Caterpillar D6D Fuel pump

Hi Richard,
the crud gets into the normally dry detent and Idle adjust screw housing when that Chinese bloke Sum Wun steals or forgets to put back the Injection Pump Timing Pin/bolt, P/No--4N6430, back in place into the protrusion you see at the rear of the outer cover you have removed.
When the crud and water gets in it causes rust pits in the springs and they fail/break--quite common due to the above reasons. Not all engine applications had the pin/bolt, I seem to recall.

There is an update/repair for the main rear Governor Housing spindle bushing bore--they did not have a bushing originally-- and we had a jig and reamer to fit them at The Dealer, once done they can easily be replaced.
I think the shaft movement, when the alloy housing wears, is too much for the seal lip to cope with--along with rusting at the lip/shaft working area.

You now cannot just simply re-fit the spindle as there are Governor actuating parts inside the Main Gov. Hsg. that will have dropped into said housing and can only be re-instated with the housing on the bench.

The inside of the injection pump and rear gov. housing are full of fuel at around 30 PSI when the unit is operating.

Alas, I only have a Parts Book for a D6C and not a D6D, that shows the Sleeve Metering Pump--I cannot recall if there are any major differences in the two pumps other than maybe either/or both, if at all, the Torque Spring Group and Governor Spring.
I guess if you do not have a Parts Book I can scan what I have if it may help at least give you an idea what is inside--seals and gaskets etc. should be same between the two units.
Cheers,
Eddie B.

[quote="edb"]Hi Richard,
the crud gets into the normally dry detent and Idle adjust screw housing when that Chinese bloke Sum Wun steals or forgets to put back the Injection Pump Timing Pin/bolt, P/No--4N6430, back in place into the protrusion you see at the rear of the outer cover you have removed.
When the crud and water gets in it causes rust pits in the springs and they fail/break--quite common due to the above reasons. Not all engine applications had the pin/bolt, I seem to recall.

There is an update/repair for the main rear Governor Housing spindle bushing bore--they did not have a bushing originally-- and we had a jig and reamer to fit them at The Dealer, once done they can easily be replaced.
I think the shaft movement, when the alloy housing wears, is too much for the seal lip to cope with--along with rusting at the lip/shaft working area.

You now cannot just simply re-fit the spindle as there are Governor actuating parts inside the Main Gov. Hsg. that will have dropped into said housing and can only be re-instated with the housing on the bench.

The inside of the injection pump and rear gov. housing are full of fuel at around 30 PSI when the unit is operating.

Alas, I only have a Parts Book for a D6C and not a D6D, that shows the Sleeve Metering Pump--I cannot recall if there are any major differences in the two pumps other than maybe either/or both, if at all, the Torque Spring Group and Governor Spring.
I guess if you do not have a Parts Book I can scan what I have if it may help at least give you an idea what is inside--seals and gaskets etc. should be same between the two units.
Cheers,
Eddie B.[/quote]

Hi Eddie,

Thankyou for the reply.

The customer ordered the spindle seal and gasket and I arrived to fit it........but we were both surprised what greeted us on the other side.
I do have a parts book but not with me at the moment and not on the job site where the machine currently is.


I guess the post was more of a fishing expedition to see what your collective experiences were with it were.

Many thanks once again

Richard

This is what the innards look like......seems i have to take that screw out to get at that bottom spring. Judging by the rust I don't think its gonna undo too easy.

With the cover off it is surprising how the diesel seems to drip through in to this part of the casing....so I am guessing the seal behind has failed.

Is there a procedure to remove the entire fuel pump to get it re-sealed? (setting the timing for the pump and the engine on No.1)

I guess I need to start looking for a repair manual off ebay [attachment=58989]D6 fuel pump.jpg[/attachment]

This might help. I have no idea what order the software has put them in.

Some more....

Last one......

Hi Team,
thanks R.C. for taking the time to put up your S/M Pics.

The scan below shows where to bleed air from the Governor Housing after re-fitting the unit.
This fact is not in any Cat Manuals.

The bleed tap on top of the main housing near the big side plate gets the air out of the main body of the unit BUT, some air remains trapped in the Gov. Hsg. and so needs to be bled also-- if this is not done you have to crank the engine until fuel can compress the trapped air back into the Gov. Hsg., which levels out into both areas when the engine is stopped, up to a level high enough for the Inj. Pump plungers to pick up fuel and so start the engine.
This issue is repeated each time the unit is started until said air is bled out.
Cheers,
Eddie B.

You don't need to remove the entire injection pump/governor to work on the governor section.That compartment you are looking at should be dry, yes, the inboard seal has failed.
For some strange reason the parts diagram only shows one 4N2786 seal (item 10) but there are actually two used.

A big thank-you to EdB, RC, and OM for this information.
It is greatly appreciated!

All the best
Richard