I have a 96 F350 7.3L turbo diesel. The brakes work sometimes but become very hard. The brake light comes on and stays on but goes off within about 5 to 10 minutes. Is this a vaccum pump problem or is it a booster problem. All fluid levels are fine.

You mention vacuum is working, but the symptoms point straight at the power assist for the brakes being faulty, probably the vacuum accumulator. I'd stop driving it and get it looked at ASAP

There may be a switch on the equalizer valve. This is the valve that equalizes pressure to the 4 wheels.
The valve may be sticking or the switch may be faulty.
If the ABS is the problem, there should be a code stored in the body computer.

It appears that you have lost the vacuum assistance that works the power booster for the brakes. It is most likely that the vacuum hose that connects from the vacuum pump (which is usually located on the rear of the alternator) to the power booster has gone hard and split where the hose attaches to the metal piping. Check the hose for leaks or splits and re-terminate or replace as necessary. If the hose is OK then the problem could be that the vacuum pump is faulty or the rubber diapraghm inside the power booster has become faulty and developed a leak. A brake specialist would be the best option to sort out these latter problems.

Make sure the pedal is all the way up.
Check the brake fluid reservoir to see that it is filled to the proper level.

if you talking brakes not clutch. you can pump the brakes all day long and they don't build pressure and you not losing fluids the master is out. now if you pump them up and they are rock hard your hydrabooster is out.now if your mechanically incline you can order a master cylinder rebuild kit for like 20-30 bucks which is basically orings from local parts store and only tools you need are snapring pliers. or you can change the master ,bench bleed it first then bleed out the rr,lr,rf,lf in that order.hope i help.all under 100 bucks

could be vacuum pump. check for vacuum at line into booster (should be significant). if not ok, check for vacuum at pump to make sure it is not a line problem. if there is a check valve in the line, ensure it is working.

You may have a brake caliper sticking causing the sensor to trigger. This would also partially explain the hard shifting if the E-brake is dragging.

This is a common GM specific problem. Your turn signal switch contains an elaborate networking device that has to cancel brakelights while running a turn light. Often times the ground within the turn signal switch is lost causing your situation. After investigating such other possibilities as fuses and loose grounds it may become necessary to replace the turn signal switch. Thank you, Dana

I would think if it is a amber brake light its a sensor that read the rotor on your cv axle near behind the brake housing..

the easiest way to check if u have a bad earth is to get jumper leads and place the negative side of battery the other end on metal part of the body with no paint on it bull bar and check it again see how u go

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