multifuel fuel pump hydraulic head removel

hello i need to change my hydraulic head on my fuel, pump can anyone tell me how to do it thanks

The manual gives a pretty detailed procedure, and IIRC it is downloadable from this site. If its not, drop me a note and I'll email you scans of the pertinent pages.

Nice looking M55A2, BTW.

Regards,
David Doyle

oh..and

POST a pic of your other things militare!

RE: oh..and

For your LDS465 engine, basically:

1) Remove the steel lines to the injectors
2) Remove the cover for the fuel cut-off mechanism
3) Remove the fuel cut-off lever (be careful with the "tooth" at the end which is loose)
4) Turn engine over manually until a scored gear tooth (may be marked in red) is lined up with a pointer visible when the fuel cut-off lever is out of the way.
5) Remove all fuel line connections and 4 ea nuts clamping the hydraulic head.
6) Pull hydraulic head straight up, you may have to tap it lightly. Reverse procedure for installation.

I just finished working on mine and it's pretty fresh in my mind.

TM 9-2910-226-34

Ok so I'm looking to remove the HH and I'm searching for info. Yes I know, searching first. Odd. Anyways. I have a pump out on the bench to practice on. I have read the tm, a lot of the ss posts, and heard from some people. I have the shutdown removed, the timing marks lined up, red tooth, advance mark also. the four nuts removed and the collars removed. The head lifts about 1/16 inch and stops dead. It will rotate some. I have a c code pump so it does not have the filter to remove. Do I need a bigger hammer or did I miss something? This post seemed the most like my problem so I added to it. Thanks, Andrew

Problem solved. Thanks Gimpyrobb! Don't forget the shutdown rod....... Even if the safety wire scares you away, it's gotta go!

do not line up the timing marks. line up the red tooth and pointer. they are different.

tom

Remove the fuel shut off cover on the side of the pump below the hydraulic head, and cut the safety wire on the fuel control shaft retaining clamp. Remove the 2 screws, the clamp, and then unhook the governor rod from the fuel control shaft by carefully removing the small clip. Pull the fuel control shaft out and make sure you retrieve the small key/pin from the fuel control plate if it didn't come out with the fuel control shaft. You may find a small mirror helpful to do this and the next step. I used a white automotive paint touch-up tube with a small brush to mark the gear tooth (or groove if in between teeth) that is in line with the fixed witness pointer just above the gear. This is for reference for when you reassemble, so you don't have to roll the engine over to line up all the timing marks. If changing the HH, just mark the new head's gear like the old one you are replacing. Count the number of teeth from the factory mark to the painted alignment mark you just did prior to pulling the old head, and put a paint mark on the new head's gear tooth in the same relationship to the factory alignment mark as on the old HH gear. Of course you still have to remove the injector lines from the top of the hydraulic head and the fuel lines from the front and rear of the head as well. Remove the 4 retaining nuts and clamping spacers and the head pulls straight out.

maxspeed250, your info is very wrong and may cause someone to damage their pump. you MUST line up the scribed (red) gear tooth with the pointer for internal components to clear when lifting the head. any other position will do damage. perhaps you or someone else before you damaged your pump and it came apart, but this is NOT the way to do it. it should be noted that replacing the head has nothing to do with 'timing' marks in the usual sense. the scribed gear is only to locate the notch in the drive gear shield. the red gear has nothing to do with actual injection pump timing.

tom

So Tom, you are saying that the marks under window with 4 bolts is the important one, not the red gear on the HH itself? I am asking because I have found some HH that would not come out when lined up at the red tooth.

chris, no this is where some people get confused. the mark under the small cover with 4 bolts is a timing mark to time the entire pump with the engine. the red tooth with line scribed on it is only for servicing the HH. when the red tooth is lined up the HH should lift out easily. now if someone put it back togeather incorrectly that would change everything, but i doubt it would run.

tom

Cool, thank you.

m-35tom said:

chris, no this is where some people get confused. the mark under the small cover with 4 bolts is a timing mark to time the entire pump with the engine. the red tooth with line scribed on it is only for servicing the HH. when the red tooth is lined up the HH should lift out easily. now if someone put it back togeather incorrectly that would change everything, but i doubt it would run.

tom

Click to expand...

If someone did put it back wrong could it not be advanced or retarded some. I still think it is better to line up everything then check to see who what when and where?

So you could line up balancer line, pointer line and the HH should be off to the rear by one tooth. Timming is correct. Then spin motor backwards till HH head scribe red line and pointer are aline, change head and you should be good right.???? Sorry I edit the part where you would advance the motor to read spin motor backwards to line up HHhead.

Floridianson said:

If someone did put it back wrong could it not be advanced or retarded some. I still think it is better to line up everything then check to see who what when and where?

