Low Pressure Supply Line leaking

["Mad Max"]

So we're driving TJ's rig and it looks like the low pressure supply line to the injection pump is leaking pretty good. Question is, what makes the seal for it? Rubber O-rings, brass washers? Compression fitting like a brake line? Are there any little springs inside that wear out, or is it just a simple ole- fitting that gets old and cracks loose when it gets cold? It's been pretty cold lately out here in Colorado.

Ideas? Thanks all -

- Sam

 

[Greenleaf]

Where is it leaking?? @ the pump's connection next to the throttle lever?? Dat's ah commpression fitting. I'm looking down inside of that fitting now and don't see where an O ring would be. i don't recall the line wrench size I used. 14mm?



-S

 

["Mad Max"]

good question and good point -

It's leaking on the pump side right in front of the injection pump lever. We're thinking it was cranked too tight earlier and the weather just opened up a crack. Going over to troubleshoot now.



A cool point here: I posted this about half hour ago and was hoping for a response by the end of the shower and breakfast - you guys rock in here, absolutely 2nd to none! Now we know what to look for - service manual has very little info on the line which leads me to believe it's a simple fix.



Thanks Scott - I was hoping it was a compression fitting. It's on the low pressure side so if we need to fab up a new line that shopuld be okay with local parts store fuel line... I hope.

- S

 

[dpuckett]

The line you are referring to was ~$25 from Cummins Gateway this past summer for Mom's pickup. Goes from behind the pump, around the pass, side, and into the pump. Kinda hard to get to, but can be done in 30min or less. I'll see if I cant find the P/N this afternoon. And last I knew, the KW dealer in the Springs was a Cummins dealer/ distributor, or something to that effect. Weather has been in the high 70's this weekend here. I miss the praire



Daniel

 

["Mad Max"]

...not the low pressure fitting...

Okay, so we discovered it isn't the supply line, or the KSB solenoid vent line - it appears to be a brass 9/16 bolt that threads into the pump (from the front side of the pump) directly below and between where the supply line and vent line go into the top of the pump. It was only possible to get at by slightly bending the vent line towards the back and then the wrench could get at it. Attempted to tighten - no luck. Tried to loosen and retighten, but couldnt really tell if it was moving at all or if wrench was slipping on bolt head. It looks to be impossible to remove the bolt and replace whatever washer or o-ring (we hope) is below it without removing the pump. If so, how big a deal is it to remove the pump and replace that part? Hopefully it doesn't mean the pump is screwed.



Can any of y'all tell us if this is actually a bolt and what may be leaking from below the bolt head that allows a steady leak (2 drips every 10 seconds)? It doesn't leak while the engine is off. Does this indicate a pump housing failure or has someone seen this and fixed that?



Thanks all,

- Sam

 

[Greenleaf]

I have no idea what this does. I'd have to look in my pump tech CD. With all the mods I have studied, this bolt isn't sumth'n mentioned.



It's esentially a bolt with an internal hex head (5mm hex key/Allen wrench) with a lock nut (14mm wrech) with a flat washer behind it. This washer seals the internal pump pressure from leaking. This washer may have the rubber O ring molded into it (?????) to assist sealing the fuel.



Again, no clue what this does. Turn it and find out But seroiusly, you'll have to pull the pump as you probably cannot remove the washer with pump on the engine. Perhaps pull the pump back some????? I'm looking @ the pump I'm building that is on the bench and that bolt is next to the pump mounting flange.



I'm pulling at straws here.



Scott

 

[HFletcher]

I believe that bolt accesses the end of the governor shaft. The gov shaft is sometimes drilled (longitudinally and transversely) and connects with a bore in the housing leading to the suction side of the supply pump. This is used in load dependent compensation. Hank

 

["Mad Max"]

Thanks Scott, Hank - really appreciate your quick responses. Now we have to figure out a way to keep it from leaking. I like the idea of not having to remove the pump completely but that's not the 'A' answer. Fuel is just draining out behind it, but intermittently. Yesterday no leaks, today they're back. Weird, but there it is.

