Source: Steam Community (opens in a new tab)

Have you ever been upset you almost killed that tank but the player has repaired it to 100%?
And you can't even heal yourself to 50%?
Balance has changed!
Now Repair will restore only 50% of vehicle's health, and the Medikit will heal 100 hp
(it wouldn't be 100% if you have the Armor)
Also Repair/Heal is not instant anymore! It takes some time to perform the action.