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  #1  
Old 03-31-2018, 04:48 PM
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Lightbulb Om621 still no vacuum after pump rebuild

I tracked down a rebuild kit and rebuilt my vacuum pump on my 66 200D. It seemed pretty straightforward, diaphragm was torn, replaced that and the 2 check valves! Easy, but still no vacuum. I'm wondering if my driver plate is worn or the roller lifter is worn down? I included photos and hope someone has any experience with this!

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Old 03-31-2018, 05:03 PM
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Pictures aren't showing up. Not sure how silimat the om621 pump is to the early om617pump, but on the 617 there is also the external brass check valve in addition to the internal ones. Does yours have this? And if so, are they good.
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Old 03-31-2018, 08:06 PM
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just seen that. lets try again.... i do not see any check valves external to the pump. the only thing i can think of is if the bolt that holds the diaphragm to the "roller lifter" isnt long enough or not spaced correctly..........ugh
Attached Thumbnails
Om621 still no vacuum after pump rebuild-vacuum-pump-2.jpg   Om621 still no vacuum after pump rebuild-vacuum-pump-3.jpg  
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Old 03-31-2018, 08:56 PM
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wait, are there suppose to be bolt heads or something on that rotating plate? the om617 engines have bolts on top of that plate and im wondering if theyre what actuates the diaphragm in and out? it also looks like the om617 and om621 pumps could possibly interchange??
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  #5  
Old 03-31-2018, 09:25 PM
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It looks like your injection timing device is missing the vacuum pump drive plate. There is no chance that the pump is going to work with that part missing.

https://dq4zp01npifg0.cloudfront.net/sites/default/files/imagefield/product/dslvacpumpdrive.jpg
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Last edited by tangofox007; 03-31-2018 at 09:36 PM.
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Old 03-31-2018, 10:19 PM
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That looks like a om617 engine, I can't find any photos of an Om621 with the pump removed....
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Old 03-31-2018, 10:20 PM
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617 or not, if you don't have the rollercoaster cam attached to the injection pump, there's nothing to cause the cam follower to oscillate on the vacuum pump.
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Old 03-31-2018, 10:30 PM
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And looks like the timing device is worn as a result of the VP bearing having to slide along it. Hate to think of the swarf thats put into the oil...
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1984 240TD>300TD 121,000 miles, *gone*
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Old 03-31-2018, 10:53 PM
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I know, but where on earth did it go (previous hack got rid of it?), and what does the roller-coaster cam look like on the Om621, can only find 617 stuff still. Factory service manual is lacking in this area
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Old 04-01-2018, 02:07 AM
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Quote:
Originally Posted by Ryancoolwind View Post
I know, but where on earth did it go (previous hack got rid of it?), and what does the roller-coaster cam look like on the Om621, can only find 617 stuff still. Factory service manual is lacking in this area
I'd be willing to bet they're the same part numbers. Remember the 617 is just the bored, stroked and extra cylinder version of the 621.
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1978 300D, 373,000km 617.912, 711.113 5 speed, 7.5mm superpump, HX30W turbo...many, many years in the making....
1977 280> 300D - 500,000km+ (to be sold...)
1984 240TD>300TD 121,000 miles, *gone*
1977 250 parts car
1988 Toyota Corona 2.0D *gone*
1975 FJ45>HJ45
1981 200>240D (to be sold...)
1999 Hyundai Lantra 1.6 *gone*
1980s Lansing Bagnall FOER 5.2 Forklift (the Mk2 engine hoist)
2001 Holden Rodeo 4JB1T 2WD

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  #11  
Old 04-01-2018, 09:42 AM
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Good now I just need to find one! Which is usually the hardest part in fixing these cars
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  #12  
Old 04-01-2018, 11:56 AM
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Take a good look at the picture of your 621 timer. I am not seeing any bolt holes with which you could bolt on a Vacuum Pump Cam Drive Plate.
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Old 04-01-2018, 10:10 PM
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I found my Book; Service Manual Maintenance, Tuning, Unite Reploacment Diesel Engines OM 636 and OM 621.

None of the pictures in the book show a Vacuum Pump installed and none of the pics of the Timer show bolt holes for or the cam to actuate a vacuum pump.
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Old 04-02-2018, 07:25 AM
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That is strange..... How else could a diesel have power brakes beside hydroboost??
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Old 04-02-2018, 01:48 PM
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Quote:
Originally Posted by Ryancoolwind View Post
That is strange..... How else could a diesel have power brakes beside hydroboost??
Gassers use manifold vacuum. I believe your Engine has a similar butterfly valve that creates manifold vacuum used for the Pneumatic Governor. That could also be used with the power brake booster if the manifold vacuum is high enough.

It is also possible that that Engine did not come with the Car. The pictures in my book are from 190Ds. Did 190Ds have power brakes?

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