Dana 27 Disk Brakes

I changed over to disk brakes a year or so ago on the front end. and have not had any problems till recently. The disks dont want to release. it all started when I repalced the master cylinder. The one I replaced was a duel reservior bendix with the 2 large hex shaped adapters that could be unscrewed to remove the residuel check valve. The one I replaced it with just has standard 3/8" ports. The brakes act like there is to much residuel presure on them to release properly. Is there some sort of check under the brass inverted flare in the line port?

 

Who manufactured the MC you are using? Was it designed for disc/drum operation or drum/drum use? Do you have the proper inline residual valves installed?

 

The origainal was a bendix drum/drum I took the part # off of it and cross referenced it to the replacement model. The only diference between the two is the new one does not have the large hex nut that you can remove to get to the residual check valve and remove it. I have a 3psi wildwood check installed for the front disks. The only thing I can think of is there is some type of check under the brass flare that I need to be removed.

 

I removed one by using a sheet metal screw. I threaded it into what appeared to be a flare fitting and pulled it out. It's likely that yours is the same way. As I recall, I pulled out the flare and there was a spring loaded valve or ball behind it. I pulled that and replaced the flare fitting. If you cross referenced it to your original and that one was for drum brakes, I'll bet your new one has a 10 lb residual valve in it. That'll definitely make your brakes drag.