Quick question - the dreaded delivery valve holder leak - Bosch K-type injector pump

JohnDB · Nov 6, 2018

No. 4 holder is weeping (has been for months if not years - previous owner mentioned it), and I suspect no. 3 is just starting to as well - see photo. From the numerous threads on the subject I've decided to fix it myself (it's been wonderful reading the contributions of people on this forum and elsewhere over the years. You guys are awsome).

There seem to be only 2 options to fix the leak: (a) get the injector lines off and crack open each delivery valve holder and then re-torque or (b) pull all the lines off, pull all the holders and replace all the gaskets.

My questions are:
1. How successful is (a) above, usually. Should I bypass it and go straight to (b)? The attraction of (a) is less disturbance, but if it doesn't work I've got to do (b) which is more distubance of the fuel system because I've had to pull the lines of twice. I'm paranoid about dirt getting into the system (have been ever since seeing a video by Cummins about the damage dirt does).

2. On this pump, what is the "Gasket, deliv. valve" made of? Part number 15221-51240. The options seem to be copper ring, or rubber O-ring? Can someone confirm the material please?

Thanks in advance for your advice.

Sorry about the parts diagrams being so small - not sure how to fix it.

thepumpguysc · Nov 6, 2018

Just RE-TORQUE them.. they aren't very tight when they're new for some reason??
Remove the lines, u better have an appropriate sized wrench handy for the holder, cuz it'll probably turn too..
RE-TORQUE the holder to 30-35 FT LBS.. & retighten the lines.. The lines themselves don't have to be SUPER tight or you'll overcome the torque u put on the holder..
Chances are 80% or better, it'll fix the weep.. Good luck..
OH>> & DONT JUST TIGHTEN THEM>>TORQUE THEM..

JohnDB · Nov 6, 2018

Thanks, I need to suss out a socket that will fit the holders. Do you know what the gasket material is?

D2Cat · Nov 6, 2018

Look at part #1, the delivery valve holder. There is an o-ring under the lip on it. That is what you need to replace to stop the fuel leak if torquing the nut doesn't stop it. If you remove the holder don't fiddle with anything under there. it's a spring and a check valve that has to be in the correct orientation!

North Idaho Wolfman · Nov 6, 2018

Sorry on that model pump there is no O-ring on the delivery holder (One picture you posted is generic and does show O-ring).
Yes you can try just torquing them down, And I would recommend that too, but in my experience not very successful with that style of seal.

Now in regards to you being wary of working on it due to dirt/debri contamination, you're very smart to be with this style of pump.
The thing to note, there is nothing to stop dirt/moisture/debri from getting under and around the threads of the delivery valve and so when you remove the delivery valve all of that can fall directly into the pump section.
I almost always recommend that you remove the entire pump to do this type of reseal, but that has it's issues too.

Now in the real world here is a safe way to do it:

Use brake parts cleaner to wash off any loose material, remove all the injector lines so they are out of the way, loosen each delivery valve holder about a turn, then using the straw on the brake parts cleaner spray under the delivery valve gap washing out any material in there, I also use an air gun to blast everything away.
Then one at a time pull the delivery valve holder, remove the spring, then using small needle nose remove the seal, replace all parts and torque down the delivery valve holder to 28.9 to 32.5 ft lbs.
repeate till all done.
With the throttle set to high, crank in intervals as to not overheat the starter, and burp the injection pump, then install injector lines and bleed them same way and then tighten, start, run, enjoy.

The seal in question on this pump is a semi soft Copper seal/ Gasket.
Seal:
OLD P/N 15221-51240
NEW P/N 70000-65197

Still available in the states, if it turns out you need them and can't get them locally give a shout, and I'll help.

JohnDB · Nov 6, 2018

Thanks people, this is exactly the sort of info. I was looking for. I'll try the tightening route, then if that doesn't work will replace the copper gasket. Good point about potential for dirt to fall in when removing the holder, I guess same could apply to paint flakes - looks like that whole area was painted at the same time, so there must be paint in the gap where the holder meets the pump body.

If tightening doesn't work and I go to step (b), after I clean around the delivery valve holder first like NIW says, should I then put a smear of grease around the base of the holder, then unscrew the holder, the idea being that the grease will stop any paint flakes that get dislodged falling into the pump? (Then clean the grease off before doing the next steps.)

North Idaho Wolfman · Nov 6, 2018

JohnDB said:
should I then put a smear of grease around the base of the holder, then unscrew the holder, the idea being that the grease will stop any paint flakes that get dislodged falling into the pump? (Then clean the grease off before doing the next steps.)

