Staining on the metal case below the modules is a telltale sign of leakage

This is an abnormal amount of corrosion on the module.

Check for broken voltage sense wires. Some corrosion on the nuts and busbars is normal

Numbered modules means that someone has already been here before me

Remove all the terminal nuts and bus bar holders

Removing  module bolts from underneath

More evidence of leaking modules

Removing temp sensors and bottom tray

Streaks from leaking electrolyte

Better view of the staining

Corrosion from the outside of the terminal is not normal. Also, staining on the side of the module

Let's remove the vent tubes before disassembly

This is a good time to check the voltage of each module and make note of any that are significantly lower

Remove the 4, 12mm head bolts holding the battery together.  Battery must be cool or modules will swell and can be damaged

Turn each module over and check the bottom for leaks, including the hold down threaded socket

aha.. the two that were near the leak show leakage/corrsion on their bottoms

Putting it back together (would have been easier to disassemble from the other side)

the two labeled modules are tested replacements for the leaking modules

Make sure all the modules are lined up squarely before bolting them back together. Tighten the bolts one at a time gradually to apply equal pressure. You must bolt the pack together before charging

Deoxit100 reverses corrosion

I work the Deoxit100 in with a brass brush. Do not do this with the bus bars installed or you will cause a short circuit!

When removing the busbars from their holders, spread the side of the orange holder so the busbar will clear the small orange protrusion

One side of the battery has the "voltage sense" harness that connects to the ECU inside the battery case, and the cables that bring power to and take power from the battery.  

The voltage sense wires are connected to every other module, forming 14 blocks of two modules each. On this side you push the bus bar and silver tab for the voltage sense wire form the backside together while spreading the orange tab.  The voltage sense tabs should be sprayed with Deoxit100 and gently brushed, if you can, without removing them from their orange holders in order to avoid breaking their connections.