D2 5U75xx hydraulic cylinders

Yah, some days are like that. Where did you source the cylinder parts?

Old Magnet, got the parts from my Cat dealer in Mi. Never problems in the past. Someone obviously screwed up in the OD dimensions of the seal ring. Should have been just six to do both cylinders but the originals were six to each cylinder. Part numbers were changed to show three wider rings per cylinder. That number was changed to go back to six rings per cylinder. I ordered the wide ring number and got the narrow rings, one set short of total. Of all the cylinders I have repaired over the 45 years, I have never had one that the sealing rings fell straight through the cylinder. Even the old ones don't fall through, although they are worn. Makes you want to pull your hair out! The manual I ordered only had partr of the engine listed, no attachment section. All other parts books I have have attachment sections. Don't know what happened there. Cheers, Larry.

Here's some numbers...

Rings 8F2685 = 7J8879 = 4J2637

Packing 3F9609 = 1K7107

Seal 1B2418 RPB 9H2258 = National 450083

How do these compare with what you got?
Doesn't appear to be any shortage of these number parts out there.

On the D330C engine were you looking for tractor application or Industrial Engine?

Old Magnet, I got the 7J8879 rings when I ordered the 8F2685. Part number 4J2637 subs up to 7J8879. References are: PB Ja 28/71, PB Apr 12/65. and Jun 12/62. I have not had time to check if I have these old parts bulletins, have some, not all. Just for fun I installed a ring (7J8879) on one of the 8F2656 pistons and it still fell through the bore. Bore appears to still be standard. Ring had a .074 end gap though. On the manual I ordered media number UEG0125S for the D330C industrial engine. This book is for my serial number but the attachment section is not with it. i have other industrial engine books and they all have the attachment section, It calls for 92 pages in the media number and all I got was 44 pages.There is no listing for radiators, water lines and other parts that may be required for an industrial engine. Just going to have to rattle some chains tomorrow. Thanks for your info. Cheers, Larry.

Hi Team,
here are the only PB's I have as per Larry's list above. I have various hard bound PB's from Jan 1955 to Dec 1970.

The Apr 12 65 PB tells of the full ring teflon rings for later design cylinders--see Serial No list for the Blades these apply to.

Hope this helps.

Cheers,
Eddie B.

Thanks Ed, I have some older servicegrams from the 40's and PB's into the late 60's but nothing in the 70's. It appears that most of these items for the D2's has been discontinued. While I was at at a hydraulic supply place today the owner called up a supply place in British Columbia and there was someone there looking for the same seals as I was. You would think that Cat would have some parts for these old girls as there are a number of fellows restoring them. I guess that they are forgetting that these old machines are what made them what they are today. What I don't know is where the quality inspection chaps were when the seals I got were machined. Someone definitely screwed up or does not know how to use a micrometer. Probably union help! Cheers, Larry.

Your not alone. Cat has lost it on the early D4 cylinders as well. Had to provide backup rings for the cup style piston seals to keep them from blowing out.

My response Larry is that product quality usually goes to pots when companies go away from being a union shop. If you look at the data that's out there its pretty typical in all manufacturing that the quality suffers when a company goes non union and hires the cheapest labor they can get. Or imports from a substandard labor country. Labor does not take a lot of pride in their work when they can't make a living wage. Unfortunately the price of the part does not go down. Only the quality suffers while the company gets richer on labor s back. Don't take my word for it. Look for yourself. There are many universities studies on it that always come up with the same conclusions even though the liberal bums hate to admit it.