Basic information on hydraulic repair?

[Wendi]

Hello, do you know where I can find basic information on repairing hydraulics? I recently purchased a new TYM T450 with a LT400 loader and after 150 hours several of the fittings around the loader's directional control valve are leaking. Even though I'm hoping the dealer will take care of this problem, since it is still under warranty, I would like to know more about the proper procedures for working on hydraulic components.

 

[Grrrr]

Hello, do you know where I can find basic information on repairing hydraulics? I recently purchased a new TYM T450 with a LT400 loader and after 150 hours several of the fittings around the loader's directional control valve are leaking. Even though I'm hoping the dealer will take care of this problem, since it is still under warranty, I would like to know more about the proper procedures for working on hydraulic components.

Is it just that the pipes have become slightly undone or are their seals leaking? Some more information would help in diagnosing the problem. Maybe some pics?

 

[froggy]

Try this site:

Basic Hydraulics

 

[kennyd]

Here is a 173 page Army Manual

 

[Wendi]

I think it may be both. I'll try to post a jpeg image of the control unit that shows some of the leakage. At first the leaks appeared to be coming from ports connected to the joystick controls (the brass cylinders). Now more fluid is leaking from one of the hoses that connects to the tractor hydraulics. That hose appears to be a replacement and not an original part. Could it be possible that the replacement hose assembly is a two part construction while the others (originals) are of solid construction?

 

[Wendi]

Here is the image of the control unit. ( I hope I have attached the image correctly!) At first the fluid appeared to be coming from the joystick cable attachments, but now, as I have used the hydraulics more, fluid is also coming from this replacement hose.
Thanks for recommending the manual and the website on basic hydraulics. Both look very interesting. I sure will have a lot of reading to do!

 

[hill]

Here is the image of the control unit. ( I hope I have attached the image correctly!) At first the fluid appeared to be coming from the joystick cable attachments, but now, as I have used the hydraulics more, fluid is also coming from this replacement hose.
Thanks for recommending the manual and the website on basic hydraulics. Both look very interesting. I sure will have a lot of reading to do!

If leaks are the whole problem they just need to be fixed one at a time.

The 'free' educational link posted by Froggy is based on the same Army manual posted by KennyD so the two are not as much reading as they first appears to be.

If you have a manual for the tractor, especially one that describes how to install the loader to a previously unequipped machine it might go a long way toward giving you insight into how everything works and where and what the various components are and do. anyway I found my loader manual to be very helpful in figuring out the lay of the land under the covers of my new Kubota tractor.

 

[dfkrug]

Wendi:

Looks like you have so-called "banjo" fittings, as well as some
more conventional threaded fittings. When you find which one is leaking,
make sure you follow theses sealing practices:

> for threaded fittings using pipe thread (NPT), use a paste sealant, not
teflon tape. Tape fragments mess up the internals of spool valves.
> for threaded fittings that use compression sealing (JIC), don't use any
sealant. These fittings have matching-angled surfaces. Don't over-tighten.
> for threaded fittings that have rubber o-rings (ORFS or ORB), don't
use any sealant. Replace any O-ring that is damaged.
> for banjo fittings, you have 2 copper gaskets, one on each side of
the fitting. When re-using these it is best to anneal them to restore
their softness. Heat to red with propane torch and let air cool.

BTW, your loader seems to be made by the same manuf as my
Kioti's. The FEL valve is different, however.

Good luck.

 

[6sunset6]

I think copper anneals when you quench it. Copper is the opposite of steel.
So letting copper cool slow will result in hardening. Not what you would want for seals. Just heat them up and dump in a bucket of water.

 

[dfkrug]

I think copper anneals when you quench it. Copper is the opposite of steel.
So letting copper cool slow will result in hardening. Not what you would want for seals. Just heat them up and dump in a bucket of water.

You are correct, SUNSET. I was not thinking as I typed, and it has
been a long time since I was annealing copper gaskets (fuel injection
systems). I did quench them after sanding out marks from previous use
then heating them. You seem to get work-hardening of the copper
from even one use.

