Dying bench seat

[AirSpeed]

When I bought my 72 k1500 it had a newly upholstered bench seat, has a really nice weave pattern and seems like good quality fabric but it's the wrong color. It's kinda beige and doesn't match the Orange and black interior. I've had a seat cover over it for five years buts it's worn out now so I'm thinking about dying the upholstery. It seems to be cotton and polyester, it's really thick fabric. Have any of you dyed your seats? If so did you have to take the fabric off the frame or do it in place? What type of dye did you use?