Why do brakes pulse during braking - 1996 Dodge Ram

As a general rule, if the wheel shakes when you apply the brakes, the front disk rotors are warped. If the brake pedal pulses when you apply brakes, the rear brake rotors are warped. So you most likely have warped rear brake rotors. The noise may be that the wear indicators on the brake pads are touching the disks, indicating that you need new brake pads. Given both of these, I suggest a trip to the local brake repair centre is needed.

Is your ABS working properly? Under heavy braking the ABS should engage and 'pulse' the brakes on/off. It is normal to feel the brake petal flutter or pulse under your foot.

Under light braking there should be no pulsing as the ABS does not engage and you have changed the rotors and pads.

What you have sounds like warped rotors. They will cause a pulse or vibration in the brake pedal. This can be caused by:

1. Rotors worn too thin.
2. Riding the brakes and/or constant hard braking
3. Sticking calipers (usually also have a pull to left or right)
4. Worn or out of adjustment rear brakes causing excessive load on front brakes.

Then the job either wasn't done correctly or you have
ABS System problems

You need professional tools to work on ABS

A common cause for the vibration when braking is when front brake pads are replaced, but the brake rotors were not resurfaced smooth. Overtime when braking, the new pad will wear into the rotor that was not cut. The uncut rotor, having high and low spots when turning, will cause the brake pedal to vibrate/pulse when stopping.

Your Anti-Lock-Brake system has a problem. If it has failed completely, your brakes will lock up if you brake hard enough to cause a skid. The system is designed to send a pulse through the brake system in order to prevent skidding during hard braking. The system is very important to have working properly especially in icy or wet conditions. Go get it checked ASAP.

Warped brake discs or drums.

Two possible causes to the pulsing. Lets start with the least expensive first. Warped Rotors. Brake rotors/discs get extremely heated during braking and if you drive in the rain or drive through some standing water at the right time, the Heat and Cool cycle of the braking and then quenching by the water can cause the metal to warp. Even a slight warp will cause some vibration in the front end and a pulsing in the pedal. If the rotors havent been turned during the brake job or replaced I would look here first. The only way to determine is if the wheel is taken off and rotor visibly inspected. Second and most costly is the ABS Control module. Best way to explain is in a small box under your car in the middle by the drivers car door are 6 little plungers... to visualize think suction cups arranged like a 6 pack of coke. When you press your brake peddle in an ABS car these plunger open and close valves to in effect pump your brakes very very rapidly. ABS systems took the old 1970's pump the brakes and automated it. That helped prevent skids when people slammed on brakes during wet weather or accidents. They are controlled by a computer unit called a Control Module (Kelsey ABS Control for GM vehicles) when this starts to go bad you get the pulse in your pedal as the ABS system actuates improperly. Good news is even if the ABS controller goes out you WILL still have brakes, just not ABS brakes. Now lets get to cost. A rotor for your car depending on quality and type runs from 25 to 85 dollars (higher price is for more of a racing/speed type set up with frequent braking not everyday driving.. they are slotted and drilled to dissipate heat faster) Labor at a local mechanic to replace is going to be about $80. The ABS Controller module for your car runs from $745 up to $1100 dollars and the replacement cost is going to be about $200 for labor.

THis is usually a rotor or drum out of true. Replace or resurface as needed. Rotors need LOTS of thickness to avoid warping, during normal braking. Often it is similar cost to replace rotors and so not resurface old ones...

new rotors, machine rotors or just a pad slap?
pulsing indicates warpage, is if felt in the steering wheel or the brake pedal? did you do front and rears?
is it drum or all wheel disc brakes?