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Lathe losing hydraulic fluid

zschary

Aluminum
Joined
Oct 5, 2012
Location
Dallas TX
Cant seem to find what i think is a leak of hydraulic fluid into my coolant tank.. .. I found one coming through the pressure gauge replaced it finally and thought that was it.. Its going slower but i should not really be losing any of it? or does the machine go through some fluid in most cases? a week or two and its an 1/8" under the line i marked on the sight gauge.. None on floor, can't seem to find a leak in the main spindle area, so i am looking at the sub spindle and turret, but not seeing it..
are there any tricks to find a leak? thanks..
 
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theres a kit you put a dye into the tank then special glasses and a blacklight i believe will illuminate the dye so you can trace it.
 
where exactly is the seal located on most actuators, is it at the back where the hydraulic lines go in, so the work is at the back, or the chuck comes off first? I believe it to be in the draw tube assembly.. I know its machine dependent but can someone give me an idea on best way to get to the seal and what usually needs to come off.. thank you
 
It's going to be somewhere off the end of the spindle, at the far left side of the cabinet. You may need to remove sheetmetal to even see it. It should look pretty obvious: a big hydraulic slave cylinder with your hydraulic hoses going to it and probably a drain line that returns small amounts of seepage back to the hydraulic reservoir.

This is what a drawbar assembly looks like out of the spindle. I have zero experience with your particular machine but, I don't see any reason it would look much different than this:

 
it looks like that yes, curious where the seal is or seals .. Having an issue with hydraulic fluid seeping out of the end of it into the coolant. i checked the drain back which is clear.. i guess i need to open it all up to get to it?
 
We were losing hydraulic fluid on a lathe and couldn't figure where it was leaking. Customer was watching me make his part and asked "is it normal for the tailstock to squirt oil out the back?" New seals for the piston and rods.
 
There isn't much going on in the drawbar. Look up hydraulic drawbar rebuilds on YouTube to get some idea of what the guts look like. It's a piston, a cylinder, some bearings and the seals. Very basic. If that's where the fluid is coming from, the unit comes out and you rebuild or replace it.
 
If you can read the manufacturers tag on it they can provide you with a rebuild kit (o-rings and any seals). Last I checked the Kitagawa's were in the $400 range.

Brandon
 
Thanks Brandon How big a job is it? How much comes apart just for seals? thank you
If you can read the manufacturers tag on it they can provide you with a rebuild kit (o-rings and any seals). Last I checked the Kitagawa's were in the $400 range.

Brandon
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Before blindly tearing your actuator apart, check the drain housing and plumbing. Plugged or cracked drain hose can cause oil loss. Actuators leak by design. The housing catches the leakage and drains it back to the tank.
 
Have you checked all of your gauges? We had a phantom hydraulic leak that was leaking into the coolant tank only. Finally the coolant got to be so bad we pulled the tank and replaced the coolant, but while we had the tank out I noticed a oil drip on the clean floor. Turns out the pressure gauge for the tailstock quill pressure had broke, and was draining down the inside of the enclosure. After shining inside with a flashlight I could see exactly where the oil was coming from. I would agree with the dye kit first, before you start tearing into this thing too deep.
 
Its a big enough job I would want to be sure that the drawbar cylinder was the issue! Based on my experience you should be loosing the amount you are within a day or two if it was the cylinder.

As others have stated the oil dye and blacklight kit is a game changer at finding the leak. You can usually pick them up at your local auto parts store. You just need to get several vials of the dye because your hydraulic tank is probably 5 to 10 GALLONS not quarts. Just tell the person behind the counter you need an engine oil dye kit.

Purchase the blacklight to if they have it. Pour dye in the hydraulic tank and run the machine a couple of days and start looking inside you covers with the blacklight. You will see it if its a gauge or something like bigjon61 said.

Do this before pulling the drawtube cylinder and let us know what you find!!!!!!!

Brandon
 
Have you checked all of your gauges? We had a phantom hydraulic leak that was leaking into the coolant tank only. Finally the coolant got to be so bad we pulled the tank and replaced the coolant, but while we had the tank out I noticed a oil drip on the clean floor. Turns out the pressure gauge for the tailstock quill pressure had broke, and was draining down the inside of the enclosure. After shining inside with a flashlight I could see exactly where the oil was coming from. I would agree with the dye kit first, before you start tearing into this thing too deep.
yea that just happened to me.. The main pressure gauge had started leaking heavily, and drained into the bottom of the control area, and prob a bit into the coolant. like a few quarts or more .. 1000 psi gauge.. I got past that.. The back of the main spindle area is oily looking too.. I know its in there.. I found a small leak and fixed it but the oil is still going down slow.. i think it could be the draw tube seal, makes sense.. thank you
 
Its a big enough job I would want to be sure that the drawbar cylinder was the issue! Based on my experience you should be loosing the amount you are within a day or two if it was the cylinder.

As others have stated the oil dye and blacklight kit is a game changer at finding the leak. You can usually pick them up at your local auto parts store. You just need to get several vials of the dye because your hydraulic tank is probably 5 to 10 GALLONS not quarts. Just tell the person behind the counter you need an engine oil dye kit.

Purchase the blacklight to if they have it. Pour dye in the hydraulic tank and run the machine a couple of days and start looking inside you covers with the blacklight. You will see it if its a gauge or something like bigjon61 said.

Do this before pulling the drawtube cylinder and let us know what you find!!!!!!!

Brandon
now that makes sense. It would suck to go into the draw tube hydraulics, and realize later it was not the issue.. That would take me a week to get over and stop bitching about.. maybe 2..
 
Make sure if you use the dye to look all around the turret. Most of the turning centers I have been around use hydraulic to unclamp the turret before rotating.

You can also remove your chuck or collet system from the spindle nose and see if there is hydraulic fluid puddled inside the spindle shaft or drawtube.

Brandon
 
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