I am having trouble with the brake system on my 73 dart 4 dr... anytime i need to get on the brakes more than a moderate amount the rear wheels lock up. any sugestions?

 

sounds like the proportioning valve is out of adjustment

 

This is a very dangerous situation. It's either the propotioning valve or the lines going to the front brakes are clogged (maybe partially). Possibe too is the front brakes are out of adjustment IF they are drum brakes. ( I'm betting that you have the disc brakes in the front though.) You must fix this. The possibility of "spinning out" is tremendous, especially at higher speeds.

 

A couple of other possibilities which might be worth checking out:

Has the car been stood up at all ? Those rear drums may be a tad rusty and will cause the rears to ****** on as they offer much more resistance than the front discs until the rust wears off the drum surface. This could take only a couple of blocks or a whole afternoon -depending on how bad the rust is. Be careful though -snatching brakes can rip the friction surface right off a brake shoe.

Secondly, one or both front brake hoses could be collapsed or possibly even a hardline has been crushed (by a badly positioned jack or stand for example). Brake hose can look and feel in excellent shape while in reality they could be totally shot.

Lastly the front brake calipers (or wheel cylinders)could be partially or completely seized as a result of having been stood up for a period of time. Check the fronts are working (and releasing) easily.

Any way you look at it, you need to urgently get this looked at -it's real dangerous for you and more especially other road users.

 

thanks for the info

 

this is a long shot, but make sure that the brakes in the front are bigger than the ones on the back