Diesel Fuel in Crankcase of D47U

There is a o-ring seal between the injection pump and the fuel filter housing. This is above the pump drive. It must be rotted away. Remove the injection pump and governor to replace.

There is a o-ring seal between the injection pump and the fuel filter housing. This is above the pump drive. It must be rotted away. Remove the injection pump and governor to replace.

Rome, Thanks for the help. Looks like getting the bolts out of the back side of the injector housing will be the hardest part. Caterpillar in their infinite wisdom made some impossible circumstances. Looks like it is a line to line fit to get it out past the pony clutch.

Do you think there is a need to replace the lower seal on the drive shaft while I have it out? Looks like that just keeps oil in the pump housing and I never have to add oil.

There appears to be two seal numbers so will have to wait til Monday to talk to Cat to see what they are.

Rome, Thanks for the help. Looks like getting the bolts out of the back side of the injector housing will be the hardest part. Caterpillar in their infinite wisdom made some impossible circumstances. Looks like it is a line to line fit to get it out past the pony clutch.

Do you think there is a need to replace the lower seal on the drive shaft while I have it out? Looks like that just keeps oil in the pump housing and I never have to add oil.

There appears to be two seal numbers so will have to wait til Monday to talk to Cat to see what they are.

Thanks Toby,
I think this is probably the seal you mean on the governor side. (see photo)

How in the heck did you get to the bolts on the back of the injector?

I havent started taking anything apart but it looks like the bolts are pretty well hidden away!! :hat:

Thanks OM about the seals and the meaning of the black triangle!! 👍

Yes, that's the other o-ring I was talking about. If one is deteriorated to the point of leaking, then the other is likely in the same condition.

I just use a ratchet, some extensions, and a 9/16" swivel socket to remove the injection pump nuts between the housing and engine block, its not bad at all.

you might want to change the metal sleeve the o'ring fits over. it fits tight in the filter housing but comes right out with a couple of twist with water pump pliers it is still available at cat and now is a good time to replace it. I have found them badly pitted and pin holed from rust do to moister from lots of years of sitting. its cheap and easy wants your there and then everything is new and you have know worries.

The studs behind the pump housing usually come out with the nut. Sometimes you get lucky and just the nut comes off. When you are ready to go back together, install the studs with locktite sealer and give them time to set up.

The replacement camshaft seal (1H5959) is about as strong as a beer can. If you get in a hurry and drive it in with something that is smaller in circumference than the seal, it will warp and become garbage. Use a seal driver that is the same O.D. and it won't bend. Seal is cheap from Cat; $15-17. Must be used in many other applications.

Whatever you do, don't turn the crank on the Main when the pump housing is off or you'll loose your timing. The back of the pump housing is probably filled with fuel and dirt; cleaning it out is the worst part of the job.

Rome already told you about removing the governor first. If you attempt to remove everything as one assembly the governor will run into the pony motor clutch. If you remove the clutch you'll have unbolt the pony motor and lift it up which is going to increase your workload 4x.

I've never removed a governor on a 7U so maybe someone else can tell you if there are any traps for the unwary.

It looks like I can remove the top two bolts in the end of the pony clutch to clear the governor and pump. If my tape is correct it will give me a whole 1/4" clearance past the end of the studs unless there is something else that gets in the way!!

Might be a couple days until I get to it as my elderly mother fell and broke her hip yesterday.

Thanks again for all the help.