Jeep Liberty/Liberty Diesel Brakes
Keep an eye out and see which SUV's or Trucks (imports) start installing rear drum brakes instead of rear rotor and caliper brakes. It is widely known that drum brakes are more "mpg" friendly, but lack the stopping power of rear rotor/caliper style brakes. I am wondering if efforts of making a better braking system has accidently invited additional heat. Weight, momentum and size determines the style of braking system, this according to most mechanical engineers.
Drum brakes are less costly. They worked OK during the 1950's and 60's when cars were iron tanks with huge engines. So what's so different now, only body shape and lighter materials. Lets go back to rear drum brakes. Any retro-fitted drum brakes out there that I could swap out with my rear brakes. Maybe others might be interested also.
John
Drum brakes are less costly. They worked OK during the 1950's and 60's when cars were iron tanks with huge engines. So what's so different now, only body shape and lighter materials. Lets go back to rear drum brakes. Any retro-fitted drum brakes out there that I could swap out with my rear brakes. Maybe others might be interested also.
John
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This is my first post and I hope it's not a silly question.
My wife has a 2002 Jeep Liberty, I purchaced a repair manual for it when I bought it and I'll be darned if I can locate it in my house.
I need to change a bulb for the break light on rear driver side, I opened the rear door
and removed the 2 inside screws. Everything seems loose but I can't remove the housing is there something somewhere else I missed to loosen? I don't want to just pull on it for fear of snapping something. Any help would be greatly apprecheated. Thanks.
What a weird coincendence. I just changed mine myself, and ran into the exact same situation. I had the same worry about snapping of some plastic part off and ruining the tail light for good.
Here's the solution from my experience;
The outside (for the driver side brake light, it would be the left hand side of the taillight as you are looking at it) of the taillight is held onto the body by (2) prongs roughly .25 diameter that snap into (2) holes mounted into the body. The prongs are located (1) at the top and (1) at the bottom of the taillight. The best way to remove it is to first remove the two inside screws as you did before. Second, you need something to pry the taillight off. I used a large flat screwdriver, sticking it in at the middle of the taillight between the body and the light. It's important that you work it slowly and gently. I do recommend using a cloth or something to cover over the blade of the screwdriver in order to prevent scratching the body or cracking the light. Thank God, I got lucky and didn't do either.
Good luck. Let me know how it goes.
Steve, Host
Now, the rotor is exposed to the elements, road salts and rocks. I am trying to find if this situation exists. Ok, take an ironing board, put some water on it and then slide a hot iron over the wet spot. Steam is created and the iron slides across the ironing board. So, when water is heated to a steam state, it becomes a lubricant (of sorts) and reduces surface friction. Does this happen with rotor/caliper brakes in wet weather?
John
Maybe someone over in Stop here! Let's talk about brakes can expound, but I don't why there'd be any difference.
Steve, Host
Can you change the "temper" of the (rotor surface) outside laminate (which makes contact with the brake pads)? I found an old rotor and discovered the interior is not solid. Rotors warp from heat or the tempering of the steel in isolated areas.
Even front rotors have problems with heat, warping and causing ball joints to fail. I have noticed this for some 20 years. I had a 1981 Dodge truck that was famous for bad rotors, bearings and ball joints.
I have to believe its the vendor or there is an monopoly of bad technology in which the car manufacturers are forced to purchase from.
I can't believe that everyone suffers from just caliper calibration problems. Look at all the recalls, even dating back to the 1980's about brakes. I have to conclude that all rotor brake products were defective, but its "theoretical" functionality and performance "trump'd" its failure quotient.
Rotors are a "consumable item", which means they are suppose to be replaced. I would like to check the specifications standards for rotors, say made in 1985 and rotors made now. Are the "spec's" the same between the two or have changes been made since then.
Can a caliper brake pads "weld" themselves to the rotor? This may be an extreme situation, but even if welding does not occur, look at the extreme temperatures which change the chemical temper of the steel surfaces.
I have to thank you guys at edmunds.com/forum. Everyone can't be crazy if we suspect our brakes are bad. Then the only conclusion I have to draw, its a design flaw.
John
In the case of fabric, liquid water (and steam) will remain trapped in the fabric providing a more or less steady supply of steam under the iron. The metal in your brakes is nonpermeable so any liquid water or steam is very quickly expelled.
tidester, host
-"Lucky Liberty"
Rotors in contact with metal brake pads goes along this same principle. This may be a monentary event, until the metal contacts exceed the temperature limits of water and it all evaporates away as steam.
So, it steam is generated, we are talking the temperature of boiling point, or 100 degrees C. Now, what are the upper temperature limits in which a rotor can withstand? I am sure many people, if under severe braking have not bothered to check their rotors if such an event happened. They just keep driving.
So, can rotors reach 1000 degree's. Smoking brakes reflect a breakdown of the hydraulic system and fluid gets on the hot metal. At 1000 degrees, hydraulic fluid is quite flammable. That's why hydraulic lines are metal instead of rubber (or should be metal). Not only worn brakes, but worn gaskets or seals in brake lines could rupture from the radiated heat.