 

[RonMar]

OK, Ill ask it... Have you put a wrench on the end bolt of that banjo fitting and checked to see that it is tight? It could have just worked loose... It shouldn't be white knuckle tight, but it should be snug. That also appears to be the high pressure inlet line to the valve(hydraulic safety appears to be right behind it) so it has to deal with full system pressure when you lift a heavy load on the loader.

As for anealing, I used to do that for my R5/RD head seals. I would lay them out on an electric stove burner to heat them red then shut the burner off and let them cool in place. This was the way I was taught, it worked well and I never questioned it. A friend said I should quench them but when I asked why he couldn't tell me. So a trip to the library and several metalurgy books later, we determined that it was the temperature rise above a certain level that performed the anealing process. The quench was optional... The quench appears to be pretty handy if you are using a torch to heat the seals. The shock cooling causes the scale to flake off, but the rapid cooling also tends to warp them a little bit.

 

[dfkrug]

The shock cooling causes the scale to flake off, but the rapid cooling also tends to warp them a little bit.

I remember how the scale just flew off when quenched. I also used
custom-made soft copper head gaskets on a Ferrari I used to own.
It is amazing how much it would "squish" under head bolt pressure.

Fuel injection leaks from banjo fittings was often a challenge.

 

[Ob1kubota]

Mr. Wendi welcome to the forum as a new member. I go back and read my old post from time to time so I hope you see this blog. One of the best hydraulic manuals to get you started is written by Rory McLaren at the Fuid Power Training Institute ( Announcing that Rory McLaren Fluid Power Training, Inc. (RMFPT) has now officially become "the Fluid Power Training Institute? ) Indroducton to Closed-Loop Oil System Functions. It will answer your needs and take you into a higher understanding of and appreciation for hydraulics. One of the best things I've ever done for myself was to get certified by the Fluid Power Society in several of their programs. One course in particular that will meet your above needs is the Certified Mobile Hydraulic Mechanic program. Good luck with your future projects.

 

[Wendi]

Thanks for the discussion on annealing. My husband and I have worked on quite a bit of metalworking projects: sand casting bronze and silver, lost wax casting, brazing, welding and steel fabrication and are always interested in new thoughts about the fine points. I think he said ferrous metals can be quenched and non-ferrous must air cool? I'll ask.

After communicating with the folks at TYM we think the leaking at the spool actuators and the joystick cable connections is caused by bad seals or o- rings in the directional control valve and, separately, one leak at that P banjo fitting which will need to be seated in the valve body better.

Luckily, since the tractor is still under warranty, an expert mechanic will perform the repair, which gives me some time to learn more!

Thanks for the leads on the manuals and instructions. I found some good drawings of directional control valves including one that is similar to mine at http://www.parker.com/euro_mcd/cat/english/HY17-8546-UK.pdf, mine is like pag. 22. I thought the artist did a good job communicating the basic functions of the components.

 

[Wendi]

Whoops! Got that about annealing backwards!
Non ferrous metals, such as copper, bronze should be annealed by quenching. Heat copper just until it glows medium red in dim light and quench as soon as redness disappears. To remove fire scale you can directly quench it in pickle. For copper, that's Sparex #2 (sodium bisulphate).

 

[Ob1kubota]

Whoops! Sorry Mrs. Wendi!

 

[apeak]

I have a 5040 Kubota tractor and the loader bucket is going up and down by itself. Has anybody had that trouble. How can I fix it. Im out of warrenty and locat kubota tractor dealer went out of business. apeak

 

[oldnslo]

I have a 5040 Kubota tractor and the loader bucket is going up and down by itself. Has anybody had that trouble. How can I fix it. Im out of warrenty and locat kubota tractor dealer went out of business. apeak

Is the lever on the control flopping around?

 

[J_J]

Do you mean that with no hands on, the loader operates on it's own?

Hydraulics gremlins at work here, Just kidding.

If the spring centering springs are broken and you are bouncing around on uneven ground, that might happen.

Something has to move the spools to make things work.