3PH arms won't raise on KAMA 454

[Paddy]

I got a strange one. I loaned my KAMA to a friend while I was out traveling. When I came back he said the 3PH arms would not raise...with out taping the FEL joy stick. So I went over to take a look. Sure enough. It would lower just fine. Try to raise, nothing until you give the joy stick a bump. I disconected the lines to the FEL and re-actached as if I was removing the FEL to isolate the problem. Still won't go up and now of cource I can't bump the joy stick on the FEL to get her moving/ So I re-attached the FEL lines. Problem continued.

On the left side of the lift box, near your left calf when sitting on the tractor is a adujusting bolt/valve to bypass the lift arms for external uses. I was told that might have been turned in. Checked it and made sure it was max out. Still no action.

Any ideas??

Patrick

 

[bluechip]

You could remove the cap on the output elbow and see if the oil is being diverted to this port. (it will flow out the uncapped outlet when the controls is raised). if so, the plunger that the screw pushes against could be stuck in the off position. hydraulic pressure normally forces this plunger against the adjustment screw. Also check the linkage under the lift box cover, there is a turnbuckle style adjustment for the draft control. I have seen it work loose and cause problems.

 

[Paddy]

Thanks Chip. More to try.

 

[Paddy]

Chip,

I pulled the lift box cover. Very easy. The linlkage to the Draft control at the top portion of the 3PH was very loose. It's a turnbuckle type adjustment. The location as found was not pulling the rod out of the top of 3PH until the Draft lever was nearly down. By shortening the adj rod, the Draft link started moving nearly from the top. I thinking at this point I have found the culprit. But to no avail. In fact now the trick of bumping the FEL joy stick did nothing. So I lengthened the adj rod back in the direction it came from and past. Did not raise on it own but still if I bump the FEL joy stick, it raises. So thinking I had the direction right, I adjusted it as far as I could. Still no action.

Another pc of info. While my friend had the tractor, he had attached my yard box. The draw bar was left on...accedently. There was interference to the point the draw bar has a 20 deg bend up. Does any one think if the 3PH was trying to lift and hitting this draw bar, the bypass valve in the 3PH has failed? Or since my friend was doing some heavy yard box work the Draft control linkage was bent down below where I can't see with out draining?

Thanks for any help. This is quite a quirky thing.

 

[greg_g]

While my friend had the tractor, he had attached my yard box. The draw bar was left on...accedently. There was interference to the point the draw bar has a 20 deg bend up. Does any one think if the 3PH was trying to lift and hitting this draw bar, the bypass valve in the 3PH has failed? Or since my friend was doing some heavy yard box work the Draft control linkage was bent down below where I can't see with out draining?

I first thought bypass valve myself, and that still may be the case. But I am having a hard time with this last little tidbit you threw in. My KM454 drawbar is a solid steel bar that is at least an inch and a half thick. How on earth could a "yard box" made of 1/2" (or less) steel inflict a 20 degree bend on a drawbar that stout? At a minimum, the lift pins should have been literally torn out of the yard box long before such a degree of damage could be inflicted on the drawbar.

So to respond to your question, yes. I can't think of a thing internal to the lift system that is stronger than than the drawbar. It's then almost a certainty that you've also incurred some internal mechanical damage.

//greg//

 

[Paddy]

Greg,

As you can imagine I was shocked that the draw bar would/could be bent by the 3PH and yard box. The yard box has a new shape but, not as bad I would expect!

Now with regards to the by pass valve. Is this type of valve able to divert the hydro flow for hours on end with this type of load mid stroke? Chip and I discissed this and if I understood him correctly, it should divert just fine. Maybe the spring in the valve lost its set for the long duration.

If the valve is not so expensive, it shure seams like a good place to start. I'm running out of ideas.

Thanks for your help

Patrick

 

[bluechip]

PR valve is for short term overpressure releif. extended running with PR valve "deployed" could damage the valve and or pump. Check and be sure the loader can still pick the front wheels off the ground. not real scientific, but a quick check of pump pressure. I'm thinking hte pump will be OK and the PR valve in the lift is bypassing, perhaps "bumping" the loader takes enough load off the valve that it closes breifly and allow the lift to raise. Now if your cams are out of adjustment, you could be getting a lift command beyond the range of travel which again will pop the PR and the process starts over.

 

[Paddy]

Well I have not tried to lift the front of the tractor but FEL lifts full buckets of dirt as well as it has in the past.

I will be calling monday to order a replacement PR valve.

I still need to find out the procedure for the Draft adjustment. If any one has taken a photo of the view from under the cover, it would get me in the ball park.

Thanks

 

[Brad_Blazer]

On my KM554, the drawbar is 1" thick, 2.5" wide, and protrudes 14" from it's frame. The 3ph is rated at 2068lb. The end of the drawbar is inside the ends of the lower arms so it should beat the rated load a little. A 2068 lb load on the end of the drawbar will produce 69,485psi of bending stress. If the draw bar is cold rolled steel it's yield stress is probably less than 40,000psi so it will bend. That is not to say that ugly interference between an implement and the drawbar will not damage the 3ph. It is simply no surprise that you bent the drawbar.
Even though it's a big hunk of steel, it is cantilevered and the load was applied against it's weak axis.

If it were me I would drain the lift box if necessary to look for damage. Can you take some pictures while you are at it? I just looked at the assembly in my parts manual and mine is quite different from what is shown! My parts manual shows a "lifter cylinder end assembly" that bolts to the front of the lift box and contains the relief valve and return adjustment valve. On mine the adjustment knob threads into the main casting right under the seat.

 

[Soundguy]

Prime reason why I don't loan out my tractor.... without me in the op seat

Soundguy