Reduced braking power depress brake pedal fully

1. Check the fluid level in the reservoir after bleeding each wheel. Add DOT3 fluid, if necessary.
2. If the master cylinder was disassembled or if the reservoir becomes empty, bleed the air from the master cylinder as follows:
   1. Disconnect the brake lines from the master cylinder.
   2. Slowly depress the brake pedal and hold it.
   3. Block off the outlet plug with your finger, and release the brake pedal.
   4. Repeat 3 or 4 times.
   
   
3. Bleed the brake starting with the one furthest from the reservoir and then the next furthest, etc.
   
4. Depress the brake pedal several times, then loosen the bleeder plug with the pedal held down.
5. At the point when fluid stops coming out, tighten the bleeder plug to 11 Nm (8 ft. lbs.), then release the brake pedal.
6. Repeat until all the air in the fluid has been bled out.
7. Repeat the procedure to bleed the air out of brake line for each wheel.
8. Check the fluid level and add DOT3 fluid if necessary.

SOUNDS LIKE THE POWER UNIT OR MASTER CYLINDER FOR BRAKES HAS GONE BAD. NO MENTION OF PULLING OR GRINDING BUT YOU COULD NEED BRAKE FLUID. I'D CHECK THAT FIRST AND CHECK FOR LEAKS. HOPE THAT HELPS..

Did you adjust the brake light switch correctly? To adjust the brake light switch, first press the brake pedal down a few inches, then pull the switch plunger rod out of the switch toward the brake pedal arm, as far as you can without using excessive force. Next, return the brake pedal to the pedal stop position against the pedal stop and pull the brake pedal toward the rear to push the brake light switch actuating plunger rod into the switch housing limited by the travel of the brake pedal arm rear travel stop position. This procedure automatically adjusts the brake light switch correctly.
If the brake lights still don't turn off with the brake pedal released, check the brake pedal arm for sticking or binding that is preventing the brake pedal arm from returning fully to the pedal stop when the brake is released.

Hi,
sound as if you really do have a problem!
From your description I presume that you are confident in doing your own work?
The quickest way to check your system is to use brake hose clamps to isolate each section of the braking system. I would suggest that you rent or buy a set of the clamps.

Put the truck on axle stands and make sure it's safely secured. ]
If possible have an assistant to sit in the cab and depress the brake pedal on your instructions.
Place a brake hose clamp on both front brake hoses and the rear axle hose.
Depress the brake pedal firmly.
The pedal should have minimum movement, and be rock-solid and you should not be able to depress it further.
If the pedal does go down when you apply it, the likely reason is that the Brake Master Cyl is by-passing internally, ie, only one section is active.

You stated that the M/C had been replaced. so we shall presume that the brake pedal is rock hard.
Go to the rear brake hose clamp and release it. Instruct your assistant to depress the brake pedal. If the brake pedal moves a significant distance, then (a) your rear brake shoes require adjustment (b) rhere is a leaking brake cyl, (check for brake fluid in the drum) or (c) you have a "lazy' or a piston (s) which have siezed during a brake actuation. That problem will require removing the rear brake drums for further inspection. Not the problem? Then adjust the rear brakes if required, then depress the brake pedal again. The downward travel should now be noticeably reduced.

If all is well at the rear brakes. refit the brake hose clamp. Go to the passengers side front brake and have your assistant apply the footbrake. Pedal rockhard/minimun movement? Release the brake hose clamp whilst your assist has pressure on the pedal. spin the front wheel by hand, and note if (a) the brake pedal has excessive downward travel. (b) the brake pads are contacting the brake disc, (the wheel will cease rotating and you will hear the pads contact the disc.)

Pedal displays limited downward travel and pads contact disc? Refit the brake hose clamp and go to drivers side brake and follow the same procedure. If the pedal has excessive downward travel then you have found your inital problem.

If releasing both front brake hose clamps results in excessive brake pedal travel, then the problem will be easier to address if you deal with one side first, complete the resolution, test by using the brake hose clamps, then start / complete the other faulty brake.

Whichever side you start to work on, be methodical, boring as it sounds.
remove the road wheel, but before doing so, place a hand on the top and bottom of the tyre and rock the wheel away from you and check the bearing play. If memory serves me correctly, that year Dodge has the discs in one piece with the hub.

You have removed the wheel. Now, have your assistant turn the steering onto full right lock. Before continuing, I would like to remind you that the vehicle is up on axle stands and you have secured it safely, in order to conform with accepted safety parameters, correct?

The steering is now on full right lock and you can see both disc pads. Now, very carefully check the position of the caliper in relation to the disc pads. Is there and equal spacing on each side? Now, have your assistant release the brake pedal and very carefully observe the travel of the disc pad pistons. They should retract and the hub should turn freely by hand. A very light drag is allowed between disc pad and disc, but it should NOT be discernible when you rotate the hub by hand.

With no pressure on the brake pedal, and using an appropriate tool, attempt to have the caliper pistons retract into their cylinders / bores. Completed? Use caution as it is very easy to break / damage a disc by using undue force when retracting the pistons.

There is now an obvious gap between disc pads and disc (or rotor..sorry) Now, carefully check that the pad guide pins are not deformed and that the pads ride easily on them. if a pad jams when the brakes are applied, then, when the piston retracts, when force is removed from the brake pedal. There is an appreciable gap to close, upon the next application of the brakes!

Some types of disc pad retaining /guide pins are a tight fit, and it is very easy to tilt a pad when fitting the pins, causing the disc pad to fail to retract fully, and again, displayed by a brake pedal with excessive travel.

