Bump up lift capacity of L3400/LA463 Loader

jfay · Jan 3, 2009

Ok, so I have an L3300 which is pretty much the same tractor and decided to check the hydraulic pressure and see if it needs a boost. I put together a pressure guage from Northern Tools and connected it to a spare male tip so I could use my remotes to measure the pressure. Got around 2100 psi, so I decided to go for the increase. I hooked up my shop vac to the hydraulic oil filler to prevent any fluid from spilling and turned it on. Took a 7/8 inch socket wrench and removed the left hand plug (when looking up from underneath the right side of the tractor).

jfay · Jan 3, 2009

OK, back to the upgrade. I pulled out the plug and spring assembly. The upper part had to be pulled out with a pick as the vacuum from the shop vac was keeping it in, although it isn't necessary to remove it. I put things out on the bench and measured the existing shim located below the spring. It was a single shim of .2 mm width. I purchased a #10 washer at the local hardware store for pennies. The actual dimension of the shim matches a 6mm washer perfectly, but either will do. The washer was 1.2 mm thick, so I removed the existing shim and used only the single washer. I put it all back together and torqued the plug to 45 ft lbs and started her up. Got around 2500 psi, which I am quite happy with and will see how it works out before making any other changes. Pictures show before and after pressure. A 400 psi increase with a net increase in shim size of 1 mm seems to be consistent with the manual which shows 38 psi per 0.1 mm.

This is an easy job for anyone. Go to it!!

Goog · Jan 3, 2009

Good pictures and instructions. I think you will be pleased with the results. You did good at hitting 2500 psi on the first try. Brian

canoetrpr · Jan 4, 2009

Interesting thread. Thanks for posting. My loader has been plenty capable but it is nice to know that I could add a bit more oomph if I added a quick attach bracket which would take up around 100 lb.

BTW. How much hyd fluid should one expect to loose while mucking with the relief valve and shims?

Goog · Jan 4, 2009

When I did mine I made sure I had a clean container to catch the lost fluid in. I used a plastic dish pan. I also cleaned the area of the relief valve first so no contaminents would get in the lost fluid.
When I removed the relief valve at first there is kind of a splash and then it settles in to a constant stream. After measuring shims/washers and trying three different times I probably had a couple gallons in my container which I poured right back in the tractor. Hope this helps. Brian

jfay · Jan 4, 2009

Canoetrpr: You literally won't lose a drop of hydraulic fluid if you put a shop vac on the fill port for the hydraulic fluid. The air gets sucked into the relief valve rather than fluid pouring out. You don't get any in the shop vac as it is way above the fluid level. Saves making a mess.

Harvest Moon · Jan 4, 2009

Any one with the LA463 notice any affect of higher pressure on the smoothness or jerkiness of your position control?

Harvest Moon · Jan 9, 2009

Can any of you who have made this change tell me how substantial that spring is? Does it take 2000 lbs. to compress it or could you compress it with your hands, even small amount?

It seems like common sense that before the relief can open 2500 psi would need to be applied to it but I wanted to confirm that it works like I would expect. It looks like it would have somewhere near 1 sq.in. of surface area to correspond to the psi.

jfay · Jan 10, 2009

Harvest Moon:
As i recall the spring is not that strong. You could compress it some with your fingers.

jimainiac · Jan 10, 2009

jfay, thanks for posting those pictures. I'm trying to psych myself up to attempt to check the pressure and possibly increase the pressure for the loader. Our tractor is an L3830, so it might be a little different as to the location of the relief valve, but the procedure is probably about the same. I have the shop manual, but it doesn't go into great detail. I'm really intrigued by the shopvac method of holding the hydraulic oil in place. I just don't understand how you can put the suction hose in the filler without sucking out the fluid? Do you have to regulate the intake of the hose? Obviously you don't want too little suction, but what if you have too much? Is there a trick to it?
To tell the truth, I already got off to a bit of a false start on the project. First thing to do is check the pressure, and I found a gauge lying around the workshop. I rigged it up like in the pictures and attached it to the rear remote. I hopped up on the tractor, fired it up, looked back to the gauge and actuated the remote valve (for the first time, as I don't have any attachments that use it yet.) Kablooie! One small mistake - didn't pay attention that the gauge was 0 - 100 psi. Maybe I shouldn't be allowed near a tractor...