BH 90 issues

[bugstruck]

Having read a number of posts regarding bent dipperstick and bent bucket cylinders I thought this might be of limited use to those experiencing that problem. I haven't yet come to an understanding of what is causing the bent bucket cylinder problems but have read that the newer BH90 BH have a larger cylinder installed in an effort to mitigate that tendancy. Hope a retofit is available and works for older units experiencing that problem. I noticed a post a few weeks ago on a dipperstick cylinder that was bending and saw the mpeg?? That illustrated the actual bending of that dipperstick cylinder in a real time situtation.

Here's the bit that I noticed today on my newer BH90 that could be of limited help: The boom and dipperstick cylinder will cycle in concert as one would expect. Either direction. I.E. you can crowd or extend both at the same time. However, the boom circuit is totally defeated (either direction) on mine when the bucket cylinder is activated. I.E. you can't crowd the bucket and the main boom cylinders at the at the same time. This would noticabley limit the load on an extended dippperstick cylinder. Two cylinders, one being the larger boom cylinder, could not both pose loads on the dipperstick cylinder at the same time. It's an either/or situtation. I'm curious if the older models have that defeat on the boom cylinder activated when the bucket is in crowd operation????

If not, that may be the problem. No way is the dippersick cylinder going to take a bucktet crowd and a boom lift at the same time. Others will say it should. I don't think so. There has been allot of talk about limits on cylinders, which I frankly don't understand. I thought the limits may have to do with a cylinders operating range???? What I'm talking about is a valve limited motion that mine is implementing. Range of motion on my cylinders is not a part of what I'm observing.

We've all been strugling to understand these failures. I just wanted to throw this in the mix in the event my observations weren't noticed by others.

HTH

 

[txdon]

<font color="blue"> "...but have read that the newer BH90 BH have a larger cylinder installed in an effort to mitigate that tendency." </font>-bugstruck

Bugstruck, When did the newer model come out and how do I know if I have a newer model. Where did you read this?
Thanks for the info.

 

[bugstruck]

Been reading that up here. I think it was latter part of 2004 but I'm not sure on exactly when.

I'm too late for an edit to my first post. In my first post I stated that the boom circiut is totally defeated if you operate the bucket and attempt to operate the boom at the same time. That was incorrect. I should have said you can't crowd the bucket and raise the boom at the same time. You can in fact crowd the bucket and lower the boom at the same time. I realized that error in the post while operating today. Still the observation holds true, that you can't have two cylinders simultaneously imposing compression loads on the dipperstick cylinder at once. Not on mine at least.

This is real simple to test. I'm curious if the BH's with cylinder failures are experiencing this defeat on the boom up operation, while crowding the bucket??

 

[AntrimMan]

Bugs,
Design changes within any particular model are generally noted in terms of serial numbers. ie pertaining to models with s/n prior to blah blah blah or subsequent to ..... If one of the nice tractor dealer members might know perhaps it could be shared? There must be TSB's issued by now.
It's just not coming to me right now but I'm sitting here imagining I'm at the controls, moving the sticks with my eyes closed trying to envision what happens and the bloody dogs think I want to play.
I think each cylinder can be addressed simultaneously on my unit. I do think I can lift the boom while pulling in the dipper and curling in the bucket and swinging to the side all at the same time. I say this because I remenber, I think I remenber, noticing that the movements slowed down a bit when both sticks were used at the same time. I won't be able to confirm this untill the coming weekend. Strange how we can do things and then not be absolutely certain of the exact actions, maybe a senior moment that lasts all day? Now how about that TSB thing, any takers?
Martin