Is there a way to adjust track recoil on a Heng Long version 5.3 King Tiger?

I know on the version 6.0 you can adjust the recoil level with the K + S keys on the transmitter, but that does not work on the version 5.3

No. 5.3 was not controllable by the main MFU.
There were aftermarket boards that removed track recoil for them.

Jarlath wrote:

No. 5.3 was not controllable by the main MFU.
There were aftermarket boards that removed track recoil for them.

Thanks Jarlath

As a quick & dirty alternative, I was wondering if it's possible to simply disconnect a wire.

I tried googling '5.3 wiring diagram' and found this, but I'm not sure if it's the correct one for v5.3. The main board seems to have a connector labelled 'track recoil'. 
https://www.rctankwarfare.co.uk/forums/download/file.php?id=63143&mode=view

Thanks again.

It is the two wires that connect to the small cotact switch that is on the BB/Recoil unit in the turret. When the switch closes (completes the circuit) the board then causes track recoil and the sound effect. No switch = No track recoil and No "Cannon Boom".

Shorting the switch means never ending track recoil and cannon sound effect

An option that has been done in the past without replacing the MFU is to use one of the following:

ATRC: Anti Track Recoil Circuit, when the recoil switch circuit is completed, this cuts power to the motors, thereby diabling the track recoil. Drawback, no shooting while moving (which is bad for the driveline with track recoil on anyways). I also do not think anyone makes a ATRC anymore...

MAKO: A plug in board that contains ATRC and makes the tank Tamiya compatible (to a certain extent). These have gotten very expensive... May be cheaper to buy a 6.0 replacement TX/MFU combo.

Jarlath wrote:

It is the two wires that connect to the small cotact switch that is on the BB/Recoil unit in the turret. When the switch closes (completes the circuit) the board then causes track recoil and the sound effect. No switch = No track recoil and No "Cannon Boom".

Wow, then I guess that's not an option - I like having the "boom" sound. Thanks for the info. Clears up a lot of grey areas for me.

I just got the KT not knowing it wasn't the latest version. Am planning to return the tank (it's brand new) for a 6.0 version so I haven't taken it apart. 

If that falls through, then I like your suggestion of upgrading the 5.3 to a 6.0. I see some places have the kits including the tx, looks like I'd have to get the IR attachments & wiring separate. Thanks again!