I'm really hoping somebody has a repair procedure or knows how to change a hose on a Cat 931B loader. The boom cylinder hose for lowering on the right side blew. The boom was up so it's not too hard to get off on the cylinder but the other end under the floor plate looks to be a real pain to get off. The 2 boom hoses are clamped to bracket with a bolt from underneath you can't get at. There are 2 steel lines with bulkhead fittings above the hoses on the same bracket. I'm guessing you have to take the bulk head fittings right out in order to lift the bracket up enough to get the clamp bolt underneath off. If someone has done this or has the repair procedure would be greatly appreciated.
I just had one blow out on my 1993 935CSeriesII which may have the same design as yours. I attached a picture to verify. If it is not as difficult as it looks, and I am not a mechanic by no means, and also this is my first piece of equipment First I removed the outer hose so I could get to inner hose. The bolt that tightens the clamp I accessed with a 9/16 socket from the cylinder end. If your reach back far enough you can just barely get a socket on it. This probably took longer than any other part of the repair as you can only turn it a little at a time. Then I wised up and used a 3/8 air ratchet to tighten it back up. On the fitting though I did have to use a handheld propane torch to heat the fittings before they would loosen. And btw: Local Cat dealer made the hose,and my first reaction I thought it was too short based on the other 3 old hoses, (all four are same part # on mine). But after installed I can see that all the slack the other 3 have is not needed. Sorry pictures are not rotated correctly. They are correct on my computer, not sure why they changed at post. Oh one more thought: I could have save myself a great deal of effort if I would have lowered boom slightly,(after attaching hose to bulkhead end of course) then hose would not have been stretched so tight when I was attaching it to cylinder end.
Yes, it's the same set up. I got the hose off. I took the bulkhead fittings for the bucket cylinder right out to have room to loosen the hoses below. I dropped a 9/16" wrench and of course it fell right the oil pan I had underneath but that's when I realized it was open under the floor board. I took an extension on a ratchet and got the bolt on the clamp loose by reaching in under the track from the side. I went to the Cat dealer but they don't have the dies or anything else for the reusable fittings anymore. I'll just wrap some tape around the crimp till it's about the same size to fit in the clamp.
Even though the fitting Cat used were the crimp type, it seemed to snug up just fine in the clamp assembly, but I did not think about testing it to the extreme. Good to know the 9/16 bolt was accessible from underneath. I have a feeling it’s only a matter of time before I get to change another. Mine blew out at the pinch point where it exits the clamp. Tell you something funny about accessing hoses and such from below. I spent most of a Saturday underneath loader changing out both torque converter hoses, and spent what seemed like an hour or two struggling to reach back into the recessed area at bottom of radiator to connect hoses. Finally after I finished and crawled out from underneath, for some reason I just happened to remove one of the engine side panels as I have done many times, and low and behold, right there in plain view was the bottom of radiator, and in easy access were both torque converter hose and fittings. Still kicking myself for that one.
I never realized it was open to the ground under that side floor board. It was dark when I looked and then my generator ran out gas so I couldn't take a better look. The boom is blocked about 1/2 way up and I thought about trying to access the bolt for clamp from under the cylinder but I broke my middle finger on my right hand on Wed. and it's got a big gauze wrapped around it. I have a quick attach backhoe and was digging in some soft ground and all of a sudden lost hydraulics and saw a big pool of oil. Had to shut the machine off right away. The main hose from the pump to the loader control valve came apart. It didn't blow and was actually in really good shape with a perfectly skived end for the cat reusable fittings. Problem was someone tried to use a non cat hose (smaller diameter) with cat fittings and used a piece of tin for a shim and that's where it came apart. The other end had a piece of plastic for a shim. I had to lay in 60 litres of oil under the machine to get the back 2 bolts for the belly pan out. Then because the machine was sunk in the soft ground the belly pan wouldn't drop far enough to get it out. Finally after fighting with it for 30 minutes got it out. Then I had to lay in the oil again to get the hose off and a 3rd time to put the new hose on. I barely had enough room to get under the machine. There was no way to pull the machine out with the backhoe stabilizers down. At least I could move the machine to a better location to put the belly pan back on. I like the machine but it's so tight to try and work on anything. I just put a rebuilt starter in it and after using it for a day, didn't want to do anything the next day. I thought the battery went dead so boosted it and only after trying the button about a dozen times did it start to click and finally turned over and started. I don't think the battery was dead at all cause I just had the alternator done. I'd bet money the solenoid stuck. If the rebuilt starter acts up anymore and I have to pull it out again, the repair shop's going to be eating it.
Sounds like my day a few months back. The builders of these machines had no pity for those working on them!! Major PITA! I have since replaced the MP bucket feed tubes as well.
Mr Miller, Words fail me after seeing your job and imagining how much work that must have been. Great job! I did finally discover that it is sometimes easier to take a sawzall to the old hose right at the fitting, and then I can get a socket on it. This is just the ones that I cannot get a wrench to loosen btw I have been careful to make sure I let fluid bleed out afterwards to clean out any metal shavings. But now that I think about I wonder if there is a chance that cutting through old hose could containment? I notice in your pile of old hoses I dont't see any that appear to have been cut. So maybe I am developing a bad habit?
Actually got the hose back on fairly easily after knowing how it goes together. I had the steel line that runs from the loader control valve to a backhoe quick coupler wear through because it wasn't clamped properly. Would have been impossible to remove so took a mini hacksaw and cut the line off a couple inches back from the leak and saved the complicated bend part that comes out of the loader control valve. Then I had it flared for a JIC fitting and used 2 hoses with a 90 deg. elbow to replace the steel line.
I did take a 4 1/2" grinder with cut off wheels to the old hose crimps deep into the shovel frame. Get the hose out of the way take the fittings out but only need to cut the crimps down one side get the pressure off and twist to cut thru the other side 180 degrees from first cut. I own a couple sets of crow foot wrenches, some 3/8" drive others 1/2" drive, tough spot to use but did fine for tightening as far as needed on new hoses. If don't cut the hose no contaminants put in system.
There's definitely a complicated maze of lines and hoses on these things that some would be impossible to change without removing half the machine.