Hydraulic Thumb Question?

denick

I have a favor to ask of anyone who has a hydraulic thumb on a 200 size excavator with a quick coupler.

Could you place the thumb against the bucket, with your machine at an idle and curl the bucket very lightly with your small finger. does the thumb cylinder collapse with no real sign of resistance?

I'd appreciate your help. What brand excavator and what year? what brand thumb? what brand coupler?

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Nick

"Every day I remind myself that my inner and outer life are based on the labors of other men, living and dead, and that I must exert myself in order to give in the same measure as I have received and am still receiving" Albert Einstein

cexcavation

Denick,

I don't have a 200 size machine, but I am pretty sure that most machines have an accumulator. My hoe will do the same thing to a point I believe. It definately has resistance enough to pick up logs, rocks, etc. but the bucket has the advantage in power in order to push fluid into the accumulator when forced at idle or otherwise. Don't know if that helps or is what you are actually asking. The biggest question is has your machine always done this, or is this a new thing. If it's new then obviously something's up, otherwise it sounds normal to me.

cexcavation

I want to withdraw my previous statement I try to overpower my thumb with my bucket and no can do. I am thinking of when I roll another bucket up for transport and I let the thumb "bleed back" as I roll. It sounds like you have a thumb valve that isn't fully closing. Good luck.

Blas

Our 225 will over power the thumb for half the distance of the thumb travel and then it stops. It was like that when we purchased it brand new and has remained the same to this day. However we recently rented a 330 cat with about 2000 hours that seemed to push back a little harder against the bucket I would say it was 1/4 the travel distance of the thumb. Our 225 thumb will not collapse if the trigger is engaged and the bucket is curling in. Don't know if this is helpful.

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"It is what it is"

tgeb

The thumb on my 435 will give a few inches if you push it, but not like anything you have going on. Definitely a seal/valve problem.

Has it always been this way?

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Tom

www.gebcon.com