Anyone who has welded their brake pads to the rotor, I would be interested what temperature reading that would be. Maybe exceeding 2000 degrees?
All these things are possible.
John
I think it would be a good idea, like you said, the technician showed you the brakes. Like a doctor visit, have some visual idea what is happening under the car when you slam on the brakes.
I don't know of any service shop who would invite customers into the work area, like on a guided tour to examine what is wrong with their car. Unfortunately, what most customers sees is their bill, with the prospect that the problem will reoccur.
Doctor technician conference - Good idea?
John
You can always ask to see any parts removed during service too.
Steve, Host
Check out this website on brakes, brake characteristics, rubbing, overheating and such.
Submitting a new electronic braking system based on old technology, magnetic amplifiers.
Hyraulic fluid, according to the above website, can overheat and boil inside the brake lines creating bubbles.
So, could I substitute brake lines with electrical wiring feeding a magnetic amplifier. The mag amp might cause the caliper to close when opposing "N" and "S" fields are present thus closing the pads against the rotor. Pads are off the rotor by putting a "N" and "N", same pole charges thus repelling the pads keeping them clear of the rotor.
The rotor is a spinning iron wheel, so could I use this as a reverse clutch to stop the vehicle via opposing torque?
The only problem is that magnetic amps need alot of power to create the magnetic fields necessary to stop a vehicle.
Could incorporate a separate alternator to supply all the required power necessary.
How difficult would this be? Mag amps can control large servo's, so how hard would it be to stop a car? I'll draw up a skematic and work out the math.
John
In a magnetic situation, I would need a magnetic field, on each wheel's caliper about the size of a large car to produce that amount of force. If you buy a computer hard drive, it says, keep it way from magnetic sources like monitors or large magnets. So magnetics are not very practical and potentially dangerous to you car's computer.
What I did learn is that "if" a caliper does not have an internal value to equalize the pressure or a faulty equalizing valve, then the hydraulic 1500 psi will be distributed unequally over the rotor. If one caliper plunger sticks out more than the other, so putting pressure to one side of the rotor causing the rotor to bend while its still turning.
Now, you put on the brakes with 1500 psi hydraulic pressure with 500 ft/lbs going to the brake pads via the caliper, but what happens when you release the brakes? Where did that 1500 psi go to? Does it go back to zero psi or is there some residual pressure left which still causes the brake pads to make contact with the rotor. Then I would think that a hydraulic value was bad. Your maintenance dept has on hand a 3000 psi gage and a 1500 psi gage to test the hydraulic pressure going to the calipers. Now, I would ask, when the brakes are released, how much of that remaining pressure can be called out of tolerance? There should be a valve which creates a negative pressure to pull the caliper plungers away from the rotor.
Should there be a dashboard light to indicate higher than normal hydraulic psi under no brake conditions.
John
I don't know how you arrived at that conclusion but it's not the physical size of the field that matters, it's the size and energy requirements of the magnet that matter (assuming you go for an electromagnetic rather than a permanent magnet!).
Technically, magnetic fields continue far out into space but they typically fall off very quickly with distance.
Also, I advise against storing your computer hard drive near your brake pads!
tidester, host
You know that an automatic transmission is another hydraulic unit. So what if one hydraulic unit is fighting with another hydraulic unit, say in putting on the brakes and forcing the automatic transmission to stop, What are the odds something might snap? One of the common elements is the differential. The automatic transmission is pushing the axle to sustain speed while the brakes are trying to stop the axle. Wow, aren't we having fun with physics!
So, until another day at science class, keep learning about those FUBAR brakes from Jeep. If they can't figure it out, then they're out of business.
John
http://www.conti-online.com/generator/www/de/en/cas/cas/themes/products/electron- ic_brake_and_safety_systems/new_ways_in_braking_technologies/emb_0602_en.html
I would have more confidence in motor controlled hydraulic valve rather than a hydraulic pressure valve.
The main computer would have alot more control in braking input and feedback response.
I am reading over this website, and I'm thinking its not the weekend do-it-yourself'r. The addition of accelerometers and the various sensors would have to be aligned just right for maximum performance.
I'm going to find out if someone around here in Southern Ohio or Northern West Virginia sponsors Continental Automotive system.
If Jeep negotiated a contract with Continental to reconfigure their 2007 models or could retro-my 2006, I would seriously consider driving over to my dealership Service Dept and let them have a crack at it.
Thanks!
John
There is one thing I would like to find on 4x4 trucks: it's a disk brake directly mounted onto the transfer case. This would be a great deal for those who have to tow and slow down heavy loads because the 4 wheels can spread the braking effort mechanically, and braking before a set of reduction gears calls for less power because this disk would spin faster.
The hydraulic pressure would imitate the pressure of the other brakes so not to create an unbalance.
Yes, this would be an additional braking system, not to be confused with the braking system already on the truck and hydraulic lines feeding to the trailer's brakes.
