Simple hydraulic problem!

[Dry Rot]

I know this is going to be a stupid question with an easy fix!

OK, I have a 56 bale carrier that's been sitting in the nettles since last year. It's the one you back onto a stack of bales, then close the arms, then lift the stack. So, basically, two double acting hydraulic rams, one controlling each action.

I connected the two pairs of hoses to the four spools at the back of the tractor (MF390). One pair of pipes goes to the 'tilt' and the other pair to the 'arms'. Yes, I did trace them back to the cylinders! Operating the lever closed the arms -- then stuck. No movement to open the arms, but some fluid leaking from connectors at cylinder. Tightened up the leaking connector, so no more leaking but no opening and closing the arms either, just as before. There is movement in the pipes indicating that something is happening, but no action!

The other pair of pipes work the lift just fine. The body of the carrier tips and lifts just as it should.

OK, so now I've swopped the pairs of pipes over, left to right. I get the same actions on the carrier. Good tilt but no action closing or opening the arms. So it seems there is nothing wrong at the tractor side.

So, presumably something is happening (or not!) in the ram operating the arms? But what am I looking for? Thought I would ask you guys before taking things apart. A simple air lock? Or a blockage? Not enough fluid? Your help would be appreciated!

 

[bodo]

I know this is going to be a stupid question with an easy fix!

OK, I have a 56 bale carrier that's been sitting in the nettles since last year. It's the one you back onto a stack of bales, then close the arms, then lift the stack. So, basically, two double acting hydraulic rams, one controlling each action.

I connected the two pairs of hoses to the four spools at the back of the tractor (MF390). One pair of pipes goes to the 'tilt' and the other pair to the 'arms'. Yes, I did trace them back to the cylinders! Operating the lever closed the arms -- then stuck. No movement to open the arms, but some fluid leaking from connectors at cylinder. Tightened up the leaking connector, so no more leaking but no opening and closing the arms either, just as before. There is movement in the pipes indicating that something is happening, but no action!

The other pair of pipes work the lift just fine. The body of the carrier tips and lifts just as it should.

OK, so now I've swopped the pairs of pipes over, left to right. I get the same actions on the carrier. Good tilt but no action closing or opening the arms. So it seems there is nothing wrong at the tractor side.

So, presumably something is happening (or not!) in the ram operating the arms? But what am I looking for? Thought I would ask you guys before taking things apart. A simple air lock? Or a blockage? Not enough fluid? Your help would be appreciated!

The spool not working properly might be set to single acting. There is a screw on the spool slice where you put the pipes in that screws in and out, wind this the other way and it might well sort it

 

[Zebbedee]

Are the arms seized? If it is a double acting ram with a hose at either end and the hoses go directly to tractor then there is not much to go wrong if tractor is producing hyd flow and pressure, so if that is all correct either the gates are seized or seals bypassing in the ram, bit seals would be unlikely tbh

 

[DrDunc]

Swap the probe ends over on the squeeze ram pipes.

If the ram works the other way, then replace probes

 

[Dry Rot]

The spool not working properly might be set to single acting. There is a screw on the spool slice where you put the pipes in that screws in and out, wind this the other way and it might well sort it

I've swopped the pair of pipes over and get the same problem. So, pipe 1 and 2 on the left and 3 and 4 on the right -- arms don't move.

Swopped pipes over so pipes 1 and 2 now on connectors 3 and 4, tilt works but not arms.

So everything must be OK on the tractor side, surely?

 

[Mursal]

The squeeze frame is in and wont come back out, is it?
Some have a large spring to pull the frame back out the ram just works one way.
If you leave the spool in the release position, can you "help" the frame back out?

 

[Dry Rot]

Are the arms seized? If it is a double acting ram with a hose at either end and the hoses go directly to tractor then there is not much to go wrong if tractor is producing hyd flow and pressure, so if that is all correct either the gates are seized or seals bypassing in the ram, bit seals would be unlikely tbh

My reasoning also. It'll be something stupid!

(I hate bloody machinery! It took ten minutes to sort someone's dog yesterday. Now that I can do! Would shouting at it (bale carrier, not dog) help? Kicking doesn't seem to work.).

 

[Dry Rot]

The squeeze frame is in and wont come back out, is it?
Some have a large spring to pull the frame back out the ram just works one way.
If you leave the spool in the release position, can you "help" the frame back out?

I'll try that. Thanks. Sounds logical.

 

[Dry Rot]

Ah! I think I have a split hose. I didn't notice with all the fluid supposedly coming from the loose connection. One of the long ones, of course!

Thanks, guys.

 

[mikep]

Ah! I think I have a split hose. I didn't notice with all the fluid supposedly coming from the loose connection. One of the long ones, of course!

Thanks, guys.

If that doesn't work go back to @DrDunc suggestion. Sometimes one of the probes (male connector) for some reason looks fine but doesn't open properly. Swapping the probes over shows this up.

 

[Dry Rot]

If that doesn't work go back to @DrDunc suggestion. Sometimes one of the probes (male connector) for some reason looks fine but doesn't open properly. Swapping the probes over shows this up.

Thanks, but definitely a split hose. I know about getting the couplings squeaky clean.

Just looking online to see if I can get one mail order rather than a 70 mile round trip to town. No markings on the hose but OD seems to be 17mm and 7mm ID inside the metal coupling on the end, so I'm assuming the internal diameter of the hose will be the same.

 

[Mursal]

Have you a manual fitting (tighten into the pipe with spanners) that you could use as a joiner?

 

[Mursal]

As the grab will be a few years old, the pipe will be either 1/2" if its like a tipping trailer pipe in size, or a smaller 3/8" more flexible.

Reusable hydraulic pipe ends

 

[Mursal]

So two reusable ends and a straight adapter might get you away? Just check if you have single or double layers of wire in your pipe. The outer part that was already on the hose in the diagram is left hand thread and goes on with a spanner.

 

[multi power]

If you know the sizes easy to get a replacement pipe in the post

 

[Mursal]

Forgot to mention, 1/2" the actual pipe will be approximately 12.5mm inside unlikely to be that big
3/8" will be approximately 9.5mm inside.

The only problem with getting a complete pipe what threads did they use on the ends?

 

[Sharpy]

Almost certainly bsp, 3/8 or 1/2". Could tell from a photo.

 

[Dry Rot]

I'll stick a photo up tomorrow. Yes, I might have some of those re-usable ends. But can you still get them? I heard they'd been banned because they are dangerous?

I did a quick Google on mail order made up hoses and they didn't seem that dear, but no doubt I read the wrong spec!

 

[agrimax]

Reusable fittings are not illegal. Can still be got easily. Especially online. Hose repairers tell you they're not legal as they don't want you buying them as it means they'll sell less new hose or complete assemblies!
It is illegal to repair a used hose though, whether it's with a reusable end or crimped......

 

[Dry Rot]

New hose purchased over the counter this morning. £32 including VAT.

Online supplier would not quote without sight of the old hose. "Too many mistakes". I offered measurements and photos but same answer.

New hose now installed but haven't had a chance to try it yet. So I think the problem is probably solved.

Thanks to everyone who contributed!