After gaining a general understanding of your door keep in mind the easiest way to prevent leaks is to keep your tracks free of debris and your plastic or metal rollers clean.
Sliding door leaking from top.
Check to see which door moves and which one is the stationary.
Aim a garden water hose with a sprayer set on mist or low at the outside of the sliding door.
If you have a problem with water leaking it will usually be on the bottom track threshold of the non stationary door.
Above the door is a window new last year installed.
I resealed all the bricks outside with mortar and new roof gutters are clean.
I used this tape for sealing.
How to fix a sliding door leak.
Flashing is a protective sealing membrane designed to protect a wall at its most vulnerable points namely where window and door openings exist.
Leak comes from the top of the door frame and going down on side frame to the bottom inside the frame and drip at the same time a bit from the top of sliding door on the glass.
Check the weatherstripping or flashing.
Test the door for the location of the leak.
Be sure to tape thin sheets of plywood over the glass to protect the door from flying pieces of concrete.
In this video i show you how i repaired a leak by replacing an incorrect capping job.
To slide the heavy doors along the metal frames the doors use metal or plastic rollers.
Leak happen when it is a heavy rain with wind blows same direction where is the door.
Once you ve exposed the top sides and bottom of the door you can assess what needs to be.