TK Twin Post Holeless Telescopic Piston

hello all,
I have a 2 stop hydro (TAC-20) that has a horrible noise inside the pistons. Almost seems as if the smaller piston is bottoming out inside the larger piston when it comes to land on the first floor. Then when it takes off to go up the pistons seem to bang violently together. My question is, I'm sure there has to be some type of check valve to regulate oil flow between pistons, but where in the world is the check valve located? Is it in the cylinder? Between the pistons? This is the type of piston:
Model: 6501CH3
Also if anyone has a mechanical schematic that would be helpful.

thanks in advance for any and all help!

Not sure of this model, but yes the flow of all is regulated inside the ram, and they should rise in unison when oil is applied. It sound like there is a leak inside, particularly on the down motion if the higher sections are bottoming out before the rest are. Also sounds like some guides aren't working either. It sounds like you have to open the rams up. Not an easy task.

Perhaps these guys may be of some assistance.

www.itihydraulik.com

The check valve is located on the bottom of the second piston and if its a 3 stage jack there is one on the bottom of the third piston as well. These jacks also have internal seals on the bottom of every jack as well and if one of these seals goes bad you can also have sync issues as well. Unfortunately getting to these requires removing each piston individually.

Sounds like fun! I appreciate the feed back. Looks like we're ripping out some pistons next week!! I'll let you know how it goes!

The check valves are inside. If you take out the spring buffers and manual lower the car onto the stanchions, it should sync them. If it gets out of sync in short order, you probably need to replace the inner packing.

I have already tried to re-sync them both by lowering down manually also with IMS.

look what I found!!!

You found it! Its a fun oily journey to get there isn't it?

haha yes we had a blast!