I wouldn't, (makes it really tough to work on) just clean it good before you start, loosen all of the holders a little, then clean again, that will remove any paint and debri.
One other trick is to have a syringe full of diesel and flood each of the pumps cavities right before you reinstall the holders, this will flush out anything that fell in.

thepumpguysc · Nov 6, 2018

Your playin w/ fire loosening the holders.. just retorque them..

JohnDB · Nov 6, 2018

I'll get in touch with you Wolfman if I run into problems with the gasket. I see why the grease isn't a good idea, I didn't read your cleaning suggestion first time carefully enough - yes extra flushing required.

Thepumpguysc I'll try tightening the holders, not loosening them, to start with. Usually I've got time on my side so it's worth taking it one step at a time. Yes I could get burned, but overall at this stage of my life I feel like it's been worth it

Warnings are heeded - I'll take extra care.

Thanks guys, will post an update, probably take me a week for stage one, need to get me a thin wall socket.

JohnDB · Dec 22, 2018

Finally got this done. Funny thing - torqued the leaking delivery valve holders - the leak stopped on one, but got a lot worse on the other. And on one that hadn't been leaking, started leaking (just experimenting...).

Got new copper washers ("Gasket, deliv valve 15221-51240” approx 0.48mm thick 11.64mm OD 9.10mm ID. The injection pump service shop also said I'd need rubber O rings - I almost turned them down because the parts manuals didn't show any rubber O rings but I took them anyway (14.98 or 15mm ID x 2.38 or 2.4 mm thick). Turned out that the delivery valve holders did have O rings under the head. Fitted it all up, trying the keep the parts and surroundings surgically clean. SUCCESS! No sign of leaks

The old O rings had developed a compression set, and every one of the copper gaskets had signs of erosion, but only on the lower face, like tiny crevices radiating out from the ID.

So, job done, my thanks to Wolfman, D2Cat, the pumpguySC for your help

JohnDB · Jun 10, 2020

A quick follow-up for those that are curious - finally got a USB-connected microscope going. The 11mm diameter copper gaskets that I referred to in my last post above look like this:

Left gasket is showing the upper (DV holder) side, the right gasket shows the face that's against the lapped topside of the delivery valve body. No wonder it leaked. Damage around the inside edge may be due to cavitation erosion (?), which has allowed the diesel to exit and make its way up past the O ring to the top of the pump.

For comparison here's a new gasket on top of some old ones:

Again, many thanks to members who contributed.

makowa · Nov 25, 2020

JohnDB said:
A quick follow-up for those that are curious - finally got a USB-connected microscope going. The 11mm diameter copper gaskets that I referred to in my last post above look like this:

View attachment 44115

Left gasket is showing the upper (DV holder) side, the right gasket shows the face that's against the lapped topside of the delivery valve body. No wonder it leaked. Damage around the inside edge may be due to cavitation erosion (?), which has allowed the diesel to exit and make its way up past the O ring to the top of the pump.

For comparison here's a new gasket on top of some old ones:
View attachment 44117
Again, many thanks to members who contributed.

hi, really good job with

JohnDB said:
A quick follow-up for those that are curious - finally got a USB-connected microscope going. The 11mm diameter copper gaskets that I referred to in my last post above look like this:

View attachment 44115

Left gasket is showing the upper (DV holder) side, the right gasket shows the face that's against the lapped topside of the delivery valve body. No wonder it leaked. Damage around the inside edge may be due to cavitation erosion (?), which has allowed the diesel to exit and make its way up past the O ring to the top of the pump.

For comparison here's a new gasket on top of some old ones:
View attachment 44117
Again, many thanks to members who contributed.

hi,
congrats with job well done. I have the same problem with my b2150hst and I wonder if I can do it by my self too. I'm worried tho about what d2cat said about valve and spring orientation, that it need to be exact. how it was in your case? how I can make sure to not make it wrong (keep the correct orientation, is it any way obvious)?
again congratulations for your success and thank you for your detailed description
Chris

JohnDB · Nov 25, 2020

makowa said:
... I'm worried tho about what d2cat said about valve and spring orientation, that it need to be exact. how it was in your case? how I can make sure to not make it wrong (keep the correct orientation, is it any way obvious)?
...
Chris

Hi Chris - the correct valve and spring orientation that the spring (2) should be above the valve (3) as shown in the image with the yellow arrow, not the other way around and it's pretty obvious when you remove the delivery valve holder.

