L35 Loader Bucket Flop

[cheekme]

Looking for anyone who has had experience or knowledge of bleeding air from the bucket circuit on an L35. My machine was built in 1999. It has about 900 hrs. and the bucket flops badly when trying to backdrag. I don't have a service manual but I believe there is an air bleed fitting somewhere on the valve.

 

[Tags]

Cheekme,
I owned an L35 for a while and I think I know what you are talking about. If you push the loader controll all the way to the left to dump the bucket with a load in it, the weight of the load forces the fluid out of the cylinders faster than the hydraylics can compensate for, so if you immediately put the bucket down to backdrag what you've just dumped the bucket will "flop" forward. There are basically 2 solutions to this, 1, when dumping the bucket do not push it all the way to the left, just partially, this slows the hydraulic fluid down from rushing out of the cylinders, it will dump slower but you will maintain pressure to the bucket. 2, you can dump the bucket by pushing the lever to the extreme left , but hold it there until the hydraulics have a chance to "catch up" , you will hear the hydraulics strain a bit, when you hear that you will have pressure to the bucket. I would usually do the latter of the two, but I would also keep the rpm's up so that the hydraulic pumps would move the fluid along a bit faster. I have also run other machines that do the same thing, so it isn't a problem, it is just a way to let the bucket dump faster. Hope this helps.

 

[Deerlope]

Do search for "3 way/ 4 way valve" I had the same problem and my question was answered very will by someone who works for Kutboa.

 

[cheekme]

Thanks Tags and Deerlop for your feedback. I'm famaliar with the overrunning hydraulics with a loaded bucket but my machine has this problem if you just start it up and immediately try to backdrag. In this situation the bucket cylinders should have oil on the head and stay firm with any backdrag load. I still believe I have entrained air because of the problem being there everytime I backdrag. I'll do the valve search and see what comes up.

Thanks again for your comments

 

[cheekme]

I'm going to try your suggestion today. I found the discussion on the 3-way and 4-way valves. I get into the regen rapid dump mode a lot so maybe that is most of my problem but we'll see.

Mike

 

[JacknCoke]

Cheekme I would agree with TAGS and you should try what he has suggested. If that does not work you might want to check the bucket pins and bushings for excessive play.
The hyd system is a self bleeding system so there is no way to manually bleed it other than cracking a fitting on the cylinder, and that will probably just get you HURT or covered in hyd oil.(not fun I've been there).


J.D.

 

[cheekme]

You have it right Tags. I guess I never really tried to backdrag before dumping. When I tried backdragging with a cold machine it was solid as a rock. Cylinder voiding is the technical description of this problem. Unless you restrict the flow of oil to keep the head end of the cylinder filled, voiding will happen.

At least I know how to manage it now although I thought the regen dump spool in the control valve would keep the head (base) end of the cylinder full and prevent the voiding. I guess not. I'm sure my Long 4 in 1 bucket doesn't help. It is heavier than the std. Kubota bkt.

Thanks for everyone's help.
Mike