Loader Need advice, LA450S Bucket Hydraulics

[BillCT]

We have an L300DT tractor with an LA450S Bucket in the club I belong to and are having problems with the up hydraulics on the bucket. It won't hardly lift any weight unless the engine is reved quite a bit and when it does lift it gradually sinks, so you have to constantly try and raise it. The handle on the control is pretty sloppy and seems to have this sweet spot you have to get it into before anything at all will happen. Dumping and curling the bucket works just fine even when trying to dig into a bank to get some fill, it just won't lift it.
This has allot of use over the years, the pump has been replaced a couple of times. The three point hitch hydraulics work fine.

I ran across Messick"s site that sells parts for these valves and wondering if you guys think it's a seal or something that might be worn out in there. The valve has never been apart.

Pic of valve attached.........I hope.....

Thanks,

Bill

 

[Dave M7040]

We have an L300DT tractor with an LA450S Bucket in the club I belong to and are having problems with the up hydraulics on the bucket. It won't hardly lift any weight unless the engine is reved quite a bit and when it does lift it gradually sinks, so you have to constantly try and raise it. The handle on the control is pretty sloppy and seems to have this sweet spot you have to get it into before anything at all will happen. Dumping and curling the bucket works just fine even when trying to dig into a bank to get some fill, it just won't lift it.
This has allot of use over the years, the pump has been replaced a couple of times. The three point hitch hydraulics work fine.

I ran across Messick"s site that sells parts for these valves and wondering if you guys think it's a seal or something that might be worn out in there. The valve has never been apart.

Pic of valve attached.........I hope.....

Thanks,

Bill

To narrow down where the problem lies, swap the lift arm and bucket hoses at the loader valve and see if the problem moves or remains the same..

Hydraulic valves are manufactured to tolerances the normal person could not even measure. The valve design relies on the tiny clearance between the spool and valve bore to control leakage.

There are no seals inside the valve.

To identify the problem within a cylinder follow the attached test procedure.

Dave M7040

 

[BillCT]

Thanks very much for the quick reply and information, I'll do as you suggested.

So from what you're saying if the problem turns out to be the valve there's not much that can be done to repair it?

Bill

 

[Roadworthy]

If defective the valve may be repairable but it is not something and individual has the tools to do. The problem is quite possibly with the lifting rams, though. Check out his pdf file to test those.

 

[Dave M7040]

Thanks very much for the quick reply and information, I'll do as you suggested.

So from what you're saying if the problem turns out to be the valve there's not much that can be done to repair it?

Bill

The only repairable part of the valve would be the external parts such as those providing a Float position. Usually in a cap bolted to the outside of the valve body.

The clearances I mentioned earlier (between a spool and valve body) fall between 0.0001 & 0.0003"

This is a factor of 10 smaller than any feeler blade you can buy.

Dave M7040

 

[JWR]

The best tools for debugging this are pressure gauges. Most tractor dealers have a set of gauges made up with stubs of short lines and connectors that can be temporarily put in-line to see where you have and do not have adequate pressure. If you can get access to gauges (or have a shop debug for you) that will tell you where the problem is.

Dave is the great experience helper among us and certainly follow his directions. However, I do disagree with Dave about there being no seals in the loader valves. I'm sure it varies but the Nimco loader valve on my MF 2660 had O-rings that were common offenders and believed to be absorbing fluid. My dealer rebuilt the valve with new different material seals installed and cured some problems with mine.

You sound like the machine has high hours and probably lots of wear. As Dave suggested, swap those lines and see if the problem moves which is your easiest first trial.

 

[BillCT]

The best tools for debugging this are pressure gauges. Most tractor dealers have a set of gauges made up with stubs of short lines and connectors that can be temporarily put in-line to see where you have and do not have adequate pressure. If you can get access to gauges (or have a shop debug for you) that will tell you where the problem is.

Dave is the great experience helper among us and certainly follow his directions. However, I do disagree with Dave about there being no seals in the loader valves. I'm sure it varies but the Nimco loader valve on my MF 2660 had O-rings that were common offenders and believed to be absorbing fluid. My dealer rebuilt the valve with new different material seals installed and cured some problems with mine.

You sound like the machine has high hours and probably lots of wear. As Dave suggested, swap those lines and see if the problem moves which is your easiest first trial.

Sorry.........I didn't get a notification and didn't realize you had replied. Thanks, good idea on the gauges, we may try that also to verify the results.

I did the swap test and found now the bucket has no power so it looks like there's something in that portion of the valve. Wonder if it's worthwhile rebuilding this or getting a new one. There's a terrific amount of slop in this thing, it's been used and abused over the years.

Does anyone make a good replacement that'll fit or do we need to go to the dealer and bend over?

 

[JWR]

If I were you I'd pull off the loader valve and take it to any good hydraulics shop and ask if they can rebuild it. If that is prohibitively expensive OR they can't, then shop around for a replacement valve. I had an Amish welding shop in NE PA put one on a B2150 when adding a loader for me -- it was simple works great, not expensive. I do not know the separate price for the loader valve but the whole job was so reasonable it could not have been real high. A large shop like Wengers of Myerstown in NE PA can probably price one for you and might even have serviceable ones used in stock. They pointed me to the Amish welding shop near them years ago. Wengers tends to be very knowledgeable and willing to talk about such things on the phone. They run a large salvage business among other things as well as selling some new equipment.

 

[BillCT]

If I were you I'd pull off the loader valve and take it to any good hydraulics shop and ask if they can rebuild it. If that is prohibitively expensive OR they can't, then shop around for a replacement valve. I had an Amish welding shop in NE PA put one on a B2150 when adding a loader for me -- it was simple works great, not expensive. I do not know the separate price for the loader valve but the whole job was so reasonable it could not have been real high. A large shop like Wengers of Myerstown in NE PA can probably price one for you and might even have serviceable ones used in stock. They pointed me to the Amish welding shop near them years ago. Wengers tends to be very knowledgeable and willing to talk about such things on the phone. They run a large salvage business among other things as well as selling some new equipment.

Great. Thanks very much, will do.

Bill