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Oil Leak - MW Bosch - DT466C


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I have a 466C and IH chassis under a 1966 Merc F700 - if anyone is curious about the truck you check it out in the Proejcts section of this forum. Apparently it was the end of the day when I painted the bottom side of the injection pump - kind of embarrassing to post this picture!

The pump had a massive ball of dirt and oil on the bottom of it when I first bought it.  I figured it was that cheapy tin cover/pan on the bottom of the pump, since they are known to be problematic.  I replaced it - I think it may have been leaking too as the o-ring didn’t look too healthy on the old cover.

I have my project in the final stages and I am starting to use the truck.  It appears I still have a small drip coming back.  It looks be between the injection pump and the pump adapter plate.  I am still searching for a 466c service manual, and I haven’t had much luck on the internet either.  Note that open bolt hole is not leaking, for some reason the bolt was missing, and I plugged it with a bit of shop towel, and it’s stayed bone dry.

It looks like the pump has to come off. To confirm, am I correct that I am best off pulling the adapter plate and pump as one whole unit?  Does this allow the front drive gear stay attached to the pump? 

There is a plug on the side of the adapter plate with timing marks in it.  If I bump the engine over and get these marks lined up, I assume that will make re-install easier?  I don’t plan on turning the engine or pump while things are apart anyway.  

In terms of what’s leaking - what seals between the pump and the front adapter plate?  Is it part# 34 - it’s labelled as the “front bearing housing ring”.  That could mean a few different things I suppose...

(those parts diagrams are from an old IH MW Bosch pump manual available by a quick google search if anyone is looking)





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#34 is an O ring, IH part #670875C1, and is still available.  when you remove the pump, Align the marks up, and the note the reading on the front pulley(should be 24 degrees BTDC I think?)

   The adapter plate comes off with the pump.  Remove the round cover on the front of the engine that covers the pump gear.  I would suggest making some marks where the pump gear meshes with the idler gear.  Then continue with removing the pump/adapater plate removal.

   Once you get it out, you'll end up making more match marks on things in order to get the adapter plate removed and the O ring changed.  Reassemble everything, ensuring that the timing pointer is on its spot when the front pulley is on its spot as well.  At this point I always turn the engine over by hand 2 turns (in the normal direction of rotation) and double check that the pointer still lines up when the front pulley is at its spot.  

  If you don't have a CaseIH dealer nearby, I've learned that my local International truck dealer can get many parts for these 466 engines and pumps.  I've even got parts from them when the CaseIH guy was telling me its discontinued.

  If you want a service manual contact peaceful creek manuals and tell them what youre looking for, I believe the Manual #is ISS-1522-1.

 For the basic stuff like seals and gaskets, you should be able to get the part numbers by going into the CaseIH parts site and pick a 466C engine.

   Someone else should confirm the 24 degrees timing to be sure, I know thats what a 466B with the Robert Bosch is set at, not sure if the 466C uses the same setting??

  Hope that helps a little?





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This is great info, thank you!  

Yes I have been told the 5488’s etc with the MW pump are timed at 24deg from past questions on this forum.  My engine tag says 18, but it seems to be set at 24deg, so go figure.

Should I also replace part number 32 if it’s in bad shape?  Or does it not matter if it leaks?  (I can’t tell if the o-ring #34 seals around the pump bearing housing #33 , or just the outer face of it).

I am probably asking questions that are hard to answer without tearing into things, I just want to get my parts lined-up best I can.

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#32 is gasket 1806274C1, which is discontinued by CaseIH.  You could check with a Ih truck place, a pump shop or make your own.(use the same thickness material).

       If it was mine I’d change the gasket too, unless it’s obvious that #34 is hard/brittle and is the culprit.

      18degrees timing was normally for the American Bosch rotary pumps, it’s possible this thing had one of those on originally.  If that’s the case the injection lines should’ve been changed as well and wouldn’t have looked original.  The injectors are also different between the two pumps.

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It was the valve cover that had that timing on it, so who knows.  At a truck that age, the history gets murky.  I am 100% it is an original Bosch MW engine though - injector lines are OE, truck is and 86 and hasn’t seemed too tampered with, and 200000miles, etc.  

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