Will post back as to how we fix the leak - hopefully without too much swearing... .



- S

 

["Mad Max"]

well we got the nut or nut/bolt loose, was able to rotate the washer a few times, but there must be a rubber o-ring inside that seals the bolt off... . and if there is a little rubber o-ring in there it seems the little bastage' is jacked up. We're so frustrated that a seemingly so small and tiny piece of whatever it is is so involved to fix (read remove the pump... . ).



Okay, so how involved is it to remove the pump anyway? We read the manual about it - lots of little steps, but how much work is it really?



- S

 

[cerberusiam]

If that seal is leaking the rest of the little buggers may close also. Might be time to pull the pump and replace the other trouble makers. I don't think its that bad a job to pull the pump but thats just me. Three things to remember -



Don't drop the key on the pump drive



Don't forget to lock the pump down after finding TDC.



Remove the oil pressure sending unit or you will be replacing it.





Other than that its a fairly easy mechanical job. Just save the brews for towards the end of the job.





Oh yeah, don't forget to unlock the pump when your done. Tends to negate all the careful work up to that point. :{

 

[HFletcher]

I think removing the pump is a major PITA and I've done it several times. In my opinion it's only easy if you first remove everything in front of the pump so you can view the pump gear/drive thru the core support (i. e. remove radiator, intercooler, fan). That is the only way I will do it nowadays - the hour spent there will save you many more hours wasted trying to reinstall the pump drive gear and key when you are blind, upsidedown, using a mirror and in a very uncomfortable position. It will also greatly reduce the possibility of dropping the key into the gear housing.



Before removing the pump I do not put engine on TDC. I simply rotate the engine until the keyway is about on top, then lock the shaft, and remove the pump. (If you put the engine on TDC the key is down as I recall, and more susceptible to falling into the gear housing. ) For what its worth, I no longer lock the pump before removal. It is my experience that when you reinstall the pump the keyway lines things up. I don't think it is possible to jump a tooth based on the limited range of motion allowed the pump during installation, but I haven't tried purposely rotating the shaft enough to determine this. It is probably wisest for you to simply lock the pump after rotating the keyway to about the top, then remove the pump. Hank

 

[DKasper]

Sam, pulling the pump is not awful, but it's not a lot of fun either. Shouldn't be any problem for someone of your ability!!

When I did mine, I did it like Hank said -- did not put the engine @TDC, but locked the pump as soon as it was pulled. If I remember, the steps in the manual are pretty close to what you have to do:

- pull the injection lines

- disconnect the fuel solenoid electrical lead

- Mark the position of the pump on the gearcase

- loosen the PS pump support and swing it out of the way(had to go underneath for that)

- remnove the oil fill neck

- pull the gear out of the case

- stuff a clean rag in the case so the key doesn't fall in while removing it!

- Remove all the bones in your right hand & forearm so you can contort enough to get that 3rd bolt behing the pump. :-laf



Took me about 2 hours the first time -- that's pretty slow, I think.



After I re-installed it, I got paranoid about the timing after hearing that it can be almost 20 degrees out of time before it becomes audibly noticeable. So I went down to the local diesel guru's shop and we timed it with a dial indicator -- it was right on.

Have fun! I want to see pics when you get your body work done!



Cheers,

Dave

 

[nascar mark]

Hey Sam,

That allen head screw with lock nut has a O-ring for a seal. You will have to remove the pump from the gear housing and re-re on the bench.

Before you back off the locknut, measure the allen screw protrution in relation to the pump as this is a set measurement for the governor shaft which supports the weights. Write down the measurement, lossen off the lock nut, turn out the allen head screw just far enough to pull the O-ring off and install new O-ring. Turn allen screw back in until its back to the original measurement and lock down the lock nut. Check measurement again. If measurement is right, your good to go.



