Cruise control makes brake squeal?

[avnav526]

Here's a weird one. My wife has a 2003 Baja Sport. A few months ago the right rear wheel started smelling very hot after she drove on the freeway. We took it to our mechanic and he changed the flexible brake line. He said the interior had deteriorated and was acting like a check valve, allowing pressure to the brake but preventing the pressure from releasing when we released the brake pedal. It seemed to be okay until a week later when we took a drive about 25 miles down the freeway.
While going down the freeway with the cruise control engaged that same wheel started squealing. When we got to the destination that brake was smelling very hot and was far hotter to the touch than the others. We took it back to the mechanic, and he couldn't duplicate the problem. My wife drove the car for awhile and noticed the problem only happened when the cruise control was engaged. Our mechanic and all my mechanic friends said no way they could be related; cruise control has nothing to do with the brake. So she quit using the cruise, insisting it was causing the problem. She told me the problem never came back.
We just drove our two cars 1000 miles from Wisconsin to Texas and she never engaged the cruise and had no problems. She still insists the cruise caused it, and I insisted there's no way, that it was mere coincidence. So a little while ago I drove her Baja and after just a few miles on the freeway with the cruise engaged the squealing started. We drove about 15 miles with the cruise engaged and disengaged. The squealing never stopped. Finally I exited the freeway and checked the wheel and rotor temps, and the right rear was burning hot. We let it cool for 15 minutes then she drove us back on the freeway without the cruise. The noise never came back, and when we parked the car that rotor was cool, the same as the driver side rear and cooler than both front rotors. Okay, I can't explain it but it looks like she was right.
I haven't a clue, the mechanic I called here at a Subaru specialty shop had no clue. We don't have time to leave it with a shop before we have to hit the road again, but I am hoping someone here can tell me what the heck is going on.
Scott

[alphasteel]

alright...I'm not a genius yet, and I would be on the same boat as you and the mec saying they aren't related. However if it really seems that they are tied together, I'm going to say either electrical(whether or not it be interference between the cruise control module and abs, idk) or vacuum related as the brakes and throttle(when under cruise control) are controlled via vacuum. That's my 2 sense, and yes I wouldn't think they are related either. But I also own a 97 ZJ which is renowned for having the most spectacular and fascinating assortment of electrical issues ever, and stuff that shouldn't have anything to do with something else usually does. If the car insists on showing they are related, maybe they are. I hate the idea of coincidence anyways. On a side note, handbrake is shoes inside the rear disk, check that too while your in there. Lot of things can happen with that if they aren't used that often or forgotten about in maintenance. Someone else will chime in as well with even more ideas and baja know how though

[avnav526]

alright...I'm not a genius yet, and I would be on the same boat as you and the mec saying they aren't related. However if it really seems that they are tied together, I'm going to say either electrical(whether or not it be interference between the cruise control module and abs, idk) or vacuum related as the brakes and throttle(when under cruise control) are controlled via vacuum. That's my 2 sense, and yes I wouldn't think they are related either. But I also own a 97 ZJ which is renowned for having the most spectacular and fascinating assortment of electrical issues ever, and stuff that shouldn't have anything to do with something else usually does. If the car insists on showing they are related, maybe they are. I hate the idea of coincidence anyways. On a side note, handbrake is shoes inside the rear disk, check that too while your in there. Lot of things can happen with that if they aren't used that often or forgotten about in maintenance. Someone else will chime in as well with even more ideas and baja know how though

Thanks for the reply. We pulled the disc/drum off and checked the parking brake. The parking brake shoes were not rubbing, but we did see signs that the inboard lip of the brake drum was rubbing on the backing plate/dust shield, which acounts for the noise and heat. Our mechanic checked the wheel bearings and said nothing was wrong there. With the car up on the lift there was no rubbing, and our mech is at a loss as to why it might be rubbing with the cruise engaged and no other time. He suggests we hammer the backing plate away from the drum. I guess we'll try that but it feels wrong, a band-aid fix that doesn't address the actual cause of the problem.
To add to the mystery my 05 Baja Turbo started squealing from exactly the same wheel yesterday while we were on the freeway but without the cruise engaged. I've owned the 05 since last November, I've put 10k miles on it and that's the first time it did that. We'll see if it does it again. I searched the web and haven't come across anyone else reporting this problem, and now it seems we may have two Bajas doing it. Weird!
Scott

[tomato_88]

The rear brakes are the use from the H6 outback. They rust up and cause dragging problems. I would give freak coincidence a good probability on this one. Where do you live? Does it snow?

[alphasteel]

tomato has a point with what they said...especially depending on your weather and road grime. I'm unsure about the backplate, i guess it depends how much it's rubbing and if it's only more noticeable when they get up in temperature? It's still not supposed to be rubbing in the first place though, so worth doing what you have to to fix it. What condition are the rotors/pads in now? if it gouged out the rotors the pads might have worn unevenly which can contribute to squealing. also if the sliders aren't in good shape or some lube/neverseize wasn't put on them when the brakes were changed, they may be sticking.