Mushy Brakes

[Formula 40PC]

Hello everyone, this site has been oh so helpful with my recent CJ purchase, now for some more issues.
About a month ago I purchase a 1976 CJ7 with a replanted 360, autotranny and QuadraTrac . The breaks are mushy and feel as if they have a slow leak. I can push on the petal and they slow me down but then I need to let off and repress the petal again to get another burst of pressure. Where should I start with this problem? As far as I now the brake system is all original and still has drum brakes all around. I checked the fluid reservoir and there is plenty of fluid with none leaking out.

 

[Captainlance]

Soft brakes are always caused by a leak, check all lines, etc visually first, wet means leak! Pull the wheels, check for leaks around the wheel cylinders. Master cylinders leak too, many times you cannot see it, remove the 2 nuts holding it on and look at the back, leaks are common around the push-rod, fluid may even have leaked into the booster, if you have power brakes.

 

[Lumpy Grits]

Soft brakes can also come from air in the lines and failing seals in the MC.
LG

 

[Posi]

If they pump up, and your M/C is filled chance are you have air in the system.

 

[BajaEdition]

a 76 jeep is over 40 years old, there are a lot of places to look for the issue
1 replace all the brake fluid, most guys never do this, the stuff does draw water to it and gets air in it. go to sears and get a fluid pump that works on the calpers and draw new fluid through the system
2 if that does not work replace all the rubber hoses in the system, maybe do this first after all those old ones are very old
start rebuilding the slave cylinders and master cylinder

remember you bought an antique, and the last guy was probably tired of maintaining the antique. these things can have a lot wrong with them that is just age and neglect.