Model 67 bucket not holding position when back blading

[JD750]

I just purchased a John Deere 750 with 67 FEL with 550 hours on it. Ran it all weekend digging and moving dirt and it worked perfectly. This is my first compact tractor.

The machine does not show any leaks anywhere and the FEL easily raises the front end of the tractor but when I am back blading the bucket will just curl and does not hold position. I realize this is a high-load operation but shouldn't the bucket be held in position when dragging it backwards? The lift cylinders have no issue holding position.

From my research, it appears that the internal seals could be leaking which would not surprise me on a 30 year old machine, is my diagnosis correct? If so, is this the right seal kit to order?

AM118390 John Deere Loader Lift & Tilt Hydraulic Cylinder Seal Kit 67 Rod & Bore

Thanks

Chris

 

[jenkinsph]

You need to know whether the problem is valve or cylinder related first. I would try swapping the lift hoses with the curl hoses and see if the problem follows the curl cylinders or the valve.

I should add that when back blading with an ag fel I would keep the bucket flat or close to flat. I would not tuck the bucket to the rear as this can damage the fel.

 

[JD750]

You need to know whether the problem is valve or cylinder related first. I would try swapping the lift hoses with the curl hoses and see if the problem follows the curl cylinders or the valve.

I should add that when back blading with an ag fel I would keep the bucket flat or close to flat. I would not tuck the bucket to the rear as this can damage the fel.

Interesting, maybe I am overloading the FEL then. If I put the bucket near to flat, it holds the position fine.

One other oddity is the curl has an "automatic" function where you pull the lever and it will hold open fully dumping the bucket. It does not pop back to neutral at the end of the cycle, should it?

I will try swapping the hoses this weekend.

Chris

 

[Gary Fowler]

Interesting, maybe I am overloading the FEL then. If I put the bucket near to flat, it holds the position fine.

One other oddity is the curl has an "automatic" function where you pull the lever and it will hold open fully dumping the bucket. It does not pop back to neutral at the end of the cycle, should it?

I will try swapping the hoses this weekend.

Chris

This sounds like a "float" detent and should be only on the lowering of the bucket. Push to the detent (handle stays put) and the bucket would float up and down with contour of the land. This should be in the lowering position not raise and it wont pop back out till you pull it.
However, If not and it is a regular hydraulic valve like you have on rear remotes (could the owner have hooked it up to rear remotes) then it is a detent that allows you to pull the lever all the way back for raising an implement and when it gets to the end of the hydraulic stroke, the handle should pop back to neutral. DONT leave it in the detent position as it causes the pump to go into relief mode which is bad for the pump and tractor if done for a long period of time as it heats the oil too much.
Post some photos of your rig so every one can get a look at the setup.

 

[JD750]

DONT leave it in the detent position as it causes the pump to go into relief mode which is bad for the pump and tractor if done for a long period of time as it heats the oil too much.
Post some photos of your rig so every one can get a look at the setup.

I think you are right, when the lever is all the way up, the pump does go into relief mode and the lift hydraulics slow way down.

So the "float" feature will work in the middle of the buckets travel? What is the use of this function?

Maybe there is nothing wrong with my bucket and I am just using it wrong. I will post photos later.

EDIT: Really hard to get a good photo of the valve since it is tucked between the tractor and the loader frame. I think the FEL is plumbed incorrectly, if I understand it properly, the float function is for the boom cylinders not the smaller bucket cylinders. Right now the float function works on the small bucket cylinders not the large boom cylinders. I think I need to swap 2 of the hoses to get this to function correctly.

Chris

 

[JD750]

Alright, did a little troubleshooting today, man the plumbing really is a puzzle! Found a couple of issues, firstly the boom and the bucket hoses were reversed. This caused the left lever to control the bucket and made the "float" function useless. I swapped the hoses and everything is great now. Lots of power, back blading and front pushing work great. I also see how the float feature works which is great for smoothing soil after I dump it. My only problem is I have no overpressure (relief) valve on the curl function.

Now here is the real puzzle, the whole thing is plumbed wrong! There is a relief valve for the bucket to protect the hydraulics at the end of the stroke but there isn't one for the boom lift. For some reason, one of the boom hoses is plumbed through the relief valve. It has been that way for a long time which really puzzles me. I tried to fix that as well tonight, but one of the hydraulic hoses seems to be rusted shut. I sprayed it with PB blaster and will tackle it again later.

The rubber on a couple of hoses is cracked, can I just wrap them with tape or should I replace them? How are the hydraulic hoses from Surplus Center? Do I need 1 wire or 2 wire hoses?

Thanks

Chris

 

[Zebrafive]

I have used their hoses without problem. I bought two wire to get JIC fittings. They were not an option on one wire hoses. Either would have a high enough rating.