What's new
What's new

Hitachi Seiki ht20 hydraulic pump

linmach22

Aluminum
Joined
Jun 24, 2023
Location
TEXAS
I have a 1990 Hitachi Seiki ht20 sII and I have had a issue with chuck clamp unclamp and my contactor will shut the hydraulic motor off. Now when it works if I use the chuck and tailstock the turret will unclamp on cuts or won't toolchange. Do I need a new hydraulic pump motor? I need help asap thank you!
 
If the contactor is going out on overload? (not being shut off by the machine itself).......then you need a clamp amp meter to actually test the motor amps while running.
Could be the motor failing, could be a weak overload.......
Might be as simple as a poor wire connection/s somewhere in the motor circuit........
Or the contactor itself has burned contacts causing higher amperage......
Need to verify overload is set higher than motor running amps.....
All of the above need verified before moving forward........
 
The contactor is good and I increased the amp before tripping and now it stays running but sometimes the chuck won't open and close and it still will pop tool out of position and alarm when I use the tailstock unless I put the pressure at about 10pounds the it will run the tool but won't always allow a tool change. Thank you for your assistance I greatly appreciate it! I am going to go get a clamp amp meter and check that as well any other suggestions?
 
I cleaned the tank and replaced the filter last month when I had my first issue with it. It is supposed to be at 500psi but it's only showing 400psi it is consistent. It also has a kinda whining noise when I clamp/unclamp chuck and bring tailstock in and out. Could air in the lines cause these issues? I am fairly new to working on hydraulic systems.
 
If it is the commonly used Vickers style variable displacement pump, air in the lines makes a loud intermittent growly noise. If it cannot make full pressure despite adjusting the pump, then pump wear or malfunction may be the trouble.
 
I just bled the lines again to be sure and dropped my chuck pressure to 200 and no more growling whining noise. It has a leeson pump motor on it. I am going to try and run a couple parts to see if the problem persist and see if the pump motor doesn't get hot. Before once it's been on for a few hours the pump motor did feel hot.
 
I just bled the lines again to be sure and dropped my chuck pressure to 200 and no more growling whining noise. It has a leeson pump motor on it. I am going to try and run a couple parts to see if the problem persist and see if the pump motor doesn't get hot. Before once it's been on for a few hours the pump motor did feel hot.
It's going to feel hot. The question Is whether or not It's too hot. Can you leave your hand on it? Or is it too hot to touch? If you cant leave your hand on it. I'd say that's definitely too hot.
 
It's going to feel hot. The question Is whether or not It's too hot. Can you leave your hand on it? Or is it too hot to touch? If you cant leave your hand on it. I'd say that's definitely too hot.
Before I couldn't leave my hand on it because it was too hot. It's only been on about 30minutes and it's warm but not hot.
 
If it is the commonly used Vickers style variable displacement pump, air in the lines makes a loud intermittent growly noise. If it cannot make full pressure despite adjusting the pump, then pump wear or malfunction may be the trouble.
It already did it again with my part off tool it popped the tool out of position and alarmed out but now it's not even using the tailstock.
 
If It's the pump that's running that hot and you keep having problems, I'm betting It's a pump problem.
 
If It's the pump that's running that hot and you keep having problems, I'm betting It's a pump problem.
That was my assumption because I've checked everything but the amps while running. Do you know where I can get a replacement pump? I've tried finding one without much luck for the same kind
 
I have had no luck I've called a bunch of places and nothing. Does anyone know what motor I may be able to put in instead of the original?
 
cyber did not have anything?
Post a picture of the motor nameplate, the label on the motor itself...
Without checking the actual amps of the motor you are just gambling that it is the motor/pump.
Have you actually checked the entire electrical system from the contactor to the pump?
Actually verified all connections including the wires at the motor.?
It's your money, but it would stink buying a pump and it does the same thing..... :wrong:
Re-reading your posts....It aint rocket science, pull the motor/pump off the tank and pull the pump cover off and look.
full of scratches?? shiny clean?? Id verify the suction piping or whatever is used on the suction side of the pump for leaks cracks etc.
 
Last edited:








 
Back
Top