Need hints on unscrewing Grohe nylon stem extension

I have a Grohe Roman Tub filler that has replacable cartridges which I need to replace. However the cartridges have a nylon extension on top of them that needs to come off first. It is a round cylinder that is screwed on the top of the cartridge and has holes in it that I assume you are supposed to be able to put a small round bar into to be able to unscrew it.

The problems is that the extension tube distorts when I try to unscrew it and I am leery of breaking it by putting too much pressure. I am looking for any helpful hints (that have worked) on how to get the extensions off so I can replace the cartidges. It is complicated by the fact that only the top 3/4 inch of the extension tube sticks above the tub deck, 2 1/2 inches of it are below the deck inside the valve casing.

My next step is probably to put some thread oil inside to see if that will free them. I really would like another option as I do not know how the oil will work with nylon threads on a brass cartridge top.

If I break the extension spindle then I really have a problem as it is goes down 3 inches into the valve.

Need the special tool

Most manufacturers make special tools to remove the various parts of the valve. I strongly recommend that you use the correct tool. I have most of the special tools and have cracked or stripped the nylon parts on occasion. Make sure that the part you are removing needs to be removed. Try tightening then uncsrewing the extention. As far as lubricants make sure that you use something that is NOT petroleum based. If you have the model number I may be able to give you more assistance.

grohes are high maintaince junk

good luck with that faucet.

you might be wise to get a plumber to tackle that faucet, or at least be sure you got shut off valves under the deck to isolate that particular faucet...

make sure you got a way to shut off that whirlpool unit, or you might have tu shut off the whole house for a while.


they are one brand I try to steer clear of because they can be an absolute nightmare to wokr with...

nothing like scarring up someones stubborn expensive faucet and be expected to give them a refund to appease them......

they arent worth all the time and trouble...

no special tools needed.
Just found the same issue, figured it out and wanted to resolve for others.
1. The inner tube (can be white or black) is just pushed onto the valve stem. Grab it with a needle-nose pliers and pull up and it will come off.
2. You can then put a small metal piece through the two holes on the outer plastic piece and turn counter clockwise to remove.

I think this is a Grohe extension kit Grohe 45.202.000 Extension For Low Profile Roman Tub.