My breaks keep losing pressure randomly I've recently changed the front driver side break line and now sometimes when I drive it the peddle is squishie. Break fluid is topped up an no leaks any idea's? An also when breaking it pulls to the left quite badly it's a 1992 gen 2 Toyota surf.

 

did you bleed the brakes? or just swap the line?

 

Sounds like you still have air in the system, possibly in the right front if it's pulling left. Did you only bleed the left side since that is the hose you replaced? A "bad pull" is almost always caused by the front brakes, either a stuck caliper, bad hose or something different from one side to the other. But everyone defines "bad pull" differently, you could also check for something shifting under braking, like control arm bushings, loose tie rods/ball joints. Also check to insure your rear brakes are adjusted evenly.
Spongy brake pedal means air in the lines 90% of the time, but it's not usually intermittent. Your master cylinder may be going out, but you need to fix any other issues first and bleed it well to be able to verify that. Make sure you don't have a blister (or cracks) on any of the other hoses, the best time to fix a leaky brake hose is before it starts leaking, and if you are going to be bleeding your brakes anyway, replace them now if they show wear or damage.