73 ranchero 500, 351 C Hard pedal when cold and feels like brakes are dragging........when warms up it's fine? Booster or master cylinder maybe?
Power brakes can feel that way. A simple test for the booster is to pump the pedal a few times with the engine off, then, with your foot on the brake pedal, start the engine and see if the pedal lifts up to "normal" position. The vacuum in the booster can bleed off for a few reasons. Possible booster failure or the check valve on the booster can that connects the vacuum line may be leaking but without the engine running, you only get a few pumps of the pedal before you have only manual brakes requiring more pressure to make them stop. Check dragging by lifting a wheel off the ground and feel and listen for a shoe or pad dragging. Disc brakes will drag slightly and be normal, drums should be little or no dragging.
Thanks for the response Jeff. Hmmm....I've had MANY cars with power brakes and they've never felt like this before? I'll do the booster pump test today and see what happens.... When I say brakes feel like they're dragging I mean I can feel them stopping the car without me touching the brake, actually slow down the car.
Often overlooked are the brake hoses. They can come apart internally and create check valves inside them that will cause a brake to drag.
Sounds like a booster going bad. Try this: in an area that is safe (like a parking lot or industrial road after hours), drive the car and coast down to experience the drag then drive it again at the same speed and coast down then shut off the engine and see if the drag goes away. If it does it's the booster. I experienced that on my '74 Torino wagon ( after I rebuilt the front calipers when I had that problem) I also had what Hillbilly described on my neighbors Dodge van where the front brakes would lock up and would release when the bleeders were opened (both front flex lines were collapsed internally)
Ok, well....nice warm day today mid 70's and I just took her for a ride around town, seems to be working fine?? Brake fluid is full.....both times it's acted up it was pretty cold and car was sitting for weeks, maybe that had something to do with it OR maybe the booster IS going bad and it's sensitive to cold temps. Thanks for the input guys.
