290enticer

I have a 99 f-250 with the 7.3 diesel. I also have a 90 powerquest 290 enticer i have just purchased. The e brakes are adjusted properly but will not hold on ramp. Thinking about installing " line locks" on the truck like that are on a race car, I can pump the brakes and lock the pressure on all four corners. Any suggestions or upgrades avaliable out there for these big trucks? Any input would be appriciated! Thankyou
Robert

Fixxxer22

look for a drive shaft mounted drum setup that comes on the ambulance packages or the f-53 motorhome chassis. lot less work and they hold very well.