I know you didn't ask about it, but the big deal is, as others have said, make sure everything is scrupulously clean - above, below and around the pump, ensure that the outsides of the fuel lines are clean (I don't have access to a steam cleaner, so I spray on kerosene and wash it off with sprayed water, followed up with drying the top of the pump and surrounds with compressed air before removing fuel lines and delivery valve holders, so that no dust or dirt gets anywhere near the internals of pump. Do it in a dust-free, grit free, well-lit place, have clean hands, clean gloves, clean tools, and clean lint-free rags

Take your time. Prep is essential. That's what I try to achieve anyway. Hope this helps.

makowa · Nov 25, 2020

JohnDB said:
Hi Chris - the correct valve and spring orientation that the spring (2) should be above the valve (3) as shown in the image with the yellow arrow, not the other way around and it's pretty obvious when you remove the delivery valve holder.

I know you didn't ask about it, but the big deal is, as others have said, make sure everything is scrupulously clean - above, below and around the pump, ensure that the outsides of the fuel lines are clean (I don't have access to a steam cleaner, so I spray on kerosene and wash it off with sprayed water, followed up with drying the top of the pump and surrounds with compressed air before removing fuel lines and delivery valve holders, so that no dust or dirt gets anywhere near the internals of pump. Do it in a dust-free, grit free, well-lit place, have clean hands, clean gloves, clean tools, and clean lint-free rags Take your time. Prep is essential. That's what I try to achieve anyway. Hope this helps.

Thank you JohnDB very much for all your advise, I'll make sure is as clean as it should be.
Chris

Mopig · Nov 12, 2024

Hi guys,

As the PO mentioned above the amount of threads on this issue and the helpfulness makes for much calmer reading so the nerves arent up!
I also have this issue, also down here in NZ but on a L2850DT-GST 4cylinder.
I had some fuel delivery problems after not long just purchasing this machine and now we have a new fuel bowl, filter and free flowing fuel supply and after bleeding it up, I now also have two leaking seals from under like the post here.
I 'may' have let the bottom delivery holder move whilst cracking it, I wasnt expecting the tube to be so bloody tight. Anyway, trying to nip them back down has just made it worse. So looks like this job is next to do, but at least she is running now in the mean time.

My main question is, looks like I need to get the inlet manifold off too, so I need to order the gasket for that.
There's not alot of room for the socket in between each port. I need to find a skinny socket! or you good folk just use crows foot?

North Idaho Wolfman · Nov 12, 2024

Mopig said:
Hi guys,

As the PO mentioned above the amount of threads on this issue and the helpfulness makes for much calmer reading so the nerves arent up!
I also have this issue, also down here in NZ but on a L2850DT-GST 4cylinder.
I had some fuel delivery problems after not long just purchasing this machine and now we have a new fuel bowl, filter and free flowing fuel supply and after bleeding it up, I now also have two leaking seals from under like the post here.
I 'may' have let the bottom delivery holder move whilst cracking it, I wasnt expecting the tube to be so bloody tight. Anyway, trying to nip them back down has just made it worse. So looks like this job is next to do, but at least she is running now in the mean time.

My main question is, looks like I need to get the inlet manifold off too, so I need to order the gasket for that.
There's not alot of room for the socket in between each port. I need to find a skinny socket! or you good folk just use crows foot?

Pull the intake and use a deep socket.

Mopig · Nov 12, 2024

thank you @North Idaho Wolfman you are a legend here.
all parts ordered today so hopefully have what's required tomorrow and a new bleed valve since the knobs broken off..
Also, the bleed valve, is it normally run all the way out ( anticlockwise ) or all the way in?? without seeing how it operates interally i guessed all the way in but only runs with it turned all the way anticlockwise.

North Idaho Wolfman · Nov 12, 2024

Mopig said:
thank you @North Idaho Wolfman you are a legend here.
all parts ordered today so hopefully have what's required tomorrow and a new bleed valve since the knobs broken off..
Also, the bleed valve, is it normally run all the way out ( anticlockwise ) or all the way in?? without seeing how it operates interally i guessed all the way in but only runs with it turned all the way anticlockwise.

Closed / run is clockwise.
Bleed is anticlockwise.

Mopig · Nov 12, 2024

Mhm, now i need to check which way it IS turned, maybe i'm wrong ( hopefully ) but just remember thinking that's weird... Either way, its running so I got something right LOL

North Idaho Wolfman · Nov 12, 2024

Mopig said:
Mhm, now i need to check which way it IS turned, maybe i'm wrong ( hopefully ) but just remember thinking that's weird... Either way, its running so I got something right LOL

Most models will run in either position.

With it open it just recycles fuel over and over again.

Quick question - the dreaded delivery valve holder leak - Bosch K-type injector pump

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