Brake Troubles

[Topsy]

I've got an old mountain bike, bought in 2009 I think (only yesterday did I realise that it's been so long!), which has not been in use around 5 years due to the alu frame feeling like it wants to disintegrate.

I'm kinda looking to have a mountain bike again, frame only, my head is kinda saying yes but my wallet is desperately trying to say no.
I'm trying to figure out what parts I can use off the old bike to sort of make a budget.

- Years ago my brakes stopped working, Shimano XT '08, my mate thought they had a bit of a reputation to start leaking so I thought it's them, tried to fix them a few times without much success.
- Three years ago I put the Magura Louise I had on my fourplay onto the front of the mtb and that worked well - for one day. Next day I pulled the lever and nothing happened, no air in the system and bite point and the pressure are there, but all I got was screeching. New pads and well cleaned disk. Also with the XTs the front was affected more than the rear, but I know that the rear is slightly shagged anyways as it started pulling air.

So I've been wondering if my fork is pissing over my front brake? It doesn't look like it, but something is messing up my brakes.
The fork is a Fox Talas 32 RLC. Found a servicing guide online but never done it before, don't necessarily want to do that right now as they seem to work.

I've got one more pair of brakes I can try, just to see if they'll also stop working, other than that I'm out of ideas.

Has anyone got any different suggestions?