621B cushion hitch

[TimHay]

I just bought a pair of 621B. Love-em, but on one of them the cushion was working fine but it now wont pick up loaded or empty. I pushed the bowl down and drive the tractor ahead it will come up. As soon as i pick the bowl up it goes down.
the operater who ran it last for me wouldnt use it. It worked fine before then and now it dont.
could he hurt any thing other than mabey his back? lol

 

[powerjoke]

nah he wont hurt anything, Cushion hitch is an option anyway's,

I believe there is a nitrogen charge that it uses to dampen hydraulic flow but if it wont pick up I would suppose it would be more of a hydro problem

Pj

 

[alan627b]

Back bothering you?

There are adjustments to the hitch ride height, both upper and lower limits, as well as the nitrogen charge. Usually if the nitrogen charge is low, the hitch will rise but still ride like a stiffneck, i.e., no cushioning effect.
A weak pump will cause the hitch to rise slowly too. If this system has a pressure relief that bleeds too soon, that will contribute too.
I'm not a mechanic, I've just seen what the mechanics do when I've asked them to fix this problem.
If the little leaf spring on the other side of the hitch is weak, or the linkage between it and the rest of the cushion hitch system is worn, this will contribute to the problem as well.
Service manual will have the service procedures in it. If you don't have them, they can be found on Ebay, or can still be bought new from the Cat dealer.
They aren't cheap though, so be prepared...
Running the scraper this way, unless you have the hitch in lockdown, might bang the hell out of the components attached to the hitch area, as when it does rise and then violently slams back down!
Hope this helps,
Alan627b

 

[TimHay]

thak you guys it helps alot
I have tried to manully adjust the plunger at the bottem that cylender but still nothing
You are right alan627b it does slam alot in the on position
I have union tractor comming out friday to look at it so thankyou
I will post the solution in case some else has the problem

 

[powerjoke]

how did the hitch repair turnout?

Pj

 

[TimHay]

sorry i took so long to reply folks
there is a valve bobody on the side of the hitch and it needed to be rebuilt.
we started to swap parts from one scraper to the other (pump and a another valve)
but it was the big one one the right side of the hitch
thank you for your help and concern
Tim