Should Loader Bucket drop with engine shut off?? (580CK)

[1968 Case 580CK]

I have a 1968 580CK, and am doing a restoration on her. Just recently changed the hydraulic fluid, and had her running to slowly get the fluid running thru her veins. Everything was working great. However, yesterday I wanted to drop the front end bucket back down to the ground (with the engine not running). It was about a foot off the ground, and I went to the hand control and pushed it forward, but the bucket would not move at all. I tried all the lever positions, but the bucket would not ease back to the ground. I am pretty certain that this loader is supposed to allow the bucket to drop with the engine off. Can anyone give me some ideas as to what the problem might be? Could it simply be some air still in the system?

Thanks.

 

[Delmer]

I've never seen a tractor loader backhoe that shouldn't drop with the engine off. The only reason it shouldn't is if there are safety valves like on a crane etc. Typically you don't expect that level of safety under a loader bucket, especially one that old

A bent rod, rusty inside of the cylinder, maybe swollen piston packing?, could cause it not to drop also. Maybe one of the Case guys knows something I don't?

 

[1968 Case 580CK]

Delmer.....thanks for the input. Like you said, this is an antique, and doesnt have those saftey valves (except some of the backhoes with the optional saftey lock out valve). Works fine with the engine running.....Im thinking "maybe" still some air in the lines causing it? The other extremely unlikely possibility is that mud-dobbers have filled up the 2 air vents at the top of the hydraulic tanks......and air cant flow out fast enough to allow the fluid to flow back into the tank (from the loader cylinders).

 

[Grady]

My 580CK does something similar. When lowering the bucket with the motor off, it sometimes stops when it gets close to the ground. It almost seems like it isn't coming down evenly and locks up. Usually activating the bucket curl/dump lets it continue to drop to the ground. Mine has never been restored and could sure use a good going through. I remember reading something about how this machine wasn't meant to have the hydraulic pressure relieved after shutting it off.

 

[1968 Case 580CK]

Grady......bingo.....sounds exactly like the symptons I have......The bucket was only a foot or two off the ground when I tried to lower it with the engine off. As you say, maybe it was never intended to operate with the engine off. Im thinking that maybe the return flow pressure valve up near the operator's control handle is set at a certain pressure, and when the bucket is pretty low to the ground and the engine is off, then the relief valve does not open to allow the fluid to return to the storage tanks. With the engine running, maybe the pressure is higher, and all works right. Just something I had never noticed in the past.

 

[Grady]

'68 - I don't know that it was never intended to be used with the engine off but I think they recommend that you don't release the hydraulic pressure after shutting the machine down. It seems natural to drive to where you park, shut the machine off, and then drop the bucket but I'm pretty sure they say to lower the bucket(s) before shutting the machine down and not releasing the pressure afterwards. Not sure how big a difference it makes.

 

[1968 Case 580CK]

Grady....Yep, I agree......makes sense to drop the bucket prior to shut down. In my last case, I had raised the bucket to put more weight on the front axle as I was using that weight to help pry off the front axle spindle. When done, I expected to just lower the bucket by using the hand control, and not need to crank up the engine. Maybe this design reduces the chance of a sudden and fast drop of the bucket if something goes bad???

 

[Grady]

My memory isn't great but I think I remember something about it being less prone to leak if it stays pressurized which seems counter intuitive. Although I've never tried to determine which is worse, mine leaks pretty good under both circumstances.

 

[1968 Case 580CK]

My memory isn't great but I think I remember something about it being less prone to leak if it stays pressurized which seems counter intuitive. Although I've never tried to determine which is worse, mine leaks pretty good under both circumstances.

Yep, like a volcanoe less likely to blow its top with more magma pressure.....but there must be a reason for it. Funny....yours leaks pretty good either way. So far, all my seals are holding good.....no runs, no drips, no errors, as Johnny Bench would say.

 

[Budaboy]

I have a 580 B and K...
They both drop the loader bucket with the engine not running.