Are these leaking blisters normal 4 week post tummy tuck? (Photos)

Thanks for your photos and question. Those blisters are not uncommon and are due to rubbing of the drains/binder on your skin. I tell patients to wipe them with alcohol and then rupture them. I would keep them covered with Vaseline and a bandaid. They should heal over the next few weeks without issues. Make to discuss these issues with your PS so that they can give you further advice. Best wishes!

It appears something rubbed hardly (maybe garment) or you used aggressive tape. If gets worst definitely must attend your surgeon office. Dr. Cárdenas 

Based on the photos, these appear to be related to tape or other dressings that may have been in place after surgery.  Tight dressings or tape can result is shearing of the skin as it normally swells after surgery.  Think of it as a very superficial sunburn that blisters.  I would cover with Vaseline or Aquaphor and a dry bandage 2-3 times a day trying to avoid adhesives on the skin directly around the area.  The ski should heal well on its own in 1-2 weeks.  Swelling after surgery is normal and may take longer to resolve.  It dies appear that you will have a very nice result.  I recommend seeing your surgeon to discuss your concerns.  Good luck.