Minecraft version 1.6.4
Tinkers Mechworks version : 0.1.6
Tinkers Construct version : 1.5.5.7
Forge Version : 9.11.1.965

The GUI element of the advanced drawbridge seems to not function at all. It resets as soon as I exit the GUI.
The extended drawbridge and the ordinary drawbridge functions as expected, but it resets after shutting down single player world. I could not find any mention of this problem being fixed in the changelog so I thought I should mention it here.

I believe I worked with drawbridges in my SlimeKnight test world, and didn't have this issue, even with those versions. Can you upload the FML log?

Sure. By the way, I now see i could have formulated the problem with the advanced drawbridge better. The inventory does not reset upon exiting the UI, just the arrows on the right side. I also included some pictures to better illustrate the problem.

The textfile was too big for pastebin so I went with media fire:

https://www.mediafire.com/?cs7xf4q75dvvdwd

I did some more testing.
In vanilla minecraft with only the same versions of Forge, Tinkerers Construct and Mechworks installed, the results are exactly the same as in my modded minecraft.
So I decided to test the 1.7.2 version of the mods on a vanilla 1.7.2 install. In that version the arrows on all of the drawbridges are working, at least until I exit and relog like before. Then they reset to the default position.
But the client crashes as soon as the THIRD stair is placed in the world by the advanced drawbridge. The same thing happens with an ordinary block like wood or stone. It does not chrash with less then three blocks.

Chrashlog:

http://pastebin.com/XRtAPBBw

Alright, I`ll post my findings on that issue there, keep up the good work and good luck with the GUI issue, would love to see it fixed.

That would be #37. Post those findings there and we'll stick with GUIs here.

I'm seeing a very similar issue, or maybe the exact same one.

My drawbridges remember orientation of stairs until the chunk gets unloaded. If the chunk has been unloaded since selecting the placement direction, the directional arrow selector button in the GUI stays the same (if the left-arrow was selected, it's still selected even if the chunk was unloaded), but my stairs get placed in the default direction as though no direction was selected.

Using a chunk loader will keep the placement-direction memory even while I'm away from my base, unless the server is restarted.

If the chunk has been unloaded, the direction must be reset by selecting some other direction, then reselecting the desired direction.

My version is: TMechworks-1.7.10-0.2.9

Just recently came back to this because I'm using Drawbridges in my Bevo'sTechPack SP world and have the same issue. The bug exists since 1.5.2 (SP FTB Unleashed), I think support for 1.5.2 was discontinued thus I didn't report because I thought this might be fixed in 1.6.4

The GUI needs improvement! For example it's impossible to make upside-down stairs/pistons.. Maybe add buttons for "Place Low/High".
Back in the day of Unleashed I tried to modify your code into this way, but don't have anything left from that time. I think I looked how vanilla did the directions with pistons and added some buttons, don't remember more...