Try to keep it short. 98 24v did rear brake job. Replaced wheel cly. To flush I let both sides drip over night, resivoir didnt empty, dripped slowly . I think i screwed up doing this as i didnt have hose above bleed screw and let air into system. Have bleed three times, dont see air coming out, Pedal travels too far feels mushy, brake light and abs light are on. Bottom of master cyl resevoir is black with crud , cant clean up section in rear so havent bothered with the front either. SHOULD i TRY BLEEDING FURTHER BACK AND WHERE? DO I NEED ANOTHER MASTER CYLINDER? Trucks been down a couple of weeks , almost beginning to think i should have taken it to a shop but i have had some baddd luck doing that. ANY help appreciated thanks. Byron

 

I'll start with some of the tips , 1st using what ever you can to suck the old fluid out of the res. , even just a baster , then put just a small amount of new BF-brake fluid in , use to help in washing / rubbing out what ever is sticking to res.
Then suck that out , then fill to top with new BF , then open bleeders [ if they look rusty , spray a few times with Blast rust product , 1 & 2 days before ] , just let drain , but do not let res. go empty [ introduces air ] .
Then when breeders are dripping , close , check peddle , may need to about one pump / bleed for each bleeder .
Now on to your brakes , I would think that you are replacing because it was leaking , so air may be up to res. , also the valve that shuts off to leaking line , may have tripped , once this happens , you need to give a good hard peddle push to reset , when there is some resistance / pressure to the peddle , it should make a snapping / popping sound .
Letting the res. just drain & empty , is were you have created some issues , but using the directions above with two people & pumping should fix , but remember that at some point you may need to reset the valve , as soon as you feel some pressure , enough that you can not go to bottom , you have to push hard , so that the pressure from one side sets the valve back in the middle .

 

will give it a go thanks again

 

make sure that you have the rear shoes adjusted properly. that can give you that same issue.