I have a Cat 40 Scraper that I use around the farm with the D4. The main lift cylinder was a welded mess when I bought it some 20 years ago but it works and has not been a problem. So now I got this wild hair to restore it to normalcy and replace the tires and all that along with a DuPont Overhaul. So the major point is to "fix" the lift cylinder.

I think what caused the problem initially was that someone hooked the scraper to a tractor with a high pressure hydraulic system and they pushed the cylinder out of the mount and they proceeded to do a poor job of welding to repair it.

Does anyone have pictures of a lift cylinder maybe apart or any sort of drawings of the cylinder? I wanted some ideas of what I would be getting into to repair it. Or maybe it just should have two coats of paint and forget it but I want to fix it right. Looking at the welded mess I am surprised it worked all these years.

So I am open to any and all suggestions on what to do to correct or not correct the cylinder. I love the scraper but it sure makes the D4 scratch when it gets nearly loaded as I added some sideboards for extra capacity. Couple of photos below .

It looks to me that it is just your mounting bracket that has been butchered.

Likely someone left the transport pin in place and worked the hydraulic system until they blew it out of the mounting surface.
Why do I think so? Because the one Glen (R.I.P.) gifted me was that way!
I’m taking mine out again for repairs; whoever re-welded the flange/plate for the cylinder did not have it re-bored, hence a slight ridge can be felt internally.
CAT had all of the parts I needed originally, but this time I’m going to have my local shop bore the tube and change the piston and seals to high pressure.
Please share your 40 progress.
I’m working on one of mine as well.
Best wishes, JM

juiceman wrote:

Please share your 40 progress.
I’m working on one of mine as well.
Best wishes, JM

"I'm working on ONE of mine" Have you become a hoarder of Cat 40 scrapers????????????

Or just that you have several scrapers of different sizes for different tractors and jobs.





Just being a smart a$$ ..........................................An if I ever get to a project I have been thinking about I know who to beg for a scraper.

Like JM plans to do, I also had a new piston made to with modern seals. Have done the same on D4 6/7U's and LaPlant scrapers.

Pretty good coverage of the lift cylinder in the Servicemen's Reference Book "Hydraulic Controls and Equipment". Be sure to properly align the cylinder in the draft frame.

Thanks for the comments guys. I ordered a Serviceman's Reference like OM mentioned but can't seem to find a parts book. I have the operators manual but it doesn't show much.

I'm hoping I can get a drawing from Cat for the flange as the Parts Diagram by Glum shows the Cylinder assembly PN. We have a good weld shop locally that I think can cut the flange off, weld on a new one and turn the flange on a lathe to make it true perpendicular to the cl of the bore. Then I will have to send it off to Salina KS to get the hydraulics and bore redone and a new piston. Might find more surprises when I get into it but it should not be too bad.

As a note I made a pressure regulator to use to limit the pressure to 1100 PSI so if I pull it behind a Green Machine I won't damage anything more. (Actually the pressure is adjustable)

Thanks again.

Neil,
This is a farmer design but is simply a hose between the high pressure side and the return with an adjustable sprayer valve in the bypass line. So if the pressure builds over 1100 PSI or whatever the setting, it just bypasses back to the return and does not build over 1100 PSI in the high pressure line going to a cylinder or whatever. I think the max setting is 1200 PSI on my spray valve but one of the tractors I have is about 2250 PSI but the bypass limits the "seen" pressure to 1100 PSI or whatever the setting. .

In theory it operates like the relief valve in an engine so the oil reaches a certain PSI and then is bypassed. Many tractors have adjustable hydro pressure settings but it usually involves shims etc. to adjust and not something you can do instantly.

Might consider a hydraulic bowl conversion...