1999 Volkswagen Passat ABS light on

I have 99 Passat. There was a problem with ABS/brake light being on/off and beeping. I've found on the internet that electrical part of the ABS unit may be the cause. I follow instructions, disassembled the unit, solder two disconnected wires and put everything back. Now only ABS light is on and is solid. I suspect that during the process lubricant from ABS module leaked. When I was putting everything back I noticed that hydraulic part is completely dry. Will adding some lubricant help and what kind of lubricant should I use?