loader / backhoe stopped working

brooktre

Member
MF 202 with 102 loader and 185 backhoe. Loader and backhoe hydraulics are run from pump on front of tractor (driven by crankshaft).

I was using my loader in the morning without any problems. After lunch, I started to use the backhoe. After about 4 -5 scoops, the hydraulics quit. Now I get no movement with the loader or the backhoe. Hydraulic fluid level is OK and looks OK. I pulled off the pump and it does turn by hand. Also the crankshaft extender that drives the pump is turning. I don't see any external leaks or issues with the suction side (no collapsed hose). I have a pressure guage, but need to get some fittings to connect it. Does anyone have any ideas for further troubleshooting?
 
How long has it been since the hydraulic
fluid/filter have been changed.if it has
been a while and the fluid is milky,start
by changing the hydraulic filter and
changing fluid.

Rock
 
(quoted from post at 19:02:48 08/05/20) MF 202 with 102 loader and 185 backhoe. Loader and backhoe hydraulics are run from pump on front of tractor (driven by crankshaft).

I was using my loader in the morning without any problems. After lunch, I started to use the backhoe. After about 4 -5 scoops, the hydraulics quit. Now I get no movement with the loader or the backhoe. Hydraulic fluid level is OK and looks OK. I pulled off the pump and it does turn by hand. Also the crankshaft extender that drives the pump is turning. I don't see any external leaks or issues with the suction side (no collapsed hose). I have a pressure guage, but need to get some fittings to connect it. Does anyone have any ideas for further troubleshooting?

Did you check the condition of the splines, or key, on both ends of the pump drive shaft? Also the condition of the couplings they go into? The shaft could be turning when it is not loaded by the pump building pressure when you are operating the hoe or loader.

How is it plumbed? Does the oil go from the pump to the hoe then the loader? Any quick couplings that could have come apart or failed?
 
I had the same thing happen to me not long ago with my 8N ford with loader and backhoe. The hub and drive shaft going to the pump has stripped out so when you looked at it running the pump was spinning but when you tried to work any thing the shaft and pump stopped turning and only way to can see that happen is if you have 2 people one to watch the pump and shaft and one to try to work the machine
 
On my tractor, the pump driveshaft threads into the plate that mounts to the front of the engine, so there are no splines on the engine side. I didn't remove the driveshaft to inspect the threads but will. On the pump side there is a woodruff key that is fine.

I don't think you can see the pump or driveshaft turn on this tractor when the pump is mounted, but I may be wrong. I did listen to the pump when it was running and there were no odd noises. I didn't have a 2nd person so I couldn't listen when trying to operate the loader.

The connections / layout are all as designed (there are no modifications or aftermarket items). The pump goes to a diverter / selector valve so you can choose loader or backhoe. Usually when I select either, the high pressure line jerks with the change in pressure. That is not happening now. It seems as if there is no high pressure.

The fluid and filter were changed a couple of years ago and this unit hasn't been used much in the last few years. I would estimate less than 50 hours since the fluid / filter change. It is also stored out of the rain except for the backhoe.

Although there was no noise when the hydraulics stopped, I wondered if the high pressure relief valve had stuck open. I have the book on how to set the relief pressure, but not I'm not sure how to check if it stuck.
 
(quoted from post at 22:06:13 08/05/20) The connections / layout are all as designed (there are no modifications or aftermarket items). The pump goes to a diverter / selector valve so you can choose loader or backhoe. Usually when I select either, the high pressure line jerks with the change in pressure. That is not happening now. It seems as if there is no high pressure.

Actually, the pump hose goes to the loader control valve and then the diverter valve is plumbed to that valve. The high pressure relief valve is part if the loader control valve.
 
i have a 202 same thing happened to me years ago.. the key turned in the coupling on the pump end. got it cleaned up at a machine shop new key and it has been going ever since.
 
It's fixed! Thanks Farmer Rock, Jim, Old & Clarence for your help.

It was a mangled woodruff key on the crankshaft side of the coupler.

I had forgotten how it was all connected. The pump driveshaft threads into a plate mounted to the crankshaft pulley. There is a coupler that fits half over the pump driveshaft and the other half over the hydraulic pump shaft. Each half has a woodruff key. The outer pump side was good, but the inner crankshaft side was damaged. Fortunately the slots that hold the key were ok.
 

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