Hydraulic pipe bender pump problem question?

[Mr Fixit]

Hello Group,
I have a Enterpac hydraulic steel pipe bender that when I go to use it it requires a lot of little strokes to pump it up. I have checked the fluid when it is in the relaxed position or "NOT" under pressure and it seems full with the hand pump sitting on the floor level. The regular floor jack or bottle jack does not work this way, have I got a problem with this equipment? The whole system was sent out about 2yrs ago for a rebuild so the guy I got it from said. It does have a brand new hose, new paint and a new copper washer under the filler screw. I'm trying to bend some schedule 40 pipe for some hand rails and until i figure out what is wrong my arms can't take all the pumping required to do just 1 90* bend so I hope someone can help keep me from killing my arm.

TX Chris
Mr. Fixit in the Family

[wierdscience]

By little strokes,do you mean you are getting the full stroke,but it's only moving fluid and producing pressure for a small part of it?

If so it could be air in the system,if not then next thing would be the pump piston packing.

[duckman]

If its an Enerpac and its not there 2 speed pump your gonna pump your arm off, and wish that you'd have bought the air powered pump.
Wierdscience if its Enerpac they use spring return pistons if the packing is leaking you'll have a mess on the floor. OK now to bleed the pump, remove hose from cylinder it should be a quick disconnect close the valve on the pump push in the little pin that sticks out of the quick conn. slowly pump the handle you should get oil if not pump until you do release pin, put back together, now pump the cylinder out all the way, now the tricky part make sure the fitting on the cylinder is facing up raise the pump assembly over your head and open the release valve you may here air going back into the pump body, if you here air you've bled the system, now close the valve again and pump the handle the cylinder should instantly because there is no air in the system. Thats just my humble opinion to be taken with a grain of salt.

[JoeLee]

You could have loose packings or fluid leakage through the check valve or ball. Both would cause what your explaining since the majority of fluid would be bypassing the piston. Seen it before.

JL............................

[boslab]

do an oil change and check the spring on the non return valve on the pump, rouge bits of ptfe tape is the usual culprit
mark

[Davidhcnc]

Is it the composite or matal pump?
Either way fill it with its filler elevated.

I'd check its full of oil and check for air in the cylinder/ram


http://www.enerpac.com/files/im/hydr...ps/L1763_i.pdf pages 1-7.

[gary350]

I have several hydraulic jacks, 2 ton, 5 ton, 10 ton, 20 ton, 30 ton. The 20 ton has the problem you discribe I lift the handle all the way up them push it down but it only pumps about 1/4 of the stroke. On the down stroke of the hand pump it is free all about 3/4 of the stroke the last 1/4 of the stroke is the only part that pumps. I discovered if I lift the handle and hold the handle up at the top for 5 seconds it allows the oil to fill the pump piston then it will pump the full length of the down stroke. With the handle up suction pulls oil into the pump piston through a 1 way valve for some reason oil is moving too slow. I noticed in cold weather it is worse and hot weather it is better. None of my other jacks have this problem so it must have something to do with the one way valve that lets the oil into the pump piston not opening all the way to let oil in. I have not tried to fix my jack yet but maybe this will give you some ideas what to look for when fixing yours.

[Mr Fixit]

Hello Group,
What great answers. Weirdscience yes it is a full stroke with no pressure until the very end if at all and not consistent. Duckman you have all the answers, it is an Enterpac pump with no disconnect on the pump end but I will try your ideas today an see how it goes. Gary550 you know exactly what I am talking about great description of the problem. Iwll be checking and trying all of your ideas everyone and let you know the end results.

TX Chris
Mr. Fixit in the Family

[JoeLee]

As I mentioned in my previous post loose packings will cause your problem. When you pull the handle up instead of suching oil up into the piston chamber it's sucking air down in. Note: with the release valve open when you pull the handle up does it stay there or fall by it's own weight???

JL.....................