Vacuum pump failure W210 606
 

We have been hearing ticking rattling noises coming from the front of the engine on our '96 E300 for more than a year now. Have ask every mechanic their opinion and the general consensus was that to put the car in a shop to diagnose would cost hundreds of dollars and that it is best to wait until a problem occurs. Yesterday a problem occurred; while driving cross country engine code P0400 came up, no power brakes, AC vents stopped working, shifting became hard and the intake manifold valves stopped working.

We were lucky, I hope, that the vacuum pump did not explode. The engine actually sounds better now without the rattle and the car ran great for the rest of the trip home, more that 7 hours of running hard. (The car now has 215,000 miles on the dial.)

Passed through Dallas, hours later, where there are several parts suppliers. One had the part that I now have.

Questions: Do you guys have any suggestions or advise on replacing the pump? Are there any hidden issues that I should be aware of? Is removing the radiator required?

Will post pictures of the work in progress.

Thank you in advance for your input.

Release the tension on the drive belt.
Remove the upper radiator hose and the P/S pump's pulley.

After that, it is a 15 minute job... the second time you do it.

P0400 is EGR malfunction. Would that be thrown with a failed VP?

Remove each bolt on the vac pump a little at a time so that the pump will come off parallel to the block rather than getting cocked. So loosen all bolts round the perimeter a bit at a time, round and round. It can get cocked if the roller on the pump is on the high side of the "timing device" or ramp which the roller rides on. That sentence will make sense after you see what's under the pump... Hopefully your roller and the bearings are still intact. If not, put a magnet on your oil drain plug and collect as many balls as possible. I still have one ball floating around somewhere in my engine, but I've been driving like that for more than 100K.

Rgds,
Chris W.
'95 E300D, 420K

The EGR flaps are actuated with vacuum motors.

Tip: Degrease and clean the pump and surrounding area before you start removing bolts.
Tip: Clean off every bit of old gasket material.
Tip: Clean out the bolt head sockets, if that's the style you have.
Tip: Replace every bolt in exactly the same hole.
Tip: Get a good torque wrench and use it

Thank for the help.
What is the torque pressure?
Heading out to start the R of R&R now.

... and a new gasket.

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wear on stroke curve?
 

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Assembly instructions say that the stroke curve must be replaced if worn.

Is the stroke curve in the above picture worn enough to require replacement of the lifting cam?

That looks pretty bad. Can you "feel" it?

deep end
 

You're now in the deep end, but you're not alone. I seem to remember a thread here about replacing that wavy piece on the cam. At least it didn't grenade the engine.

http://www.peachparts.com/shopforum/...w210-606-6.jpg

Flat spot on the wheel that rides on the cam?

Could be that it seized up and rubbed itself flat on the cam, damaging it too.