On my LT-155 the "lever" is a little black nob on a rod in the back under the fuel tank area. When you are behind the tractor, it pulls straight out about 2 inches.

If you are having a parking brake problem as I had on my LT-155. Get under the machine and clean out the grass and debris from the frame channel. On mine there is about a 3 inch deep pocket in the "c" shaped rail that makes up the frame. Using air, a screw driver, vacumn or what ever it takes to clean the pocket, solved my problem. It is now part of normal maintainence. All of the debris was not allowing the parking brake to work properly.

This debris in not apparent causal inspection.

The JD185 has a Sundstrand hydro. I'm not sure it has a release rod but it appears to have "tow linkage".

Perhaps this will help... click here

The Sundstrand hydro does have a bypass or tow linkage. Should be under the seat. Pull out to free wheel and push in to engage. See attached manual.

Here is a link that might be useful: John Deere 185 Tech Manual

185 hydro M72632 placement

M72632 spring