Walker Pneumatic J612 Jack Issues

[pelletman]

I am in possession of a Walker J-612 pneumatic hydraulic air jack that my dad took apart 20 years ago. He told me the air cylinder wasn't cycling and that the hydraulics worked fine when he took it apart. He did not take apart the hydraulics. I cleaned everything and reassembled the jack. I am thinking there is an issue with the pneumatic cylinder still as it doesn't seem to puff out any air from the tube that goes into the hydraulic cylinder to jack the jack.

If I pull the saddle up it doesn't stay up. I would think that it would, the jack has oil in it, and the hydraulic unit has at some point been rebuilt by Walker as it has a sticker on it saying so. I think I need to make sure the hydraulic part works and then tackle the air cylinder problem with a kit. If anyone has any experience with one of these I would appreciate any input you may have.

Thanks!

 

[pelletman]

Hiball do you have any experience with these?

Thanks!

 

[pelletman]

Hiball do you have any experience with these?

Thanks!

 

[Hiball]

It sounds like you need to tear into the Hydraulic portion to make sure the Main Ram seal is good, outside of that the only other seals are the release, tank nut and where the air enters the side port of the unit. If the air side isn't cycling it could be a issue with the piston head seal or it has a early piston head that had plastic Vees built in and they are worn and you need to update to the newer style.

 

[pelletman]

Thanks Hiball!

My dad claimed the hydraulic portion was good. He said that you could poke into where the air goes in the side with a screwdriver and make the jack pump up. I have not been able to make that happen. I do have the air cylinder off and it doesn't seem to pump out much air, should I see a significant volume of air coming out of the end of the tube? I'd rather not tear apart the hydraulic unit if it works.

Do you mean update the piston head seal on the air unit?

Thanks!

 

[Hiball]

Thanks Hiball!

My dad claimed the hydraulic portion was good. He said that you could poke into where the air goes in the side with a screwdriver and make the jack pump up. I have not been able to make that happen. I do have the air cylinder off and it doesn't seem to pump out much air, should I see a significant volume of air coming out of the end of the tube? I'd rather not tear apart the hydraulic unit if it works.

Do you mean update the piston head seal on the air unit?

Thanks!

If it has a rebuilt by Walker sticker on it.... Might want to put eyes on it. I'm not sure what poking a screwdriver into the side has to do with the Jack operating. The amount of air that the air cylinder creates isn't a lot by any means, but there are wear parts inside that need to be sealing to create the vacuum/push required to operate the Jack. Yes... Depending on what Piston head your unit has, it's possible that it might need to be replaced, it's also possible that the Vees are in good shape. What I'm getting at is all of this speculation till you have put eyes on it.

I was thinking about the "sticking the screwdriver in the side" comment, I suppose that if the screwdriver shank was roughly the same size as the outlet on the air pump, you possible could create a good enough seal to move some oil if you pump it in and out. Could be rough on seals, but possible I suppose...

 

[pelletman]

I am aware of the seals in the side that compress against the tube that goes in. THey have been replaced. I bought the hydraulic rebuild kit by mistake. Which makes me think I may be able to get it to jack if I just use an air gun?

 

[Hiball]

I am aware of the seals in the side that compress against the tube that goes in. THey have been replaced. I bought the hydraulic rebuild kit by mistake. Which makes me think I may be able to get it to jack if I just use an air gun?

The Air gun would move any air that was already in the pipeline, but you would need the vacuum portion on the air upstroke to set up the next shot.

 

[pelletman]

Ah, OK. Thanks!

 

[pelletman]

Hiball I have been thinking about this jack lately, is there a way I could isolate what the problem was? Like somehow check the output of the air pump with a vacuum tester? I'd like to isolate the problem between the hydraulic unit and the air unit if possible....
Thanks!

 

[Hiball]

Hiball I have been thinking about this jack lately, is there a way I could isolate what the problem was? Like somehow check the output of the air pump with a vacuum tester? I'd like to isolate the problem between the hydraulic unit and the air unit if possible....
Thanks!

I would have no idea what amount of vaccum/output you would be looking for on a gauge.. My gut tells me that since the Jack has sat for 20+ years, more than likely the seals are kaput.

Order of attack..

1. Tear into the air pump, verify condition and whether the piston head uses a seal or is the older style with Vees built in.

2. Tear into the hydraulic unit and verify Main ram seal condition, cylinder bore etc.

3. If everything looks good, order up some parts/reinstall and know that you have a great piece of lift equipment.

Hope this helps

 

[pelletman]

Thanks Hiball! I have had both apart I think and I am much more confident in my work on the hydraulic pump than the air pum. I am not sure what you mean about vees, I will either see if I can find some pics and post them or open it up again. I'd really like to get this working, I love this jack cuz I am lazy!

 

[Hiball]

Thanks Hiball! I have had both apart I think and I am much more confident in my work on the hydraulic pump than the air pum. I am not sure what you mean about vees, I will either see if I can find some pics and post them or open it up again. I'd really like to get this working, I love this jack cuz I am lazy!

The piston head that slides back and forth in the cylinder had two different styles, the older style used plastic Vees that where molded into head and where not serviceable. The New style used a oring and was serviceable, the two heads are interchangeable on the rod but if you have the older one and its worn, well you guessed it, you will need the updated piston head.

 

[cubfarm 1]

That white air piston is very expensive.there is a "trip" spring on the 1/4 inch rod that is in between two large flat washers.that spring can break now and then. would not call it often. next there needs to be a rubber pad on the spirol spring on the back side of the air piston. This rubber pad shifts the shuttle in the center of the piston. there is a soft black rubber seal in the backside center of the piston. all of theparts to rebuild the air motor are in the kit.

 

[cubfarm 1]

Bleeding the air motor is fun. the 1 inch stem out of the large tube has a 1/8 pipe plug set screw in the end near the castor wheel. with the set screw removed i place my finger over the hole and run the air motor slowly. It should **** fluid out of the unit and then want to push it out past your finger. after a few strokes the air bubbles should be gone. then replace the plug. if the power unit is healthy it should lift the main arm as the air motor runs. the air motor rattles a lot when running with no real load. after the jack staarts to lift a load the motor will labor and "work" to lift the load. the air motor needs 175 psi as per walker/lincoln to lift the full rated load!!!

 

[pelletman]

OK guys, I downloaded the manual https://www.hcrcnow.com/uploads/drawings/walkerj612aj613aseriesa.pdf

Page 7 there are troubleshooting steps. I turned the jack on its side and ran the air slowly, no change. Opened the valve and pulled the saddle up and let go a bunch of times, no change. I looked through my records and I did order the entire kit for both the air motor and the hyd pump, so I am pretty sure I went through both. Here is a video, I am just looking for input on the video if you guys see anything suspect. Thanks!

https://photos.app.goo.gl/kkRLwbFoEsfRzTYX8