Problem with curl cylinder?

[radman1]

Update. TC is still at dealer. So far have not found much wrong. Cylinder is OK. Checking other possible problems in the control valve and relief valve.

 

[DEWFPO]

The mechanic was out to check my curl cylinder yesterday. He wasn't sure what the spec was but thought it was 1.5" movement over 10 minutes or so. Doe anyone know what the actual spec is? Is there a temp spec as well?

Anyway. I was right at that when he checked it but the oil wasn't all that hot. The hotter the oil, the faster the cylinder looses pressure. The cylinder moved about 2" in about 15 minutes. When I'm blowing snow for 2 hours and really working the hydraulics, it drops even faster.

He checked the cylinder itself by getting the hydro oil warm, disconnecting the return pipe, plugging both ends and putting curling the cylinder in the max position for several minutes at a time, in both directions. He said if there was a seal leak, it would push the cylinder out. It didn't so he concluded the cylinder was fine.

He said the problem seems to be with the control valve or relief valve, I can't remember which one he said. It's under the joystick and it has rubber seals. He said some pressure will be lost past the spindle valve, but it appears my rubber seals are leaking pressure. I hope he's right. He didn't have a seal kit with him so he's going to have to come back.

DEWFPO

 

[radman1]

The mechanic was out to check my curl cylinder yesterday. He wasn't sure what the spec was but thought it was 1.5" movement over 10 minutes or so. Doe anyone know what the actual spec is? Is there a temp spec as well?

Anyway. I was right at that when he checked it but the oil wasn't all that hot. The hotter the oil, the faster the cylinder looses pressure. The cylinder moved about 2" in about 15 minutes. When I'm blowing snow for 2 hours and really working the hydraulics, it drops even faster.

He checked the cylinder itself by getting the hydro oil warm, disconnecting the return pipe, plugging both ends and putting curling the cylinder in the max position for several minutes at a time, in both directions. He said if there was a seal leak, it would push the cylinder out. It didn't so he concluded the cylinder was fine.

He said the problem seems to be with the control valve or relief valve, I can't remember which one he said. It's under the joystick and it has rubber seals. He said some pressure will be lost past the spindle valve, but it appears my rubber seals are leaking pressure. I hope he's right. He didn't have a seal kit with him so he's going to have to come back.

DEWFPO

I don't quite understand the specs for leakage. At first my dealer said it checked out fine and within Bobcats specs. However, I asked him how he checked it. It was just with the bucket on the TC. Told him, when I use my sweeper, I can visibly watch the broom tip down and it wasn't like that before. He did say it should not do that with a broom on the front. I can't be tipping my broom back every 1-2 minutes because of the problem.

 

[DEWFPO]

I don't quite understand the specs for leakage. At first my dealer said it checked out fine and within Bobcats specs. However, I asked him how he checked it. It was just with the bucket on the TC. Told him, when I use my sweeper, I can visibly watch the broom tip down and it wasn't like that before. He did say it should not do that with a broom on the front. I can't be tipping my broom back every 1-2 minutes because of the problem.

This supposed 'spec' is ~1.5 " of cylinder movement over 10 minutes of time (if that is the correct spec.). Mine moves faster when hot so there should be some hydro fluid temp spec as well. In any case, the mechanic is trying to say 'it is in spec (barely) and I am trying to push him to do something about it because it's unacceptable to me and can be down right dangerous if I forget to pull it up often when driving down the road.

DEWFPO

 

[J_J]

This supposed 'spec' is ~1.5 " of cylinder movement over 10 minutes of time (if that is the correct spec.). Mine moves faster when hot so there should be some hydro fluid temp spec as well. In any case, the mechanic is trying to say 'it is in spec (barely) and I am trying to push him to do something about it because it's unacceptable to me and can be down right dangerous if I forget to pull it up often when driving down the road.

DEWFPO

Why not take a video and tell the mechanic /owner that you have tried to get it fixed, and they all procrastinate. Then send the video to the president of Bobcat.

 

[radman1]

This supposed 'spec' is ~1.5 " of cylinder movement over 10 minutes of time (if that is the correct spec.). Mine moves faster when hot so there should be some hydro fluid temp spec as well. In any case, the mechanic is trying to say 'it is in spec (barely) and I am trying to push him to do something about it because it's unacceptable to me and can be down right dangerous if I forget to pull it up often when driving down the road.

DEWFPO

1.5" of cylinder movement in 10 minutes makes a big difference on how far an approved attachment like a broom tips down. Brooms are not designed to run with much weight on the bristles and most of the weight hangs far out front. My TC has been in the shop 10 days and now they are checking out a few things in the spool valve. They are waiting on some parts.
Yours seems much worse than mine. I have a check valve. I may just install it if they can't/won't fix it. I may just install the check valve anyway. I want to use my 11' manlift on a job in a few months. I can't have any significant tipping when it is in the air.
The boom lift cylinder is very stable.

 

[DEWFPO]

I haven't measured my boom/lift cylinder but I haven't noticed any obvious problems.

The curl problem is fairly obvious when you use pallet folks or the bucket to lift something up and hold it there while you work on whatever it is you are lifting.

If you install the check valve, let me know if it solves your problem. I'm going to continue to try to get the dealer to solve this but if he can't I will.

DEWFPO

 

[radman1]

I haven't measured my boom/lift cylinder but I haven't noticed any obvious problems.

The curl problem is fairly obvious when you use pallet folks or the bucket to lift something up and hold it there while you work on whatever it is you are lifting.

If you install the check valve, let me know if it solves your problem. I'm going to continue to try to get the dealer to solve this but if he can't I will.

DEWFPO

Dealer warned me that I may not like how the tilt cylinder may work with the check valve. I have used them on TNTs for 2 different tractors and think they work great. He thinks I may not like how the controls work with check valve and it may chatter. I have not noticed any problems on my other cylinders. He had a customer use one on a all terrain construction lift and it did not work well. I have 2 Vickers double piloted check valves that I bought from Ebay. 3000 psi with 12gpm flow. Just need to get a few other fittings and hoses.

 

[J_J]

Dealer warned me that I may not like how the tilt cylinder may work with the check valve. I have used them on TNTs for 2 different tractors and think they work great. He thinks I may not like how the controls work with check valve and it may chatter. I have not noticed any problems on my other cylinders. He had a customer use one on a all terrain construction lift and it did not work well. I have 2 Vickers double piloted check valves that I bought from Ebay. 3000 psi with 12gpm flow. Just need to get a few other fittings and hoses.

Did you ever try another valve as a test valve to see if the cylinders does the same thing. In your parts manual, does it say that the spool has o-rings, if so, pull that out and replace the o-rings.

 

[SPYDERLK]

With no dirt in the tree spade, the curl cylinder will tip the front of the spade up and down and not go into relief. With the spade on the ground the curl cylinder is in the midportion of its stroke. When I had dirt in the spade, the the boom could lift the back of the spade. As the boom lifted the back of the spade higher, the curl cylinder would extend at least several inches from the weight of the spade/dirt. It would extend without any input/movement from the hydraulic control. It seems like the sheer weight of the lift was causing oil in the curl hydraulic circuit to bypass somewhere.
I can raise my front wheels with the curl cylinder when tipping the spade down and it will stay there.

I know further on the dealer says the cyl checks out, but from the above I think the nut on the piston end of the ram is loose.
larry