Rear brakes are SUPER touchy (98 dually)

[Turbo Trucker]

I just changed my front brakes (70k miles) and the rear brakes are really sensitive. They've always been sensitive but it's extreme now, at 15 mph just a light step on the pedal will lock them up for a couple feet (abs does work at higher speeds). I have to be real light on the pedal. Also, they will stick on a little at low speeds. Only thing I can think of is that a couple months ago I boiled the brake fluid on a down hill while towing, a bunch of smoke came out of the rear wheel wells and I had to add a bunch of brake fluid to get the brakes working properly again. I have inspected the brakes, I can't see anything abnormal. They are adjusted properly. Is it possible that the boiling brake fluid coming out of the pistons could have gummed them up or something?

 

[jwskrintney]

I have owned 4 Ram Cummins trucks and they have all had touchy back brakes under the conditions that you are describing... . I would not be too worried... . I think it may just be the nature of the beautiful beast. BTW I will not own the F**d PSD much longer..... I am going back to the superior Ram.

 

[mikel]

I had a '99 2500 that did not do anything like that. Any truck that will lock a wheel in other than a panic stop has something wrong with it. If it were me the first thing I'd do is pull the drums and replace the wheel cylinders. I can't imagine that they are in perfect health if they took the heat that was needed to make the brakes smoke.



Once you have the wheels and drums off you can inspect everything and see if the linings are contaminated or defective in some manner. IMHO it's just not worth it to take chances with the brakes or steering, too much of a safety issue.



Good luck,

Mike

 

[sam peterson]

wes---with the amount of heat that you are describing you probably cooked the rear shoes. any rear cylinder leakage should be corrected also. replace the rear shoes and while you are at it why not upgrade the rear cylinders to 1 3/16 to improve your rear braking. also replace the brake springs. high heat will take out the temper. inspect the drums for cracking. clean & lube the adjusters and all metal to metal contacts. when you get all done flush the fluid with dot 4 or better. ----Sam

 

[dan_gilson]

Normally boiling over will not cause leaks in the slave cylinders. The term boiling over comes from fluid boiling over the master cylinder.



If you have overheated badly you may have taken the temper out of the springs. You may have also glazed the shoes. Which may be the cause of the touchyness of the pedal.



If they are glazed make sure that you remove the glaze from BOTH the shoes and the drums. If you remove it from just one side the other will shortly become glazed again. Glazing reduces braking so you really do not want it.

 

[Turbo Trucker]

Thanks.



Weakened springs sound like what would cause the brakes to stick on. (I'm sure the Dodge dealer will want $50. 00 per spring, judging by the other stuff I've bought from them) I have looked at the pads, they did appear to be super smooth, I imagine I could use some sandpaper to remove any glaze from them? There's no leaks from the cylinders, so perhaps they are ok.

 

[dan_gilson]

I was specifically vague about how to de-glaze. I actually had to run to a meeting before.



On disk brakes I find deglazing pretty easy. I use a block of wood that is flat and 400 grit wet/dry sand paper. It works just fine for both the rotors and pads. Blow them off after sanding and shoot them with a little brake cleaner.



Drums and shoes are another thing. They are not flat and you could do some damage like flat spotting or gouging them. So, I can not recommend here. If it were me I would give it a try but I would be very careful and try to keep the sanding as even as possible. I would also be prepared to have the drums turned and shoes replaced if the sanding goes wrong.



Other thoughts would be to see of the stuff that they use to deglaze clutches could also be used on the rear brakes. Also to check with a good independant shop to see what they think or might do. Good luck!

 

[sam peterson]

wes---if you decide to try sanding the shoes and drums get some 100 grit paper and get at it. This is not rocket sicence unless you sand in one spot. Our brake shoe archer is fit with 50 grit paper and if you look at the surface of a new shoe you will see that they are pretty rough---goog luck---Sam

 

[dan_gilson]

The reason why I used 400 was at the time the brake pads that I was using were ~$150 a wheel. Those pads also tended to quickly wear into the rotors so I wanted to minimalize what I took off on both sides.



The rougher you make the pads the longer it will take them to bed back in.



Also, 100 grit would be pretty rough on a drum.