Disc Brakes

[Mid-Lake Rock]

I brought my truck into the shop this morning for brake work. I had a caliper fail and there is uneven wear on the pads. Would like some opinions on a few other things they told me.

1. I was informed that the the rotors should be replaced. They were replaced about 13 months (20K) ago. First set lasted approximately 70K. Does this seem unusual? I told them to hold off on this proceedure.

2. They tried to sell me on replacing the caliper that did not fail. Why would I replace it? I did not have this done.

3. Does anyone have any thoughts on getting the brake fluid changed? The truck is at 90K.

Thanks.

[Jeremy airjer W]

Year make and model?

What part of the caliper failed?

Was this the front brakes?

Where the brakes grinding? Did they measure the rotors. If they did than they could give you there measurement and the minumum machine measurement. I like to have at least .025" to .030" in order to turn the rotors. This will usually give me enough room to "turn out" any imperfection and still have a good rotor left when I am done. There are many vehicles where the nominal thickness of the rotor (thickness new) and the minumum machine thickness are very close. Requireing the replacement of the rotor at almost every brake service. I'd still like to hear what there measurements are.

The reason why they replace both calipers is because they are putting on "loaded" calipers. Some of these are sold in pairs now. "Laoded" calipers come with everything, pads, hardware, brackets, slides, etc. If they put on an unloaded caliper most of the time it is a bare caliper with nothing else. If the slides where frozen this will not help anything because that part of the old bracket will have to be reused.

If they did use 1 loaded caliper than they had to charge you for a set of pads and they will have to discard the pads that came with the caliper. Essentailly wasting your money.

The other reason they want to replace them in pairs is to cover themselves from any "warranty" repair and to make sure you get a trouble free brake repair. If the vehicle developes a pull or the caliper that wasn't replaced decides to hang up and destroy the new pads than your out of luck! Another brake service that you get charged for. This may not happen to you but it does happen often and guess what the customer is usually not happy when they get the news!!

I am a big fan of Brake flushes. I said this a few times before but its good info. Brake fluid likes to absorb moisture. At 90k its had plenty of time to do this. Moister will cause not only corrosion but the potential for brake boil over at lower temps. Brake fluid is designed to resist boil over up to 350 to 400 degrees. Water boils at 212 degrees. Guess what happens when you're pulling a load and you have to stop quickly. Your brakes generate a lot of heat. If it boils the moister you get air bubbles which cause you brake pedal to go to the floor which causes the brakes to fail!

[Mid-Lake Rock]

Thanks for the detailed post. It is a 2002 Dodge Dakota. The problem was with the front brakes. I don't know which part of the caliper failed, but it did cause a griding noise. On the work order, it says 901 and 907 for thickness/diameter of the rotors, and machine to 890.

Guy also told me he only did a bleed on the wheel where the caliper was replaced.

Again, thanks for the info!

[Scott K]

You saved your self a few bucks now but maybe gambling for it in the future, it looks like they cut them down to 901, 907, min spec it 890, you may end up with pulsating brakes in the near future, or a brake pull, or another stuck caliper! Or you may not and be fine, they were doing the right thing, more so to cover their butts for come backs. I hope it works out for you!! If I was doing my own I would have done the same thing!

[united jigsticker]

The work order means they mic'ed out at .901" and .907" and were turned to .890" (resurfaced)

Dodge brakes suck, but you stated these are aftermarket rotors.

Unless you ride them puppies, are braking with heavy loads, etc, you should expect a minimum of 40,000 miles before your rotors need help.

Was it the same outfit that did the brakes 20,000 M ago?

[Mid-Lake Rock]

Yes, it was the same shop that put in the after market product. Got 70K out of the original and 20K on the after market. Less stop and go driving than before, which is why I though they'd last longer. The only thing that makes me wonder is the response from the tech. I said how much longer will these rotors last. He said could be six months or could be three years. Huh?

[Justfishing]

The brakes shouldnt fail after 20k. A caliper can hang up for a number of reasons and cause the brakes to fail.

Disc brakes are very simple. There is a piston in the caliper that presses against the brake pads that squeezes the rotor to stop. There is not a spring to pull the piston back. It relies on a slight wobble from the disk to give the pads clearance. A sticking piston or pins will cause the brakes to stick. Usually 1 pad with wear down till it has metal to metal contact. If you keep driving then the rotors will need to be replaced to.

Look at the brake fluid. Is it nice and clear almost like water or is it brown and dirty. If it is brown and dirty it contain a lot of water and contaminants. This can rust out the insides of the brake system. It can lead to calipers and brake pistons that hang up. Also the water in the system can boil when the brakes are under heavy use. The boiling can lead to brake fade. It is recommended that brake fluid be flushed every 2 years.

A lot of places want to change calipers in pairs since the failure of 1 may indicate that the other may fail. If they don't replace both and you are back again then you will be unhappy.

I would be concerned about the brake job 20K ago. If it needed flushing then and they dint advise you do it then it could be their fault. Also the calipers float on pins that need to be lubed and free. If that wasn't properly serviced the brakes can stick.

Also the rear brakes need to be in adjustment. Most of the stopping is done by the front brakes. Many times the back brakes are not adjusted properly and put to much strain on the front. Any time the front brakes are serived the rear brakes should be checked and adjusted.

[fishermn]

Another excellent post... Airjer, from what you have seen, how well do the rotors on Dodge/Chrysler minivans hold up?

[Jeremy airjer W]

The Rotors on the minivans have a problem with pitting on the inside surface. They don't look bad until you try to turn them. The extent of the damage that the pitting has done is prevelent after the first pass of the brake lathe. The pit may only be the size of a dull pencil but it will actually eat away the rotor underneath the surface and can easily be the size of a quarter after the first turn. If there is any sign of pitting the rotor gets replaced!

I've read that this is caused by the rotor not getting hot enough frquently enough to boil of the moisture. I think that there may be some merrit to this as the rotors on the wifes Town and Country have no pitting at all!?!?

As far as pads anything less than a premium line will not last. We tried a less expensive line and 20k was about the average that they lasted.

[Jeremy airjer W]

Quote:

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The work order means they mic'ed out at .901" and .907" and were turned to .890" (resurfaced)

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Actually the .890 is the minimum machine thickness. If the rotor was turned and the end result was thinner than the min. machine spec than the rotor is considered junk. There was .011 and .017 inches left to turn wich is not enough. Most resurfacing is done in a couple of cuts. You can usually tell how its going to go when you zero the lathe. The first pass is a quick cut and I usually start with .003" a side, a total of .006". A minimum of a second cut is usually need to clead up the rest of the rotor. .002 - .003 is my usuall second pass cut, an additional .006" for a total of .012". This will usually get a rotor that is in good shape with no warp completely smooth. A warped rotor could require a third and possibly a fourth for a total of at least .022". That why I like to have a minumum of .025" to work with.