2 mechanical ? K B7800

[logan97]

B7800 402 Kubota loader. Bucket curl bleed down. Kubota service center replace o-ring seals to correct a bleed down problem with the bucket curl last week. Yesterday I noticed problem was not resolved.Talked with the service center this morning and they said they may have to replace the cylinders. Does this sound correct ? I also had a safety switch go out some time ago and it has been hot wired. I requested that they (Service Center) not replace the switch if the tractor was going to shut off every time I got off the seat as I am on and off a lot it seems when doing tasks. They did not replace it. The safety switch is to the right of the seat, down and above the axle.

 

[logan97]

anyone

 

[Verticaltrx]

How quickly does it bleed down? With how much load on it? Even new tractors will have some (very slow) bleed down.

How many hours are on it? Unless it has a lot of hours or you've put some bad hydraulic fluid in it I would doubt the cylinders would need to be repacked.

 

[wdchyd]

They repacked the cyls and they still don't hold..?

Replacing the cyls would mean either they didn't repack them right(easy out for them) or the barrels have scores inside (no honing equipment)....

unless the control valve doesn't hold pressure.....

Did they diagnose/troubleshoot/test..??

 

[logan97]

How quickly does it bleed down? With how much load on it? Even new tractors will have some (very slow) bleed down.

How many hours are on it? Unless it has a lot of hours or you've put some bad hydraulic fluid in it I would doubt the cylinders would need to be repacked.

load or no load the bucket or forks will come down within 1 minute or so, it is enough that it will slowly dump gravel,sand,dirt etc.... 275hrs on the tractor. The hydro fluid was changed @ 170 hrs.

 

[art]

It would be nice to know what he saw when he took the cylinders apart! There are times that slag might get through the hydraulic system and into a valve or a cylinder and score it enough so that it can't be sealed.

Could it be just one cylinder? Your still under warrantee?

 

[logan97]

It is out of warranty. The dealership is going to send a mechanic up this week to try and resolve the problem. I will update the post. Thanks Much for the replies.

 

[logan97]

mechanic was out this morning.As far as the repac he said there is only one obvious way these seal kits go.The slag, the fluid was really clean and he thought that it would be highly unlikely. He feels the curl cylinders are worn. Price $581. a piece. Was not expecting that. I am going to ride with it a while longer until it just becomes unacceptable.

 

[moship]

Logan97,

Perhaps consider this as a test to rule out or confirm the curl cylinders are the root cause.

Swap the hoses between the lift and curl at the joy stick controller. I致e included a picture from my tractor which may have a different color code than yours. The idea would be the same.

After swapping the hoses around, start the tractor and lift the bucket similar to what you have done in the past when the bucket would uncurl. What does it do now?

If the bucket height drops and the curl holds; The curl cylinders are good and there must be something else causing the fluid to bleed from the cylinder. Perhaps it is in the controller.

If the bucket height maintains and the curl still doesn稚 hold there is something definitely going on with the cylinders.

Note:
1) Before swapping the hoses around make certain the tractor is off and move the joy stick through all positions to bleed off any residual pressure.
2) After swapping the hoses around the loader will work opposite of what you are use to, so be careful. Lift will curl and curl will lift.
3) The color code on my tractor may be different and the hoses shown in the photo are from my snow blower. White and Yellow raise/lower and Blue and Red control the curl.
4) Do not forget to swap the hoses back after the test.

wdchyd posted very similar comments as to what I sent in a private message. Either the cylinder was not the problem in the first place, they did a sloppy job with the repair or they never did the packing replacement.

 

[logan97]

tops to bottoms or sides to sides ??

 

[logan97]

New Development. I had to leave for a moment this morning, (visitors) so I could not keep an eye on the mechanics visit. On my return before he left I noticed a large spot on the ground under one of the cylinders and a smaller under the other.He evidently looked at the cylinders in my absence, as he stated they were worn. I specifically asked if he checked the hydro fluid level, he replied yes it is OK,just fine.Few minutes ago I went to transfer some firewood thought I would check the hydro level before starting the engine,Bucket and Box Blade in the down position engine off.No fluid shows on the stick Kubota UDT hydro fluid correct,fill plug behind the seat,fluid level check down right of seat. Should the engine be on or off when checking ?

 

[logan97]

Update. Dealer reimbursed parts (seal kit) and 1 hr labor. Does 1hr sound correct to replace / repack cylinder seals ?

 

[wdchyd]

Yep, that's pretty much it.......1 hr each if no trouble/newer cyl.......1-2 if old/rusty or beat ect.......

Sounds about right....

 

[nike]

I read somewhere ( I wish I could remember where) that the controls were the cause of hydraulic creep. I think I would have them checked first. One bad cyclinder after 275 hours,ok, but both?????:2cents:

 

[wdchyd]

I read somewhere ( I wish I could remember where) that the controls were the cause of hydraulic creep. I think I would have them checked first. One bad cyclinder after 275 hours,ok, but both?????:2cents:

Nike,

The control valve can be the source of "Creep Down", but the only way to absolutely be sure is to troubleshoot (swapping hoses/pressure guages ect)...

Cyl seals are a wear/tear item that take a lot of stess but do wear out more often than control valves.......if the control valve was worn then it's junk and can be more costly than repacking cyls.....

Usually cyls are the first thing to suspect but troubleshooting saves the agony of guesswork....never assume....

Also if only ONE of a pair of cyls are not holding a load, then both in that circuit will creep down at the same rate......