This new system opens up a whole new set of possibilites on where to put emergency braking systems because the computer has full access to its function and control.
John
Front end alignments make sure the rotors are exactly 90 degrees, perpendicular to the ground. If the angle is slightly off, you get a gyroscope effect where the rotor wants to move off axis, creating an opposite force against the ball joints/yoke and CV joint.
I would check the front end alignment in the 2002 liberty mentioned above. Wow, too bad Jeep wouldn't just buy your liberty to investigate "what's not suppose to happen!"
Does this make sense?
John
Now, I read that the front Caliper is equiped as a dual plunger or piston model. The rear (by what I've read) is a single piston caliper.
The calipers are essentially a hydraulic valve with multible chambers, depending if its one piston or two. In the maintenance manuals, it mentions to check to see if the hydraulic connections to the caliper or the pistons are leaking.
How often are caliper changed or checked? Air can get into the system from boiling fluid during excessive heat. Can hydraulic fluid degrade chemically under heat stress? Hydraulic valves do not operate properly if the fluid is dirty or contains air pockets. Any fluid under high temperatures expands, thus creating more outward force. This outward force causes the caliper pistons to push out that much more creating unwanted friction against the rotor.
Is there a way to keep a constant pressure between cold fluid and hot fluid?
Are warped rotors "the" cause or a symptom from another source? Rotors are a consumable item, but calipers seemed to be overlooked as a possible suspect. Which should be examined first under situations of premature brake failure?
The problems with Jeep Liberties, I guess only in automatics has existed since 2002. I would assume that after 5 years, someone would have figured it out and fixed it. The last people I want to argue and become frustrated with are the good folks at the Service Dept. Besides putting up with the customers, they have to fix the problems coming from the factory, which shouldn't be their concern.
John
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What's this latest about dealers now correcting the problem under warranty?
Just what exactly causes the problem and what should I tell my dealer?
craig
After seeing year after year the same problems not being addressed for our safety in these vehicles I would gladly sign a petition for a class action lawsuit against Jeep and make them fix these issues. Has anyone done a study yet as to the accidents or fatalies in these vehicles. After 304 dollars and a long drive down the mountain to the dealership.Wondering if they would hold out down the hill. I have the new brakes and turned rotors. Of course not covered as it is after the 12,000 miles... I kept the pads and did feel the warping with my own hands. Of course they can't be turned again since they were so bad. We spend thousands of dollars for a new vehicle and yes we expect to be taken care of by the manufacturer since we the people are the ones who made them who they are today. Jeeps have been around for many decades and the Military have depended on them also. If they had a problem with the Jeep don't we all know that it would have been addressed sooner than later because Jeep would not have wanted to lose that billion dollar contract..We need to unite and make them take this issue seriously for all of our safety and those of our loved ones whom we drive around everyday... It's a shame that we are still paying on some of these vehicles and then must worry constantly about repairs.. Is this not the reason we all bought new to begin with so we could depend on them ...
Waiting for [Jeep] to do the Right Thing in Colorado............
Yes, some brake issues need addressing, but understanding that gearing or jake braking must be an essential part in reducing brake stress.
When I got my 3000 mile check up, I asked about the lube. It appears that many of the "traditional" lube locations have been replaced with non-lube parts. These lube systems were made to be self contained. But, what happens if the integrity of these non-lube systems are compromised? Wow, didn't think about that?
So, from 10,000 feet, one foot on the gas and the other on the brakes and see how far you get on those non-lube systems. They might even explode. Yes, EXPLODE. If its a closed system, no air or water is supposed to enter, or air escape. So put a closed system under extreme heat, and guess what happens?
Can you say 2000 degrees? (radiant heat from a red hot rotor)
If I was a business man, I would heavily invest in an auto repair shop at the bottom of a very large mountain highway or Interstate. I would make a fortune repairing all sorts of brake, bearing, transmission and engine problems from people who think automatic transmissions, power brakes and cruise control eliminates the driver from ever thinking again. As a business man running an auto repair shop, I'm depending on the fact that people are oblivious as to the mechanical aspects of their vehicle.
So, if you notice any lubricant oozing from these non lube or closed system parts, Contact your dealer for an immediate inspection.
So, please downshift whenever possible.
John
the vehicle to any one thinking of buying a new car. Oh, I forgot to say that I have already had to replace the water pump at 3000 miles.
http://www.courtesyparts.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=999- 96-PYMTR
tidester, host
question 1-
anyone had any luck going after Jeep to make good on this?
question 2-
replacing them aftermarket, any suggestions on brands of rotors that are better quality? i don't want to go thru this in another 20K miles.
thanks in advance for your help
Eileen
Farout
tidester, host
The dealership said the problem could be caused by the car "sitting around." While the mileage is low (9,000 per year), the car is driven at least 3 days a week. I know that there have been a lot of problems with Jeep brake rotors, but has anyone heard of this problem and alleged cause?
Michael