BL25R FEL Operation Question

boggie81 · Oct 25, 2020

LouNY said:
It's a possibility,
but some valves will let the bucket dump down faster than the fluid volume can accommodate and it can cause the issue you are having.
I have heard several explanations of that theory and they don't seem plausibility to me but I have been told that was why some valves have a regenerative dump feather.

I got a chance to try curling the bucket and lifting the tractor off the ground.
I left it off the ground and went back 3hrs later, still had the tires off the ground.
Wasn't quite as far off the ground but still off the ground.

LouNY · Oct 25, 2020

It looks like it holds it is still possible that one of the cylinders is bypassing a bit but it does look god.
If you slowly curl the bucket does it still have the floppy bucket.
Sorry I don't have a help full answer for you.

K5lwq · Oct 25, 2020

Air is getting into the system causing your symptoms. Seeing as Slim has the same loader and does not have that issue, I would look closely at the rubber lines feeding the pump. My bet is there is a leak on the suction side of the system.

52wej · Oct 25, 2020

My 16 year old Century 2535 (Branson 3510 equivalent) will always dump a load faster than the valve will drop it. But after dumping the load while holding the valve in the dump position the system will catch up like you described. Once the pressure is on the dump side it will hold the tractor off the ground as shown in the picture. And this is a tractor with over 1300 hours on it. It is probably something in the valve design, but it has never been a problem for me. If I am back dragging, even in float position I make sure that the pressure is on the drop side. That usually takes a second or three to catch up. W. Jones

Asteral · Oct 28, 2020

the most common place your going to find an air suction leak on a branson is going to be at the large low pressure rubber hose on top of on the side of the hydraulic pumps, and more often that not its being caused by the hose clamps being used to secure it to the tractor, if they are put on to tight over time they will wear into the hose from friction and movement, creating a small crack that allows air to suck into the hydraulic system, i would check here first if i had this in our shop.

boggie81 · Oct 28, 2020

Thanks everyone for all the input and suggestions. As soon as i get a chance ill check out the pump and see if i can see if it is sucking air from somewhere.

boggie81 · Dec 17, 2020

Asteral said:
the most common place your going to find an air suction leak on a branson is going to be at the large low pressure rubber hose on top of on the side of the hydraulic pumps, and more often that not its being caused by the hose clamps being used to secure it to the tractor, if they are put on to tight over time they will wear into the hose from friction and movement, creating a small crack that allows air to suck into the hydraulic system, i would check here first if i had this in our shop.

I finally got around to looking at the hoses. I didn't see any visible issues. Is it usually noticeable or would I have to pull the line to check?

Asteral · Dec 18, 2020

sometimes it's visible easy to see, but sometimes we have to take the line off and do a visual inspection, but from what i've seen in the past the most common leak is going to be around that hose on the back side facing the engine, like i said in my last post its usually around the hose clamps for the low pressure return line on the hydraulic pump, but i have also seen the same thing occur and the small hose section that connects your hydraulic transmission filter housing to the hydraulic system. so i would check there next if you haven't found anything on the first hose.

Bavarian · Dec 18, 2020

LouNY said:
It's a possibility,
but some valves will let the bucket dump down faster than the fluid volume can accommodate and it can cause the issue you are having.
I have heard several explanations of that theory and they don't seem plausibility to me but I have been told that was why some valves have a regenerative dump feather.

You're right. Old excavators had the very same problems. There is a fix for it. There needs to be a restiction put in the hydrauluc line. This prevents gravity taking over and pull the cylinders out and create a vacuum.
There are adjustable valves with free return flow available. A good hydraulic shop should have them.

ericm979 · Dec 18, 2020

I put an adjustable one way restrictor on the dump circuit. It reduces "bucket flop" when set right, but the bucket still moves some when back dragging. I'm leery of back dragging too hard and damaging the loader so it's not that big a deal for me.