you'd be interested in buying

Thanks Compress Ignite and Sixto for your rapid responses.

Whew! Ten weeks is a bit of time... I found this listed as an "injection pump timer" online from pro street online. It says it's for the 1985 190D, but the part # is different from what World Impex lists on their site. Is this the correct fit for the 85 190D?

Injection Pump Timer - Pro Street Replacement Parts

I should have mentioned in my original post that when I removed the old vac pump, several pieces of metal fell out to greet me. Upon examination of the old vac pump, I find no bearings and discovered that one of the two metal rings that would house the bearings has been sheared completely off. NOTE: the metal pieces that fell out were not bearings, but part of the housing unit. bearings are gone...?

See attached images: I am trying to attach images but no luck. It asks for a URL??? Sorry, I'm new to this internet thing, sort of.

My fear is that the bearings, and perhaps other metal shavings from the housing, have wandered into the engine compartment despite the presence of the infamous "basket" that sits between the vac pump and the timing chain housing. Would this spell impending doom? Where else could the bearings have gone? I am certain that they did not just vanish into thin air as this is a vacuum pump and there would be no air present...Ha Ha.

Also:
The links to GSXR's site is a gem... However, I am not finding anything relating to the "timer ramp"/"stroke curve" replacement. There is a Pierburg pdf that shows how to tell if the timer ramp is damaged and in need of replacement under the mb/60x section, but nothing detailing the replacement of the timer ramp/stroke curve... or am I totally missing something there?

Thanks again, digby

I would definitely be interested. How complicated is the pulling and replacing of the timer ramp? Seems to be a bit more than replacing the Vac Pump....

thanks, digby

You will need the injection pump lock tool to lock the pump and I've seen a replacement of the entire gear itself before on here or somewhere else. The bolt is left hand threaded fyi.

find out if the timing gear from a '92 300D with the 2.5 om603 will work for you and ill get pics of it asap to send you.

(NOTE: the same ramps are used on all Mercedes Diesels of the "Families" OM601,OM602,OM603)

Also,YOU don't want to use the Injection Pump Locking Tool to secure the
I.P. for removing the Counterthreaded Bolt.It'll snap that little tool off in
a heartbeat.

Instead, Lock the Flywheel with the Timing Chain still on everything AND then
loosen the Bolt.

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'84 300SD sold
124.128