More good info, thank you again:):)

As encouragement to do the job yourself, I was impressed how straight forward our rebuild was. I took my time but with the parts in hand I think I could redo the job in 4-6 hours. Most of my first time was in being over-cautious to not make a mistake. The rebuild is certainly a job for someone with the interest to do it.

Jim W.

I checked the vacuum pressure yesterday on the mainline before the booster and got a steady 21. I guess this means the pump is fine?

you know your vac pump is bad when you turn your ignation switch and the car does not go off....

Then you go to the junk yard get another and bam your back in business. I just did it last week. junk yard vac cost 13 bucks.

You'll know your vac pump is toast when you can't stop at a railroad crossing!:eek: Then your car goes to the junk yard and some other sucker can buy YOUR old pump for 13 bucks.:D

Power brakes are power asissted, you just push harder and the car stops.

Vacuum pump time-bomb.....
 

This thread got me worried....... so I pulled the pump and the lower(engine side) spring base was tearing away from the shaft & wearing into the bearing bosses and had worn through the spring shaft about 1/4 of the dia....this thing was about to grenade....slightly low vacuum (due to weaker return spring length)...but no noise or other symptoms....bearings were intact....I have good parts from other pumps for the rebuild ....

Found new 626 SKF bearings at motion industries (about 13 bucks each).....these are the ones that were stock bearings in this pump.......(Thanks Beagle)

Will post pics soon to accelerate worry factor for these old pumps.....

Lucky you checked,:eek: what car?

Old age vacuum pump
 

1980-240D ...Put new diaphragm & valve kit in about a year ago...did not pay close attention to the spring base...but will now...this may be what is letting go on these....It would get the bearings probably and would wreck the cam assy....that spring is very strong to be contained by that thin collar....

I will check for cracks routinely now...may beef it up with a 309-16 stainless rod weld just for peace of mind....the plate does seem to be thin for all of that spring pressure...pics coming soon....
I wish I could find a belt driven external vac pump that would attach somewhere on the engine....

Many thanks to all the vacuum pump worrying hand wringers on this site...saved my bacon for sure.....!

great info
 

Hey guys,
Was reading this thread with great interest. My 1994 MB S350D recently started losing vacuum assist on the brakes. My first MB, so not really familiar with causes. Been researching and seems my vacuum pump is going too. Yesterday I started hearing this loud crackling sound coming from that area. :confused: Does that ring a bell with anyone? Can anyone help me with a direction to find rebuild parts for that pump?
Thanks I really appreciate the help and the posts!
Nick

Vac pump failing
 

Better get that pump off quick before it frags the internal werks....
If it is making noise...something is coming apart.....If that one has a mechanical pump...

egerman parts carries the rocker arm with bearing in a repair kit but it is $261. Sounds like tracking down the bearings and installing them in the old rocker arm is the way to go if it isn't too difficult.

-Jeb

And ********az has whole pumps (rebuilt?) for $257.

Vacuum Pumps
 

Saw pumps from (GermanStar Parts) for about $179.00 + refund core charge...
A forum member put one on his 300D and reports it is working fine....Less expensive than some complete rebuild kits...

Thanks!!
 

Thanks guys, you're the best!!
I took your advice, moved the MB to the shop and sure as heck, first time it wouldn't shut off, way low vacuum I guess. I'll check out the rebuilts.
Thanks again,
Nick