Linhof suggests petroleum jelly (Vasoline) to lubricate the rails on the Technika series. I've used it and it works. Spread it on very very sparingly. Wipe off any excess. I've used it very lightly on the rails on my Speed Graphics and my one Busch Pressman. If using the camera in a dusty outdoor environment, wipe clean and reapply after use.
For the bellows, I use a vinyl/leather spray conditioner used on car seats. Spray on a cloth, wipe on sparingly, wipe off any excess, and let the bellows dry out a day or so before compressing again. Be careful and support the bellows with your hand underneath.