I've got a 136 head mounted on 161 legs and a 128LP head on 055 legs.

I wish to put the 136 head on the 055 legs, since to 128 is a bit broken and i need something light to travel.

Any tips on how to do this, or if is it even possible?

for the heads see: http://www.leoscamera.com/Acces/tripods/accesPod/aMFVidHead.html
for the legs:
http://www.castlecameras.co.uk/acatalog/Online_Catalogue__Tripod_legs_251.html

Turn the tripod over so the head in down. There should be 3 small slotted screw heads looking back at you on the flange. Loosen them up-don't take them all the way out, they're a PITA to replace, turn the tripod over so the head is up-hold the center column or top of the legs and give the pan handle a good turn counterclockwise. If that doesn't loosen the head then tap LIGHTLT with a soft mallet (your hand is better) until it does loosen. Once loose it you can keep turning it until it's off the screw on the colunm or ball.
Replace on the new legs in inverse order just remember to tighten the screws under the head or you'll be in for a big surprise when you go to pan the head.

HTHs
Don

How do you prevent the head from "panning" while unscrewing?
Do i tap the top or the side of the head?

Lock the PAN in place. Give it a good yank on the pan handle and you should be good to go

Don

Thanks Don,

Unfortunately, the 128head is busted, and i can't get the pan locked.
When i remove the panningknob, i'm left with a screw with a large screwdriverslit,
maybe i can use that to loosen things up.

Take a LARGE set of channel lock pliers (they kind plumbers use) grab the head at the bottom by the flange and give it a whirl. Other than that I don't know what else to try.

Don

Sigh, i think i've tried everything now. The 136head removes so easily with your instructions, but the 128 seems to be glued. I give up, and i'll have to do with something lighter for static shots only.

Thanks anyway, G's Frank.