I'm making a new thread, in the hopes one day somebody can find the info easily.

On my new to me 180d-om636 engine. I'm having some wicked IP pump issues. Its all due to old/ bad fuel sitting in it for many years.

This has the bosch Pes4 unit-with the diaphragm on the rear.

Anyway, the rack was jammed up hard. So I loosened all of the delivery valve holders, and removed the diaphragm. With a bunch of spray lube, and a rawhide mallet I got the rack moving very smoothly.

Had all of the delivery valves freed up, and what I thought clean. Put it back together, tightened the holders back down. And the rack jammed again. While leaking down through the little springs inside the cover...

Clearly it wasn't clean enough.

So, how does one disassemble these pumps? -As in to take the valves and rack out? Doesn't really matter if it should come apart. It's gonna happen...

I already popped a known working pump on it. Still haven't got it running though..

The thing with the diaphragm is most likely the vacuum shutoff. What year is your vehicle?

The Delivery Valve Holders have a specific torque and it is not a lot. Over tightening it can damage the aluminum housing.

If you pulled out the delivery valve assembly which is 2 pieces mated together sometimes the barrel part of the Element (also a 2 piece mated assembly) comes up and out of the alignment slot (there is a pin in the housing that goes into a slot on the element barrel).
To tell if that is the issue you run down the delivery valve holder by hand and you compare the height of it to the others. If it is obviously higher you may have pulled the Barrel out of alignment.

I am presuming you have the special splined socket to use on the delivery valve holder.

__________________
84 300D, 82 Volvo 244Gl Diesel

There is a picture in post number 3 of a fuel injection pump with the cover off. It is OK to remove the cover but don't touch the squares blocks on what is the rack. If you move those you need to put the Fuel Injection Pump on a test stand to re-calibrate it.

ww.peachparts.com/shopforum/diesel-discussion/330728-603-injection-pump-failure.html

Assuming the rack is stuck because the element plungers are stuck. You can simply one at a time remove the Delivery Valve Holder and spring and the small valve on the delivery valve holder spray in some liquid penetrating oil (nothing with graphite) then you take a brass 1/8" brazing rod and round the ends of it with a file or what ever and about 3 inches long.

You stick the rod down into the hole in the delivery valve and get something light weight to tap on the top of the rod with. If the plunger does not go down like that rotate the Fuel Injection Pump from the drive end and do the tapping and rotating to see if you can free the plunger up.

When one is free re-assemble it. Look in the treads to find threads on changing the delivery valve seals and that will give details on what you are supposed to do concerning the delivery valves and holders.

See post 4. http://www.peachparts.com/shopforum/diesel-discussion/360250-220d-injection-pump.html

__________________
84 300D, 82 Volvo 244Gl Diesel

Its from a 180d engine around 1956. The diaphragm is the shut off, and how it senses throttle. No direct connection, other than vacuum to the pedal. It doesn't have a splined socket, just a normal hex. Those flat barrels did come out, I didn't see any type of pin to hold them in a certain place.

This is super antique diesel stuff. I freed everything up, and clean. Then I started to snug up everything by hand, and the rack jammed. When it jams, the valve springs inside don't reach the large barrels that ride the wee crankshaft.

That is why there is a need for the Year, model and even what Chassis is helpful post a thread. I was thinking it was from a later year.

The thing with the diaphragm on yours is the Governor which operates on vacuum.low pressure. With no vacuum you would get a lot of fuel for starting and with vacuum the rack will be moved to the run position.

Note I have not seen one of those pumps since about 1980 when I quite working for a Fuel Injection Shop where they came occasional to be rebuilt.

On yours remove the side cover and look inside and slowly rotate the front drive end of the Fuel Injection Pump and watch and see if you see the springs compressing and decompressing. This seems to be what you described.

The large barrels are Tappets and they have Rollers that ride on the Camshaft inside of the Fuel Injection Pump. You need to put Oil into to it. They used to recommend 40 wt Oil back in the 1980's. The excess Oil will leak out of #17 of the black and white picture.