So you could line up balancer line, pointer line and the HH should be off to the rear by one tooth. Timming is correct. Then advance motor till HH head scribe and pointer are aline, change head and you should be good right.????

Click to expand...

well yes that is right but that's the point! not everything lines up at the same time!

checking the injection timing is one thing, and may be done to confirm the settings, but servicing the HH is another matter entirely and is not really related to the overall timing as nothing changes when you take it apart and then put it back togeather.

tom

HH removal option

m-35tom said:

maxspeed250, your info is very wrong and may cause someone to damage their pump. you MUST line up the scribed (red) gear tooth with the pointer for internal components to clear when lifting the head. any other position will do damage. perhaps you or someone else before you damaged your pump and it came apart, but this is NOT the way to do it. it should be noted that replacing the head has nothing to do with 'timing' marks in the usual sense. the scribed gear is only to locate the notch in the drive gear shield. the red gear has nothing to do with actual injection pump timing.

tom

Click to expand...

Not to be disrespectful Tom, but I think it is YOUR information that is incorrect and confusing. The hydraulic head has basically 2 functions, one is provide a high pressure, metered volume of fuel 3 times per crankshaft revolution, and the second is to distribute it to the correct cylinder at the correct time - to initiate and sustain a combustion event. I won't proclaim myself to be an injector pump "expert", but I have worked with far more complex mechanical devices during decades long employment as a machine tool tech, and also as an aerospace instrument maker and integrator. I did read TM 9-2910-226-34 to understand the function of the hydraulic head and injector pump drive components, and their relationship to the timing marks on the crank balancer, and pump shaft. Of course, you can turn the engine over until you are at TDC on #1 cylinder, verify the balancer, pump shaft, and hydraulic head timing marks are all lined up, but assuming the engine was a runner before HH failure / removal, you can remove and install the HH by just painting a new alignment mark on the HH drive gear and reinstalling it to the same timing mark - AS LONG AS YOU DO NOT ROTATE THE ENGINE WITH THE HYDRAULIC HEAD REMOVED.
Regardless of crankshaft or injector pump rotational position, when all fuel lines, governer rod, fuel control shaft, and the 4 hold down nuts and collars have been removed - the head will pull straight out off the pump body. Sometimes they are a little sticky, but it WILL come out. And my procedure works fine when the HH is being removed and replaced -again as long as the engine is not turned while the HH is removed. It is the way I swapped hydraulic heads on my M35A2 that had a seized pump head plunger, and I assure you that it runs VERY WELL!

maxspeed250 said:

Regardless of crankshaft or injector pump rotational position, when all fuel lines, governer rod, fuel control shaft, and the 4 hold down nuts and collars have been removed - the head will pull straight out off the pump body. Sometimes they are a little sticky, but it WILL come out. And my procedure works fine when the HH is being removed and replaced -again as long as the engine is not turned while the HH is removed. It is the way I swapped hydraulic heads on my M35A2 that had a seized pump head plunger, and I assure you that it runs VERY WELL!

Click to expand...

I disagree with your statement here. The gear that drives the hydraulic head has a cap/washer on it. That washer has an arc cut out of it. The HH will ONLY come out when the arc is facing the HH gear.

you are right on chris. maxspeed250, however smart he thinks he is, is completely wrong. the tooth with the line is to ensure the arc is in the propper position. any other spot will damage the pump.

tom

I have seen some HH that the red tooth had to be one tooth more from the indicator to come off, truck ran good before and after the swap, but it does seem some are different.

Here are a couple cruddy pics I had.

In the first 2 pictures, you can clearly see the thin metal "plate" on top of the gear that drives the HH. It has a half round cutout in it that will only allow the HH to lift out in one position. To properly position the HH for removal, you need to look inside the shutoff rod cover, to index the "cut out" in the correct position(as indicated by the painted tooth and pointer).

Technically, you could index that "cutout" to the correct position, to remove the HH, with the mark on the harmonic balancer, or the line and pointer in the small window on top of the Governor. Not by using the pointers and lines , lined up.

The TM tells you how to use the painted mark on the HH gear(viewed in the shutoff rod area).

The above text in red, may confuse many people. Simply ignore it if you don't understand what I am saying.

In picture 3 above, and the picture below, the "cutout" is lined up to allow access to remove the HH, and the line stamped in the disk is even with the window opening(shown in the picture below with a green arrow and line), not the pointer. That is how you could use that opening and indicators to line up for HH removal.


I have not referenced where the harmonic balancer marks are, when the cutout is lined up. But you could use that also, or another "timed" item on the engine.... Again, this is not how the TM says to do it and it is not the best option, but it is possible if you know what your looking at.