I have a 2000 Dodge Ram 1500 2wd extended-cab with 110,000 miles, 225-75-R16 tires and vacuum brake booster (no hydro-boost).
Normal stopping appears normal with no concerns. However, panic stops especially when loaded at all can be hair-raising, leaving me in the middle of an intersection in one case. The pedal is firm and does not sink under constant application. The vacuum booster tests shown in the factory manual appear normal. Pedal presure under normal braking situations feels normal with a nice light, sensitive pedal feel. Panic stops result in a very hard pedal requiring tremendous pedal pressure and resulting in sub-par braking action. I can smell hot linings after the panic stop even though it takes long stopping distance and time.
The ABS light and BRAKE light come on when the ignition is first turned on, so I know the bulbs are good. The lights do not come on otherwise.
I am kind of at a loss for an explantion, although I next plan to inspect the condition of the shoes and pads and look for any unusual indications too.
Any thoughts would be appreciated! Thanks. Nick
[u: 9900957f5f]11/20/2006 Update[/u: 9900957f5f]:
Thank you all for looking at my post, even though I received no responses.
This problem turned out to be very strange and misleading. Looking for all the world like a hydraulic problem to the rear wheels. With both rear wheels jacked up off the ground it was nearly impossible to stop the rears from turning stepping on the brake pedal with the engine just idling in Drive. The truck has limited-slip axle so both wheels turned together. Disconnecting the wires to the RWAL Control Valve to disable the ABS made no difference, so I was beginning to suspect the proportioning valve.
To try and narrow things down I got the idea of making several stops to heat up the brakes, then used my infra-red thermometer to check drum and rotor temps. Sure enough, the left-rear was cold compared to the right. Both fronts were within a few degrees of each other. I re-pulled the left rear drum and inspected the brake more carefully. I found that the front (leading shoe) brake cylinder pushrod had not been inserted into the slot in the shoe when the brakes were last serviced. This would cause that wheel to have no servo (self-actuation) action, greatly reducing the braking effect. The only pressure on the leading shoe was being transferred from the bottom of the trailing shoe. One reason I missed this on the first inspection was that shoe wear looked about normal. Only reason I can think of would be that the leading shoe might have been dragging somewhat due to the top end not moving in and out as normal.
The limited-slip axle really disguised this problem, making it much harder to find. I can't understand why the working right-rear brake could not stop the rear wheels when just idling in Drive. Once the problem was fixed, stopping them was easy under the same conditions. It also seems strange to me that this had as much affect on the panic stop as it had, although it's true that normal stops felt absolutly fine. It's very fortunate that no one was injured or killed due to the carelessness of the last mechanic who serviced the brakes. If anyone had stopped at the light in front of me I would have run right through them with my truck and trailer. I just could not stop!
To see a before and after photo of the problem, go to www. Car-drawings. Com/brake
Thanks for your interest! Nick
Friday, November 10th, 2006 AT 8:28 PM