A little over a month ago, I bought a 1975 300D. I've had to rebuild the vacuum pump and replace the diaphragm 3 times.

The first two times I had this issue it was right after I slammed the brakes during traffic. No explanation for what went wrong this third time. I was driving and felt the brake booster go. Upon arriving at my destination, the car would no longer shut off by turning the key off.

Any help would be great!

Thanks!

I have read with the piston style if the intermediate shaft has to much play it was slap back and forth and destroy them. Maybe the same thing happens to the diaphragm type?

Could be due to over tightening the center nut of the diaphragm.

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1985 Euro 240D 5 spd 140K
1979 240D 5 spd, 40K on engine rebuild
1994 Dodge/Cummins, 5 spd, 121K
1964 Allice Chalmers D15 tractor
2014 Kubota L3800 tractor
1964 VW bug

"Lifes too short to drive a boring car"

Thanks

I'll take it easy on the next round

the torque spics are listed in the instructions, but I, and most folks, dont have a torque wrench that measures that low. be sure and use the blue thread lock. At least the diaphragms for these early pumps are allot cheaper than the rebuild kits for the newer style pumps.

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1985 Euro 240D 5 spd 140K
1979 240D 5 spd, 40K on engine rebuild
1994 Dodge/Cummins, 5 spd, 121K
1964 Allice Chalmers D15 tractor
2014 Kubota L3800 tractor
1964 VW bug

"Lifes too short to drive a boring car"

Thanks for the help everyone!

I talked to the mechanic that did a lot of the work on this car prior to when I bought it. I explained how the diaphragm keeps tearing. He recommended I replace the the vacuum pump.

What do you guys think? I found a place that has used ones for $175

Probably interchangeable with those up to 80 or 81. Easy to tell by checking parts at parts suppliers like this site. If you decide on a used pump 175.00 is way over the top..

Pick and pulls or parts for sale in our section will be a lot cheaper. Examining your current one for obvious wear though would be the first step.

It was your mechanic that did the diaphragm replacements?

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1985 Euro 240D 5 spd 140K
1979 240D 5 spd, 40K on engine rebuild
1994 Dodge/Cummins, 5 spd, 121K
1964 Allice Chalmers D15 tractor
2014 Kubota L3800 tractor
1964 VW bug

"Lifes too short to drive a boring car"

no i did the replacements myself

Well if thats the case, why dont you replace the diaphragm again using red thread lock and make sure the large "washer" is facing the right way, if turned around it can cut the diaphragm. You might as well, you can buy allot of diaphragms for $175, and by now you must pretty fast getting that pump off. Be sure to just snug the center bolt, coming as close to the proper torque as you can.

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1985 Euro 240D 5 spd 140K
1979 240D 5 spd, 40K on engine rebuild
1994 Dodge/Cummins, 5 spd, 121K
1964 Allice Chalmers D15 tractor
2014 Kubota L3800 tractor
1964 VW bug

"Lifes too short to drive a boring car"

Thanks!

Does anyone know what the proper torque is for that center bolt?

Repair Links
http://www.peachparts.com/shopforum/forumdisplay.php?f=82
http://www.peachparts.com/Wikka/DoItYourSelf

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84 300D, 82 Volvo 244Gl Diesel

ipernity: Vacuum pump membrane - by Michiel 2005

http://www.peachparts.com/shopforum/diesel-discussion/326979-vacuum-pump-diaphragm-repair-car-bench.html


You also need to inspect for in / out slack - slop of the timing device shaft bearing.
If this device is moving = the stroke changes length = excess STROKE = stress on the diaphragm.





Early Mercedes vacuum pump rebuild - YouTube

http://www.peachparts.com/shopforum/diesel-discussion/318203-vacuum-pump-diaphragm-replacement-beginners-perspective.html


Note to other members, here is the type of vacuum pump he is working on.


.

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1985 300SD
1983 300D
1984 190D
2003 Volvo V70
2002 Honda Civic

https://www.boldegoist.com/

As per the FSM.
NOTE: Self-locking hex nut may be used only once.

Mount washer. then lightly screw-on self-
locking hex nut and move piston against
housing bottom by turning back screw spindle.
then tighten hex nut to 9 Nm.


Charlie

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there were three HP ratings on the OM616...

1) Not much power
2) Even less power
3) Not nearly enough power!! 240D w/auto

Anyone that thinks a 240D is slow drives too fast.

80 240D Naturally Exasperated, 4-Spd 388k DD 150mph spedo 3:58 Diff

We are advised to NOT judge ALL Muslims by the actions of a few lunatics, but we are encouraged to judge ALL gun owners by the actions of a few lunatics. Funny how that works

I replaced the vacuum pump on a 74 - 240D with a piston type pump from a 84 300D. End of my pump problem. The diaphragm pumps don't like extended high speed.

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1984 300SD turbo 126
"My true love"

God made me an atheist and who am I to question His wisdom