Need some help. When the engine is old and I hit the brakes like I normally do, it goes into a nose dive and comes screaming to a hault. Like there are no rear brakes and the front braking power has doubled. As the engine warms up, it gradually fades away,and completely disappears when at operating temp. Anything I could check before I hit my head on the windshield? I'm trying to save my pennies and would like to avoid paying someone to fix it. Thanks.