Boom bounce

[Tradesman]

Recently I have had a hard time to keep the boom from bouncing when I am doing a lot of booming down with a lot of boom out. I can control it if I boom down really carefully or full stroke, I have all kinds of pressure, I have tried throttle up and down up is better, I did change the high pressure filter recently. Any ideas
Thanks in advance
Glen

 

[Knepptune]

I'd bet it's your holding valve. Almost like a chatter?

 

[Tradesman]

I don't notice any noise unless I keep going and the boom will start bouncing. is there a way to check the holding valve ?

 

[td25c]

Noticed that on my Grove when the boom is all jammed out .

I figured it was a combination of partly engaging the boom lever combined with some boom flex that get's the bounce rhythm started ?

Like driving on a washboard gravel road , do ya speed up or slow down for an easier ride ?

If I feather the lever she calms down .

No chatter or hydro noise in my case . Just a slight boom bounce when booming down .

I test the holding valve by shutting the engine down & push forward on the lever opening the hydro circuit .

 

[catskinner 10]

SOP on a Terex
Tom

 

[Tradesman]

Noticed that on my Grove when the boom is all jammed out .

I figured it was a combination of partly engaging the boom lever combined with some boom flex that get's the bounce rhythm started ?

Like driving on a washboard gravel road , do ya speed up or slow down for an easier ride ?

If I feather the lever she calms down .

No chatter or hydro noise in my case . Just a slight boom bounce when booming down .

Exactly what I've got going on. I'm not sure but I have noticed it more lately it could be because around three weeks ago I was booming in and out about fifty feet setting 50 lb. trusses on a super hot day so now every time I get in its all I can think about hoping there isn't something wrong. I can't check my valve like you said I have electric over hydraulic pilot controls.
Thanks though

 

[Tradesman]

sop on a terex
tom

sop ?

 

[catskinner 10]

sop ?

Standard Operating Procedure.

Terex booms are like operating a Fly Rod
Tom

 

[Knepptune]

Chatter as in kinda chattering on the way down. No sound other then the boom bouncing. Basically the holding valve spring is sticky/worn and instead of opening and staying the right amount of open, it builds pressure, opens, spring shuts it, builds pressure opens. Vicious cycle and if you let it get to bad it'll really p you off on a truss job. If it only does it on boom down I'll just about guarantee its your holding valve. And I don't know of anyway to test it for that.

 

[Knepptune]

Is this boom in and out or boom up and down? If it's bouncing when your running the boom in you need your retract and extend cables tightened.

 

[Tradesman]

Chatter as in kinda chattering on the way down. No sound other then the boom bouncing. Basically the holding valve spring is sticky/worn and instead of opening and staying the right amount of open, it builds pressure, opens, spring shuts it, builds pressure opens. Vicious cycle and if you let it get to bad it'll really p you off on a truss job. If it only does it on boom down I'll just about guarantee its your holding valve. And I don't know of anyway to test it for that.

Is it a big ticket item?
Do you rebuild or replace and are they screw out old and screw in new

 

[Knepptune]

Last one I bought was $180 or so from grove. Unscrew it from the block on the bottom on the bottom of the cylinder and put the new one in. PUT YOUR BOOM IN THE BOOM STAND. You pop that holding out and the booms coming down. Takes about 10 min to install it.

 

[Tradesman]

Is this boom in and out or boom up and down? If it's bouncing when your running the boom in you need your retract and extend cables tightened.

Booming up and down. I seem to have been on a run of jobs where I had to change radius a lot like picking up at pile at 25 ft. Radius and setting down at maybe 60 ft. I notice it most with a very light load

 

[Tradesman]

Last one I bought was $180 or so from grove. Unscrew it from the block on the bottom on the bottom of the cylinder and put the new one in. PUT YOUR BOOM IN THE BOOM STAND. You pop that holding out and the booms coming down. Takes about 10 min to install it.

Looks like a reasonable place to start, I think I'll call the shop tomorrow and get things started.
Thanks

 

[Knepptune]

pricing can vary and there's no warrenty on free advice. Lol

45t grove holding valve. $180. 17t terex boom truck $450.

 

[Tradesman]

Going into a bouncing fit on a job at best makes me look bad at worst something could go bad.
Don't worry about the warranty on the free advice I'm a big boy and own my own choices .

 

[lantraxco]

If it's smoother with a heavy load on it, my money's on the load valve as Knepptune sez... could also be the cylinder itself chattering, if a new load valve doesn't cure it completely add a jar of CAT hydraulic additive, cures slip-stick in cylinder seals.

 

[Tradesman]

Ordered a holding valve $ 480.00 but $75 is shipping and about $100 is exchange. Could have got one for a manitex for $180. I talked to three different mechanics two said likely holding valve one said don't waste your money on one, so with that and your good advice I've got one coming. It's real hard to look like a pro with the boom bouncing up and down, and I do all I can to put myself out ahead of some of my competition, I won't go to the city to work and that leaves a limited market to draw from, so impressing my new customers with top professional service is how I hope to gain clients.

 

[Knepptune]

Won't go to the city. Heck that's most of our work. There's money in the city. Lol

I don't know for sure that holding valve is your problem but I do know for sure that a bad holding valve will do exactly what your truck is doing. I sure hope that fixes your problem.

 

[Knepptune]

Did you ever get your new holding valve installed?