Hello. I have a 4 stop dual above ground 3 stage telescopic Tac 20. It is racking along with an occasional loud bang As it gets close to top floor. I can manually sync up the jacks and it will run smooth for maybe a day or so. The car syncs up everyday at midnight also. No fault codes and no air in lines. Oil is clear . There are no signs of oil leaking from seals. Is this possibly the inside seals and synchronized valves causing the problem ?

Yes, those jacks will have both internal check valves and internal seals at the bottom of the second and third stages of the pistons. Either one can fail and cause the jacks to go out of sync and rack. If you have either failing you should replace both when you have everything taken apart.

Clear sign the internals are leaking.....do yourself and the customer a favor and use the gorman packings do not use the ones that you get from tk

Couldn’t agree more, the ones from gorman fit properly. Also the manual to replace them is on the vertical express website, followed them step by step and had no issues

What information will I need for gorman to order Correctly ?

Check out their website under the telescopic section, you’ll probably want the 2.5T III 3 stage kit. I think they have different packages, you’ll want the full seal kit and if you do one jack, you might as well do the other

Thanks. The 2.5T. III 3 stage is the only 3 stage telescopic complete kit Gorman shows on their website for thyssen so I guess that must be it. I will call them Monday morning to confirm. It’s about 500$

That's the correct one. I always replace the check valve on the bottom also just because. Remove the 4 half inch bolts drop the check valve retainer plate/cap thingamobober. Just pull the check valve out. There will be an oring up inside of there you'll want to replace also. Jacks Green Slime is your friend. Be careful not to accidentally drop the check valve down the casing. Don't ask haha.

A good strap wrench (with light grit sand paper to put between plunger and strap for grip), a small chain wrench (for upper two heads)and a big chain wrench (for lower head) have been tools that make the job easier for me.

The check valve is not part of the kit? That needs to be ordered separately from vertical express?

Has to be ordered separately. I heard from vertical that the check valves made after 2004 (give or take a year??) don’t cause issues. I have always had good luck just changing all the seals and orings. It’s been a while since I’ve looked at one of the older, problematic check valve, but I don’t think they are tapered at the top and probably cause problems by cutting small o ring inside bottom of plunger?

Have you tried taking the springs off the buffers and doing a jack re-sync I’ve seen where the check valve doesn’t release unless you land the car all the way onto the buffer stands Fjr is the ims command

Yes I have. Check valves and Gorman seals are ordered.