raise and lower cab

[Suprman]

It folds out and goes past straight. If you push on the cab it’s as locked as it gets. If your pivot is stuck then it won’t work right.

 

[m-35tom]

The one in your picture has not gone past straight which is what I am asking about. It is not locked yet.

 

[Suprman]

I can take another tomorrow that’s the only one I had on hand

 

[Smike740]

I have seen the whole oblong assembly installed backwards. View attachment 754405You can see bottom right of the pic the lock arm is fully open.

This is all the further mine goes up as well, and my hydraulics are working fine. I believe the cab weight is over center at this point since the cab will not go down on it’s own until it lowered quite a bit from this point.

 

[Floridianson]

Yep Smike740 that is as far as mine goes too. Never tried to force it to lock because as you said cab weight seems to hold it well enough for me.

 

[m-35tom]

There is something about the part on top of the cab cylinder that either does not work or is not understood. The users manual does not cover how it works, but it would not be shaped the way it is if it had not been intended to do something to allow the cab to open further.

 

[Ronmar]

Looking at the 24P manual page 254 you will see part #4 is supposed to slide around in the rod end. Chapter 19 in the -20 manuals(page 19-49) shows these component interactions a little better. Part #4 on mine appears to be stuck in place at the bottom of the slotted rod end. There are flats on its end plate but I need to find a wrench big enough to apply some torque to it. Since it doesn’t have a dust boot, it may also be full of sand and gravel...

I got mine freed up. It was stuck at the bottom of the rod end fitting. The cab would raise past the balance point but would not fully unfold/straiten the folding stop bar. I Loosened nut/bolt, added oil, still didn’t move. Noticed it had a little bit of slop right as it reached the cab balance point. With it stopped at that point, I was able to rock the cab back and forth by pushing on the cab with my hand. I was able to grab across the flats of that sliding part #4(its called a control cam) with a pair of channel lock pliers and rotate it into line with the long groove in the rod end.


When I did this the cab rotated to the full open position with the folding stop fully extended.


When freed-up the only thing restraining the cab as it passes over the balance point is the friction created by part#5(spring washer) and the clamping force provided by the bolt torque of 180-232FT/LB... With the bolt loosened the cab lurches several inches. It was not particularly fast or violent, but it was a surprise


I am guessing this feature was to allow some freedom of movement and not stress the hydraulic cylinder and its mounts when the cab is lowered and riding/bouncing on the air suspension...


Tomorrow I will flush it again and pack it with grease and re-torque the bolt...

 

[coachgeo]

thanks for manual page info.

he solved his problem.... see here. https://www.steelsoldiers.com/showthread.php?184760-Opening-Cab

 

[Ronmar]

Ok interesting result this morning. Greased the control cam and inside the rod end and cycled it in the rod end a bunch then wiped off what grease was squeezed out.


I Re-torqued the nut and bolt and lowered the cab. When I went to raise the cab again the cam rotated in the rounded portion of the rod end during the lift and re-assumed its former position stopping just over the balance point. I repeated this a few times and it did the same thing every time. One thing I noticed is that the cam re-aligns with the long slot in the rod end when the cab is fully lowered.


I think this is by design. I,think the control cam and the rod end form a dual function rod end. At the bottom it is a sliding rod end so the movements of the cab riding on the air suspension is not transmitted into the hydraulic cylinder or mounting structure. When the cab fully lowers and the air shocks inflate to take the weight, you can watch the cab lift off of and unload the hydraulic cylinder as the control cam slides in the long slot.


As you lift the cab, the load on the rotating control cam causes it to rotate in the larger bottom section of the rod end and turns it back into a fixed rod end by the time it reaches the top of the stroke. This gives smooth operation across the balance point at the top.


Having watched the transition across the balance point a few times with the rod end cam in sliding mode, it is a little disconcerting to see the cab lurch that much as it falls across the balance point.

I also dont think those folding arms are a lock. Having closed the cab several times with them fully extended, they gave no hint of resistance whatsoever to closing the cab when fully extended. I think they are only intended to limit the cabs maximum opening point...

 

[m-35tom]

My cab will not close until I push the bar back past the straight position. But I agree to be a lock it should go a little over center.

 

[Ronmar]

Well the operators manual dosnt say anything about releasing a lock to lower the cab...