When the brake pedal is applied, the brake fluid has to fill the caliper piston bores, then exert pressure on the piston to force it against the disc pads, and they in turn are forced into contact with the disc. If the piston has to move an appreciable distance before contacting the disc pad, that takes more brake fluid to fill the bore of the piston, and the master cylinder piston has to travel further,resulting in a brake pedal that displays excessive travel .

I notice that you did not mention the type of effort or number of applications of the brake pedal which resulted in a firm pedal.

If you fitted replacement calipers, can I presume that you fitted new guide pins to the calipers?
Last but not least, (a) are they the correct calipers for the vehicle as regards piston bore size? The brake Master cyl will not be able to fill the bores of the calipers with enough fluid to drive the pistons out to apply the disc pads, if the bores are oversized. The pedal will also display excessive travel.
(b) If the brake master cyl is overfilled, when the brakes are applied, the master cyl will force fluid to the calipers, expand the caliper pistons, but will be unable to release the application to the pistons due to the fluid being unable to return to the master cyl as the allotted reservoir space has been filled with static fluid. When the brake pedal is depressed again, the Master cyl cannot service the caliper pistons on the first stroke as the pistons are locked at full stroke / travel in the bores, resulting in the brake pedal going to the floor, or giving that impression.
HOWEVER, that condition, if the vehicle is driven any distance, will result in the obvious odor of overheated disc brake pads, and the vehicle struggling to display any state of acceleration.
(c) Are they in fact the correct disc brake pads? It would be wise to remove a guide / retainer pin and check for free movement of the pad on the remaining pin. All ok, then refit the pin which you removed and test again. The pads have to be free to move on the pins, and thus align themselves with the face of the disc / rotor when the brakes are applied. Some people coat the pins with never-seeze or hi-temp grease when fitting them, others prefer them to be dry.

In closing, I would recommend that you check the full travel AND RETRACTION of the caliper pistons in their respective bores. It is not unknown for re-built / new parts to be defective.

It would be interesting to hear if any of the above proved to be beneficial in resolving your problem.

It should be bolted on. Depending on the model, things might look different, but a socket wrench set should be all that is required.
Maybe a pry bar.

Power Boosters Virtually all modern vehicles use a vacuum assisted power brake system to multiply the braking force and reduce pedal effort. Since vacuum is always available when the engine is operating, the system is simple and efficient. A vacuum diaphragm is located on the front of the master cylinder and assists the driver in applying the brakes, reducing both the effort and travel he must put into moving the brake pedal.
The vacuum diaphragm housing is normally connected to the intake manifold by a vacuum hose. A check valve is placed at the point where the hose enters the diaphragm housing, so that during periods of low manifold vacuum brakes assist will not be lost.
Depressing the brake pedal closes off the vacuum source and allows atmospheric pressure to enter on one side of the diaphragm. This causes the master cylinder pistons to move and apply the brakes. When the brake pedal is released, vacuum is applied to both sides of the diaphragm and springs return the diaphragm and master cylinder pistons to the released position.
If the vacuum supply fails, the brake pedal rod will contact the end of the master cylinder actuator rod and the system will apply the brakes without any power assistance. The driver will notice that much higher pedal effort is needed to stop the car and that the pedal feels harder than usual.

In all probability, the brake switch got stuck in the closed position. One way to test it is by trying to move the shift lever from Park to Neutral without depressing the brake. If you can do this, then the switch is damaged. It is very simple and inexpensive to replace.It is located a few inches above the brake pedal rubber pad.

Sounds like your brake light switch has gone bad. It is located on your brake pedal and is easy to change and relatively inexpensive. Let me know if you have any more questions. Thanks for rating my response and for using FixYa!

Raise the rear of the vehicle and make sure it is securely supported. Remove the rear wheel Remove the brake hose (A) from the suspension arm by removing the brake hose clip (B).Thoroughly clean the outside of the caliper to prevent dust and dirt from entering inside.Support the caliper with a piece of wire so that it does not hang from the brake se.
Remove the two guide rods (C) and caliper (D) from the bracket. Remove the pad shim (A) and brake pads (B).

Remove the pad retainers.
Clean the caliper thoroughly; remove any rust, and check for grooves and cracks. Check the brake disc for damage and cracks. Install the pad retainers. Check the foreign material at the pad shim (A) and the back of the pads (B). Contaminated brake discs or pads reduce stopping ability. Keep grease off the discs and pads.
Install the brake pads (B) and pad shim (A) on the caliper bracket. Install the inner pad with its wear indicator (C) facing down ward. If you are reusing the pads, always reinstall the brake pads in their original positions to prevent a momentary loss of braking efficiency. Rotate the caliper piston (A) clockwise into the cylinder, the align the cutout (B) in the piston with the tab (C) on the inner pad by turning the piston back. Lubricate the boot with rubber grease to avoid twisting the piston boot. If the piston boot is twisted, back it out so it is positioned properly.
Install the brake caliper (D). Install and torque the guide rods (E) to proper specification. Install the brake hose (F) onto the suspension arm with the brake hose clip (G). After installation, check for leaks at hose and line joints and connections, and retighten if necessary. Depress the brake pedal several times to make sure the brakes work, then test-drive. Engagement of the brake may require a greater pedal stroke immediately after the brake pads have been replaced as a set. Several applications of the brake pedal will restore the normal pedal stroke.

there is a ground problem, most likely in the tail unit itself, but a ground problem is hard to find and easy to fix. reground the system, the turning unit, and the problem should stop. About the hazards, I don't know...... some times in older cars, that is the way it works. because the brake and hazard element in the bulb is the same and the old cars used a break in the power, but the new cars use a break in the ground. any way, chase the ground down first, it is usually the cause.

check under dash for a leaky vaccum switch. if booster was faulty brake pedal would be very hard to depress.