As a side note, I've pulled a few of these ve pumps off in the past and find it easiest to pull the goods off the back of the pump, then the oil filler tube off the front gear case and remove the pump nut and lock washer so you can see the key way on the shaft. Rotate the engine by the alt nut so the key way is at 1:00 o'clock instead of having the engine at TDC and have a chance of the key falling out upon removel or install, plus it is easier to line up if your doing the job yourself. Now break the pump gear off the shaft and remove the pump. When the pump is removed, you can spin the pump shaft all you like if you didn't pin the pump as long as you put the shaft key way back in the same location as it was when you removed it.

The pump doesn't need to be pined unless you are anal and have to be axactly the same timing to the "mm" you were before. If so, pin the pump with the same method as above and you will be as close as TDC and pined pump.

 

["Mad Max"]

is an o-ring an o-ring...?

Mark,



For the o-ring, is that a 'typical/common' o-ring from local parts store (and just match one up), or a Bosch-only item? Is there a rebuild 'kit' for the parts involved or is an o-ring an o-ring? I'm thinking #2 is easier on rubber than gasoline? Good for cleaning parts too... .



Thanks for the info and replies fellas. We were figuring we'd have to pull the pump, and as neither of us have ever done it we're naturally a bit leary - not of the job but of missing some little piece of the puzzle that we wouldn't have normally noticed, ya know? Both TJ and I can tear a Holley or Carter 4bbl apart and reassemble in our sleep, so we appreciate the 'street knowledge' for the pump R/R. Books are fine, but savy is where it really counts.

Thanks again dudes - we'll probably tear it out Saturday.



Dave, me too!! It should be a really fun project. It's been in the 30's out here and I'm getting the natural gas plumbed to the heater this week, maybe the week after. Should keep the whole project at 70* all winter long - the only way to fly. I'm also thinking this little project of mine may take a bit longer that 9 months - I know myself pretty well and I know I'm going to take my time and make it purrrrfect, but won't know until it all comes apart. Ramcharger is first, then there's Christmas - so probably January will kick off the tear down. I think I'm going to need Kenworth badges by the time it's all done... . scheesh :-laf



- S

 

[nascar mark]

Sam,

This is not a time to cheap out.

Unless you like pulling injection pumps off of engines, get the proper O-ring from a Bosch shop and do it right. It shouldn't be more than $3-5.

 

["Mad Max"]

you bet - that's what I figured :-laf . Is there a good part number or do you have a contact at Bosch I can call?

Thanks Mark,

- S

 

[nascar mark]

Pull out the telephone book and look up your nearest Bosch pump shop and they will have a O-ring for you. I can get you one but shiping would be 3x what the O-ring is worth.

Now quit wasting time and pump out some of those intakes young man.

 

[Greenleaf]

drus (Hank)



I'd love to talk more on the topic of pump mods with ya, but you are unable to recieve PM's. I tried to answer your message to me but I can't send it



Scott aka Greenleaf

 

["Mad Max"]

Well, were a'gonna pull'a z pump and'a pull'it' apart and'a replace'a de partz. I don't imagine it's any worse than rebuilding a Thermoquad, but I won't say the same about a Holley or an AFB - they be easy. Ordered two pump kits from Bosch via local dealer in Denver - sounds like a standard rebuild kit, but has the gaskets, o-rings and apparantly the little bronze sleeve for the throttle lever that goes bad. (sheesh) Listen to me yap- I sound like I know what I'm talking about...

TJ and I are going to do the pump work up in Denver with a new friend that's going to show us how and not allow us to jack up anything too seriously. Should be fun - I ordered 2 kits, for that eventual time when my own pump goes sour.

- S

 

["Mad Max"]

Cool - Pump's out, no worries. Went pretty well - had to cut the low pressure supply line because the fitting edges were really jacked up - we'll just get a new one and call it good. Pump came out like a champ - had to make a short stubby custom gear puller - worked great and gave me a good excuse to modify tools.

Now it's off to the pump shop for a quick rebuild, and back in it goes. Kit from Bosch was $15 - pretty good I figure.

Cool - off to the haunted house - HAPPY HALLOWEEN!!

- Sam