I recently bought a 680b Case Backhoe. It has hydraulic brakes, and as is common, the slave cylinders are leaking. The repair/replacement parts are mostly unhaveable. I found a near replacement for them in a slave cylinder to fit an IH CX100. It only requires slight mods to the mounting. However, the cylinders say to use only mineral oil in them. I did an online search and I get conflicting answers as to using dot4 brake fluid in place of mineral oil in the system. I have sent an e-mail to the manufacturer, but they are based in Turkey, so I am not too hopeful on a response. I am not above getting rebuild kits for the master cylinders, to change out the seals, and running mineral oil in the system if that is what it takes. Has anyone run into this situation before. I plan on taking a few pictures and posting them if this works, out so anyone that needs this information, on this brake system, might find it helpful. Thanks in advance, I will keep this post updated.
Dot 3 brake fluid will destroy the seals in a cylinder that requires mineral oil.
I just pulled the master cylinders off, and while doing that got to thinking, perhaps that machine called for mineral oil instead of brake fluid. They have a 7/8 bore, and the # 2225119 embossed in them. [that may be just a casting number] I do not have a manual that tells me one way or the other. If anyone knows I would appreciate the info.
If you plan on keeping your 680B very long I would advise you to get a service manual for it. Be careful and avoid one for sale for a 680B/680C. You need one for a 680B.
I found a parts manual, but have not located a service manual as of yet. I see a few sites that offer it as a download, but they seem questionable at best. I would rather purchase a printed one. I will keep searching. I have seen a few rebuild kits offered that I think are the correct ones for my master cylinder, and they say to only use mineral oil in them. Right now, I am trying to confirm that they are the right kits. Thanks for the reply
If you have an eBay account printed manuals are available there. I would dismantle the old master cylinders and inspect the bores before buying kits. They may be badly scored.