Typically what happens is when a Plunger sticks it sticks upwards and the spring will be compressed on that one and won't decompress . One stuck plunger can keep the rack from moving. Dried Fuel and rust can keep them struck up. (Or does it look lie it is the Tappets that are stuck.)

If it is not the Tappets that are stuck this is where the 1/8 inch 3 inch long brass rod comes in. On the one with the compressed springs. You unscrew the delivery valve holder and remove the spring and the small central valve and spray in the penetrating oil and do the tapping to try to free the plunger as I described. If after a tap there is no movement turn the drive end of the camshaft and try again. It won't move till the camshaft lobe is positioned the lowest point and you cannot see that from the outside so it is trial and error.

__________________
84 300D, 82 Volvo 244Gl Diesel

The members on this part of the forum know more about the earlier models.

https://www.peachparts.com/shopforum/vintage-mercedes-forum/

__________________
84 300D, 82 Volvo 244Gl Diesel

Hey 300d 4 ME,

FWIW, this pump is a predecessor of the pneumatically governed PES4M injection pump that was used on OM621, OM615, and earlier OM616 engines. I'm pretty familiar with the later pump, and I see similarities between it and the one you're working on.

Part #16 in the diagram above, labeled "verstellhebel", or "adjusting lever", assuming its function is the same as it is on the later pump, is used to set the pump to stop, run, and maybe start positions. In the stop position the lever pulls the rack back, preventing fuel delivery. I'm wondering if the lever on your pump is stuck in the stop position, or maybe not engaging other parts in the pump properly upon assembly. This might explain why the rack moves freely until you put the pump back together.

Is that lever free to move? Or is it bound up? On the later pump the lever defaults to the run position when not connected to the control cable.

__________________
- Greg -
1973 220D, The Prodigal Benz
1974 240D

So the lever moves freely by it self. When the rack jams up, so does this. I had that diaphragm, and round rear cover for it off. All that lever does is act against the rack with spring pressure. Its totally fine.

Those lifters that ride the cam move freely. This all started when I noticed no fuel was coming out the injector lines. Took of that inspection cover, none of the lifters could touch the springs inside. They all keep jamming.

I was comparing this to a known working pump. After cleaning, and wacking the rack with a leather mallet. I got it feeling fine. Once I started to snug up the spring holders/ injector line threaded bodys on top. it started to bind again.

I'll try that brass rod trick. I'm also gonna soak it in acetone.

When I first looked at it, the rack was jammed in the full throttle position. Now I know the car was in a wreck, but I wouldn't think this is any of my issues. Just really gummy old fuel, and neglect.

You see, I was trying to rush this. Just swaped the engine into a w136- 170d. Have less than a week to make it 100 miles to a show. Finally decided to back off on this crippled Benz, and take a much more practical car.

"Trabant"

Several our members have a fascination with acetone but acetone has no lubrication qualities. Penetrating oil and even something like WD-40 would be a better choice but your choice.

__________________
84 300D, 82 Volvo 244Gl Diesel

Your very right.

In my case since the fuel was super sticky, and varnishy. Acetone cuts it nicely. Then comes the wd40- or light oils.

So after a good diesel, and acetone soak. I tried using some solid copper wire, and tapped down the element bores. Got one kinda free, the rest wouldn't budge.

I then decided to fully disassemble the pump. Really glad I did. The rear cam bearing is shot, some of the rollers looked destroyed. Thankfully the cam is perfect. I'll attempt to machine some new rollers.

Got the elements out, have them all soaking in a jar full of acetone. One came apart.

I know this will need to be adjusted when put back together. I have plans to hook it up to my metal lathe, and adjust it that way. Not all that scientific. Just involves some fluid measuring.

The Rollers, Roller Bushings and pins used to be reasonably priced.

__________________
84 300D, 82 Volvo 244Gl Diesel

You have pump PES4A, correct?

I dug around a little and found reference to test specs for a PES4A in this document, page 21:

http://www.kisandost.com/KisanMitraWeb/MarketBulletinView?moduleType=SubjectPartFile&FileName=109

The numbers for that "tractor" engine might not be the same, but could get you in the ballpark.

__________________
- Greg -
1973 220D, The Prodigal Benz
1974 240D