Ok so a couple years ago on a rare occasion my 99 Jeep Grand would get a weird front end vibration and get really hot (both brakes and motor ie brakes sticking) typically on a longer drive. I never worried about it a whole lot but it started happening more frequently. After some research and talking to some people I was convinced to replaced the rubber brake hoses and calipers on my front brakes. I replaced the drivers side first as this was initially where I felt the most heat. It seemed to take complete care of the problem for several months and then it started happening again so I replaced the right side after they felt hotter than the drivers side. It again seemed to work fine for a couple of months (this car isn't really a daily driver as I have a company work van). Eventually the problem returned. Each time after replacing the rubber brake lines and calipers I bled the breaks at the front calipers.
Not long after replacing the second caliper/hose my heater core started leaking and I had to take the dash out to replace it. I had also been having an issue when sitting at a stop light I would get a loud squeal from the brake booster. So while the dash was out I replaced the brake booster. I did not unhook the lines to the master cylinder when I replaced the brake booster. When I got everything back together, after a few short drives that were trouble free, I got a really bad shimmy in the front end again and my front brakes were extremely hot. Hotter than they had ever been to this point. After looking around I thought that perhaps I hadn't adjusted the brake booster properly so I took it back apart but was unable to find any way to adjust it. My service manual makes no mention of any adjustment. I now have new front calipers, pads, rotors, rubber flex hoses and a new brake booster and my problem seems to be worse than ever. My rear brakes do not appear to be sticking. I have an infrared thermometer and after a 10 mile drive my front brakes give a reading over the infrared's limit of 600 degrees and the back brakes will be 120-150. I know the front will be hotter than the back but I've checked my wife's 2001 jeep grand after the same drive and heavy braking and her front brakes are barely over 200 degrees when I get out and check them.
After replacing the calipers and hoses I simply didn't notice any real difference. They were lightly sticking and they wouldn't stick constantly or predictably. After replacing the brake booster they seem to stick every trip out. I have noticed that after the car sits for a while (ie overnight) when I first drive it the brakes don't stick but after a 5-10 mile drive and a short rest at say a drive through window or a run into a store, when I get back in the car and start to drive the brakes will start to stick and within 5 miles will be so bad the entire car shakes.
I am almost convinced that the new brake booster is either not correct or in some way bad. Problem is, I can't find the receipt and the parts house I brought it from can't seem to find a record of me buying it so I'm going to have to pay for a new one. The guy at the parts store after listening to my story seemed to think I may have air in the lines. My pedal is stiff, I've never heard of air causing pedal stiffness it's always the other way around right?
Anyway I don't see any crimped lines (I had that happen on an S-10 a few years ago and this doesn't feel like that felt either), I bled the lines after opening the lines, everything but the master cylinder is new.
I just don't know what to do or check at this point.
1. Can you adjust a brake booster on a 99 grand cherokee.
2. would air in the line cause a stiff pedal and brakes sticking?
3. if not what else can cause this?
I'm not a novice although I'm not a mechanic, I've never taken any vehicle to a mechanic for any issue. But I'm about at my wits end with this one.