Due to some dodgy pads from superstar my bike was front brakeless. Unfortunately during the time it has been outside my back door my uncle has pulled on the lever several times making one of the brake pistons come out and all the fluid pushing it too has also come out.
Is this ok to fix? I ordered a bleed kit for shimano (my brakes are deore M535) as I can easily put the piston back in.
Please advise.

Its been a bad week for me bikewise. When washing my chain I accidentally threw away my powerlink. My brake pads came away from their backing plate, my rear hub has become loose and now the brakes have no brake fluid in them. SO annoying considering the weather. I have been busy on another project though (not bike related) and I might post some pics of it when its done.

carefully push it back in, bleed it and hope for the best…

else you can get bargain LX callipers on ebay every now and again (£15 or so)

Make sure the seal around the pisyon is OK, fit and bleed – should work as before. Oh and make sure no crap gets inside!

I managed to pop out a piston on my front LX brake, the piston didn't leave the caliper, it just sort of tilted a bit, but I lost all the fluid. With plenty of info. and support from the folk on here I popped it back in properly, bled it and it's worked fine since. A mechanic in a LBS insisted that it needed a rebuild with new seals but I've had no problems.

If the worst comes to the worst you can get a new LX caliper and centerlock rotor for £20 on CRC.

Same as with motorbikes- every manufacturer and most mechanics will tell you you need new seals, but chances are you'll be absolutely fine. Just make sure it's all clean and carefully refit. Oh, and there's no need for a bleed kit for those brakes, though it cna make it easier.