I got a question I thought I would ask to see if anyone else has had this problem at all. OK, I have a 2000 SLT Durango and the rear breaks do not lock up at all, only the front breaks work. The pedal is soft and goes all the way to the floor before the fronts lock up. NOT GOOD!!! There is no loss of fluid anywhere in the lines or in the system at all. Also the ABS and the Brake light are on all the time. Can the vehicle speed sensor be causing the rear breaks not to be working? I have heard that when the ABS and Break light are on that the vehicle speed sensor in the rear axle could be causing that. I have not taken apart the rears to see how they are yet. Planing on doing that the next few days. Let me know what you think

 

First of all, did this just come out of the blue, or did you recently have work done on the truck?

The first place I'd look is at the adjusters if you have drums in the rear. If they are too far in the brakes won't work and those two lights will come on. Adjust them out until the drums ever so slightly rub the shoes.

If that isn't it, it could be your master cylinder has an internal leak. The only way I know to test that is hold the brakes for an extended period of time and if the feeling in the pedal changes as time goes on, the master cyl is bad.

If thats not it, it could be a problem with the proportioning system or ABS system (hydraulic part of the ABS, not electrical).

 

Hi,

If the ABS light is still on, you could connect an ABS scan tool and see what the problem is with the ABS system.

A few other factors that could cause a soft pedal is the brake booster (lack of power assit), and like the other poster stated, a bad master cylinder. Plus the obvious, air in the lines. I would also check the flexible brake hoses also for kinks, bulges and so forth.

To test the brake booster, engine off, pump the brake pedal until the pedal is firm. Hold the pedal down and start the engine. The pedal should lower slightly then hold its position. You can also check the check valve on the booster along with all the vacuum lines.

Another way to test the master cylinder is to pump the pedal at least 20 times (you will need help for this), have the helper hold down the pedal on the last pedal pump, then take off the master cylinder cap. If you see air bubbles or a squirt of fluid, then that will indicate air is trapped in the system, thus the soft pedal. Thats fixed by bleeding all the brakes lines.

Hope this helps.

 

Negatory, but it may be a good idea to replace the sensor on the housing as you suggested. That will make the abs system inoperable if faulty. When checking the rear be sure to look over the adjusters for any faulty parts as 95 has mentioned.

Try replacing the sensor and then reset the pcm to see if the abs/brake lights go off. If the system is still spongy try to bleed it out completely making sure no air gets in @ the resivior, if to no avail bring it to a dealership.... If work was done previously and air was introduced to the abs box the dealership will have to cycle/purge the system.

It's the reason you stop safely, dont take any chances....

 

I had just purchased this last month and it has been like it since then. The rear breaks do not lock up at all and for that reason I am thinking that it is more of the Rear ABS pump(Module). Mine has RWAL (Rear Wheel ABS) only. SO I am thinking that this is bad since I noticed that the front one was replaced at 75k

 

UPDATE!!!! Problem solved!!! The entire problem was both the rear brake line were rotted and there was no fluid in the reservoir. Spend 2 hours replacing the left and right rear brake lines and bleeding all 4 brakes. Result: No more ABS Light, Brake Light and Soft Pedal. I now have a firm pedal, no lights on dash and all 4 brakes lock up and ABS work in the rear!! So this was nothing that any of us thought. Man I wish I would have looked at the brake lines sooner!!

Well thanks all for the suggestions to help resolve this.

 

Well we would of suggested that if you didnt mention the following on the first post
But great to hear your system is now back in order, congrats

 

Ive just started getting a very similar issue on my truck.. The ABS light is on as well as the brake light. The pedal feels like its lost its brake boost because it stops a bit too close to the floor. I still have vacuum going to the boost assy. and if I disconnect the vacuum line I do feel a difference in the pedal. Ive only been able to look at it for a few minutes but it doesn't seem to have any leaks in the brake lines. I'm not losing any fluid but I am getting air bubbles up in the reservoir. My first guess would be the master cylinder because it happened all the sudden when starting up the car the next morning. My second guess and my biggest question is that i noticed that the brake line on the rear axle had a burr in it from coming in contact with the exhaust pipe. The line looks to have just lost its plastic shielding because the internal metal braid is still in tact but would it be possible that the brake fluid boiled?? what is the boiling point of the brake fluid and would the pipe get hot enough to boil the fluid in the line??

This happened all the sudden the morning after hauling a half cord of wet wood in the back.

 

I had the same problem but mine was bad steel break lines. I had to replace both my break lines in the rear.

 

was it the solid lines or the steal braid lines??