[needtocamp]

As a result of Kim’s and Peter’s episodes with what appears to be related to either the caliper slides or failing caliper adjusters I am adding to my list of stuff I will check every time I am under the coach.

We have long advocated the practice of draining the tanks in sequence to check for moisture and the operation of the check and protection valves. Now I am adding a check on the brake calipers/

I am suggesting that anytime a coach underside is accessible these things should be checked at a minimum. To at least get some idea of if a caliper is dragging a brake the parking brake has to be released. With the brake released there are a couple of benefits. If the parking brake air system has a leak you are going to know it. It is part of the pre-trip brake check, but by the time a coach is put up in the air and other things are done, some time will have elapsed, so if the parking brakes are still released you know for sure the parking brakes will meet the DOT leak standard.

The second benefit is it will “loosen” all the calipers. With no brakes applied or dragging I expect each caliper can be grabbed and shaken a little. Any movement is an indicator the caliper slides are loose and the caliper is not applying pressure against the pads. This is not likely required on drum brakes, but on those you can release the parking brake and have a helper press on the service brake. That is an opportunity to verify the travel on the brake chamber rod is within limits, and it allows you to see the brake shoes relax and move away from the drum slightly.

[Archived]

Kim I am at home give me call only 2 1/2 hours from Denver I can help you 1-307-331-58. I am replacing the other four brake calipers just to be sure , but I am sure Jon will say you can service them but I don’t need the hassle just put new ones on and pads and be done with it, I think that the motor home coaches are in very bad need of checking the slide pins and the space between the caliper and rotor , in order to do it the right way , you need to take off the wheels and take pads out and slide the caliper to make sure it moves freely and check when the caliper is on rotor and park brake off and measure clearance between the rotor and pads

[Archived]

The calipers are serviceable, but so are service brake chambers. I have no intention of doing that given the need to have perfect operating brakes and the consequences of brakes with a problem. Both Kim and Peter dodged a fire. Been there, done that, never want to go through that again.

[Fred F.]

I certainly would agree these should be checked. In my case the chambers were all just replaced. I also while on the road, and even at home have little to no way get regularly get under the bus. In the past do that the two times per year the bus is in the air at a facility.

Thanks for the advice everyone, this could have been a real problem without the tire monitoring system. Having a system where the sensor is as close to the hub and rotor as possible was certainly a plus. Seeing the temp start to rise without corresponding drop in pressure immediately gave me high level of concern. Even slowing down immediately and looking for safe place to pull over (around three miles) allowed things to get hot enough for smoke. I would imagine that without the monitoring system a fire would have been a real possibility. I am not sure how anyone would realize they had a problem without the monitors since there was NO change inthe perforance or other measures while driving prior to seeing the temps rise. I alarm did not go off since never reached the level the alarm is set for until I was just about ready to pull off of the road. If I had not stopped there the next safe spot (I pulld off there also to shoot the temp of the rotor/hub with the IR after brake caged) was over 40 miles away. Thsi was not on an interstate but rather US 40 through the rocky mountains of Colorado (think twisty turny and up and down one lane each way with little to no shoulder, and certainly no place to safely put the bus). Had Deb get onto Google Earth to find the pullout spot we used. Luckily had decent cell service there, and she always has an Ipad next o her seat for emergency look ups. She saw the pull out less than 1 mile before we were there on Google Earth. Worked well. We were totally off of the road. I immediately disconnected the Jeep in case fire did break out. Had Deb stay out of the coach until we knew no fire. If fire had started not a good location, if there is ever a good location. Also had 2 fire extingishers out of the bus and atthe ready if diaster happened (none did). As Jon has mentioned it is not enough to have all of these monitoring devices (I also use a Silverleaf system built one of the LCD screens), you also, like a pilot, have to continuously scan these items t owatch for changes that are not expected prior to getting to the alarm points.

Sorry for the long post

[glen]

This is the 3rd brake problem in less than a month with caliper pins sticking and not releasing the brake.

Kim did a great job, did everything right and his TPMS saved the day. Smart Tire was a good system being clamped to the rim inside the tire, but they’re not available anymore.

Would Pressure Pro pick up the high temp, yes it would, but wouldn’t be near as accurate as Smart Tire since it’s closer to the heat source. Being as diligent as Kim and using the Pressure Pro Pulse, the problem wheel would have got noticed as the temp climbed for that wheel.

Even yours truly is going to upgrade to the Pressure Pro Pulse, these 3 brake problems make the cost of the system chump change compared to a potential fire, being towed or a breakdown that got worse because of a unknown tire failure or hung brake.

Contact me boys and girls for your Pressure Pro system.

[Tom]

I agree wth everything Tom said. From what I know the new Pressure Pro system is as good as it gets today. The Smartire sytem is not avialble. When my sensors stop functioning, and they will has the batteries stop, I will get the new Pressure Pro system. We must have temperature as well as pressure monitoring. As I said, the pressure in the tire staying normal with the temps rising is what alerted me to the probable brake or hub problem.

[Davy]

Tom, What is the difference in the PressurePro Pulse and the 16 tire Pressure Pro? Is it just the display?

Donald

[Mike]

Peter,’

Tried to call you, but the phoen number you gave was not complete.

[Peter]

Crap sorry buddy. 1-307-331-5801

[Archived]

Have used pressure Pro for several years and now have Pulse … from Tom. The first day I installed it, a few years ago on another coach, it picked up an inside dual pressure drop and ouside dual temperature rise and probably saved some sort of mess. Paid for itself the first day I think.

[Raymond]

Donald,

The Pulse displays both pressure and temps.

[AL]

Thanks Tom

[Raymond]

I looked very carefully at the calipers from Peter’s coach, The slide pins were all free and I have doubts they contributed to the dragging brakes I know Kim is pretty savvy about his coach and if and when he gets his issue resolved I am hoping he will look closely at his calipers and see if he agrees his slide pins were not binding.

If those familiar with the Knorr-Bremse brakes would chime in I think a further discussion of the potential causes for the two brake dragging events would benefit us all because these two incidents could have resulted in a complete destruction of a coach due to fire.

Jeff said after caging the caliper on Peter’s coach there was no dragging or heat when the coach was driven back to the shop. To my thinking that rules out a caliper with a failed internal adjuster. After looking at the slide pins I would have a hard time saying the slide pins were binding. So the only other thing I can associate with the problem was a brake chamber that did not fully release the spring brake. Interestingly both coaches had relatively new brake chambers. Coincidence or an indicator of a possible problem?

I would like to see if anyone has ideas.

[Per]

The old style slide pins had a groove machined near each end around the circumference, into which an o-ring was used, with the idea to keep road grime from intruding between the pin and the caliper bushing. Apparently those o-rings made such a tight fit that it contributed to hanging up the caliper. The new style ones do not have a groove and do not use any o-rings. I changed all my pins couple years ago. For the old style ones, I installed them without the o-rings, and some were the new style.

Would be nice to know if these events involved slide pins with the o-rings.

[Archived]

There were no O rings on the pins on the calipers from Peter’s coach.