Brake Problem Diagnosis P38?
#1
Brake Problem Diagnosis P38?
Have 1996 P38 4.6, 113,000 miles. Recently experiencing softer brake pedal and all (3) brake lights go on when I brake moderately hard. Some fade. Checked master cylinder and no leaks. Did OBD II scan and no codes came up.
New pads (12000 mi.), no vibration when braking. W/o vibration can it be a rotor problem or should I be looking somewhere else?
Appreciate advice.
New pads (12000 mi.), no vibration when braking. W/o vibration can it be a rotor problem or should I be looking somewhere else?
Appreciate advice.
#4
Your accumulator might be on the way out, or your pressure switch is failing. Accumulators usually go out ever 80k miles. They aren't very cheap $260 usually, but aren't that hard to replace. What does your Brake pump do when you push the pedal "moderately" hard? Just so you know, the brake pump supplies the braking power to the entire system. There is no traditional master cylinder. Basically the "ABS" pump which is a misleading name (I call it the brake pump) is a hydraulic pump that stores pressure in the accumulator. When you brake, a little pressure is released from the accumulator. After about 5 or so brake applications the pressure will drop and engage the pressure switch which starts the pump. The pump cycles until a certain pressure is reached in the accumulator and then it shuts off. If your pump turns on and off every time you brake, your accumulator is most likely shot. The pump is located to the right of the engine bay next to your EAS system. If you follow the line coming out the bottom of your brake reservoir, you'll find it.
#5
Thanks. When I brake moderately hard all three indicator lights on the left of the dash light up. There's a lack of pressure but not completely, not like when a master cylinder is shot. The pedal doesn't go to the floor but the braking isn't as sure and there appears to be brake fade. Before this problem the pedal was high and hard and braking so good it could throw you through the windshield!
#6
#8
Check the plug that goes into the ABS pump pressure switch to make sure it is properly seated. That is what turns on the dash lights. My guess is that the plug is loose and maybe you are just imagining the brake fade because you are seeing the dash lights come on. Just a hunch. I have found that most of the problems on these Rovers are just simple fixes like that. If that doesn't work, check for leaks in the brake system. If the accumulator is over five years old, replace it. Then do a brake bleed per the manual if you haven't already done that. Hope that helps you out.
#9
Join Date: May 2010
Location: Grand Forks, North Dakota
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Have you pulled a trailer or had some other occasion for the brakes to overheat? Dot 3 fluid will absorb water from the air (although minimal amounts in a closed system) which can boil out at much lower temperatures than the fluid itself. If the fluid is over five years old, and you've cooked the brakes, you may have created enough gas to cause the spongy feel.
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