You should change pads and rotors at the same time. Using old worn rotors is a bad idea.

 

This is absolutely incorrect! Bad advice.
Unless the rotors are severely worn, damaged or warped there is no reason to replace them.

 

But, bit confused as to what I need.

You need to watch good instructional videos about how to do a brake job.

 

I have done brakes on multiple vehicles- It's more a question of which parts. Because of the likelihood of returns, O'reilly works best. But, huge difference in prices, some difference in specs.

 

My highly scientific rotor test is running a thumbnail across it while examining it with calibrated eyeballs. If there are not any large ridges or valleys(and assuming there were no warped rotor symptoms), I slap on new pads. If there are, or a backing plate has made contact with the rotor it gets turned. There are clear and present mic minimums for rotor thicknesses....most rotors can be turned twice before falling below those minimums, turning costs less than $20 here, but it is a trip to town for me. The last rotor I bought(JKU rear)was around $60, and I didn't have to inspect, I could hear the backing plate and rotor grinding themselves into metal shavings.

Pads and rotors are all about surface area. Some believe that a moderately grooved rotor gives a fractional extra bit of surface area over a new rotor. Within a few good stops, a new pad will conform to the old rotors grooves. Either way, I have never had what I would call early pad failure following the procedure above.

I posted this before, last year, the JKU was at the dealer for warranty work. They did a "100 point inspection" & said my front rotors were bad and quoted the brake job at $450. I went home and pulled the front tires off. The rotors were in great shape, so new pads and off we went for <$65.

 

Several years ago I tried to get some rotors turned (not for a Promaster) and every shop I went to or called laughed and said no one does that anymore 😩
I think new Chinese ones are so cheap it’s not even worth it unless you can do it yourself.

 

(in a Ron White voice) "Just call me.....Old School" 🤑

I wonder if Kip has a rotor turning machine??

 

Skipping over the brake drum years...brake shops will almost always advise for new rotors because why not, it isn't their wallet. If you let pad wear go too long then of course replace the rotors. I've only had to replace rotors when warped, and once when a pad wore down at an odd angle and scored the rotor along one side, otherwise replacing the pads has always performed as well as new brakes. @Kip-on-truckin seems to agree.

 

Personally, I’ve just replaced the pads only on many vehicles but only when the rotors appear to be in excellent condition. Promaster rotors are certainly good for 75k miles or more (if they show no damage and minimal wear). I wouldn’t hesitate to only change the pads. Having said that, I’ve done many brake jobs in my time and I‘m experienced in what is acceptable and what is not. If you are inexperienced it makes sense to change both pads and rotors if unsure.

 

I don’t like internet arguments but I agree with @Motor7 here. I am not a mechanic but had 2 family members who were. I think mechanics nowadays don’t have the same mentality of older mechanics who actually could fix things. I have had great mechanics in my life, what made them great was:
1 I was allowed to actually talk to the mechanic and not some service tech who can’t spell spark plug
2 they had solid reasoning and didn’t always rely on a computer code
3 they came with options instead of suggesting all the parts to change
4 they care about returning customers and took some pride in their knowledge and work
Now I can’t find a good mechanic anywhere and my father in law is 87 so, no, I won’t ask him. If I lived closer I would love to bring my van to @Kip-on-truckin as he seems to fit my idea of a good mechanic.

 

Wow a lot of talk about rotors. I'm thinking about stopping the 7,500lb beast in the Rockies. The brakes on the PM are pretty good quality. Get that or better, if you do replace rotors. You might be taking off a better quality part, for something not as good. Also look at Rockhall.com, they have a good vented rotor starting at $25, on close-out. But I would reuse a good OEM vented rotor, vise installing a new cheap solid rotor.

 

Yeah, it's a baseless argument to say you should 'always' replace rotors when doing pads. If there's no damage why would you throw out a perfectly good set of rotors? Out of fear? On a whim? Not only is that a waste of money but a waste of resources.

 

I've been doing disc brakes for 25-30 years. Seemed like whenever I tried to cheap out and just do the pads, it wasn't long until I regretted my decision because the rotors would get warped. I'm not sure if it was related to the age of the rotors or a result of the new pads bedding in, but I seem to recall it happening more than once.

The only thing I hate more than overspending is doing the same job twice because I cheaped out the first time. Now, I always just buy new rotors and think of all the money I'm saving by not have the shop do it.

 

I've been doing disc brakes for 25-30 years. Seemed like whenever I tried to cheap out and just do the pads, it wasn't long until I regretted my decision because the rotors would get warped. I'm not sure if it was related to the age of the rotors or a result of the new pads bedding in, but I seem to recall it happening more than once.

"I've been doing disc brakes for 25-30 years." Professionally or occasionally?

The question is "What happened?"
You had rotors that were working fine, stopping properly and seemingly not warped.
Then you put on new pads and all of a sudden the rotors decide to warp?
Did the new pads overheat the rotors because they are new?
Did the new pads somehow wear metal off only in some areas of the rotor?

Rotors don't just magically warp because new pads were installed.

I suspect that the rotor and or hub mating surfaces have some rust/deposits on them and the rotor didn't seat/sit perfectly on the hub causing runout. This can cause pedal pulsation. Aggressive pad material can then wear the rotors unevenly. There is also the possibility of build up of friction material on the rotor which can cause a warped rotor "feeling".

If the sliders/pins are not properly lubricated and moving freely every time pads are installed then they can drag and cause excessive heat and irregular wear.

The "seats" the clips sit in must be cleaned down to bare metal. If there is a build up of material under the clip seat then the pads can't move freely so they will drag, again causing excess heat and wear.

If you are using a hammer, clamp or excessive force to get the pads in place you are doing it wrong!

The mating surfaces of the hub and rotor/drum must be absolutely clean and free of and deposits that could prevent the rotor/drum from seating perfectly.

There is a big difference between installing a set of pads properly and just slapping on some pads when you don't know the proper procedures. Knowing how to undo some bolts and put them back in doesn't mean you will get perfect result from your brake job/pad change.
I apologize if this sound harsh but there are a lot of amateurs giving advice about things they are not qualified for and it causes a lot of problems.

You don't want to learn from a youtuber that just did his first brake job.
You want to learn from someone who has the capacity to understand the systems/functions, was trained by a pro and has done a ton of brake jobs including the rework of jobs done improperly by diyers. Not me exactly but close, I have decades of related experience in more complex mechanical applications.

Good luck guys. Keep the rubber down.

 

Not mentioned, but I've always used basic and inexpensive organic pads instead of the expensive ceramic and sintered metal pads that are heavily advertised. These days you really have to hunt to find the cheaper organic pads.

I like the way organic pads respond to the pedal, don't care about the brake dust, and they cause almost zero wear on the brake disks. I've replaced pads about 7 times on the Legacy Subaru, and the disks show little wear (around 0.050" thickness lost), and are smooth and in nice condition.

I say let the pads take the punishment. They are cheap and far easier to replace than disks.

 

I guess if one rides the brakes for a long period of time something is going to give. I think the way we all drive differ quite much. I see so many people riding the brakes down long hills here in Colorado and it scares me. We had a very bad accident a few years ago in Denver where a semi lost all brakes. I wouldn’t blame the driver as much as the company and in general the way some people seem to get their driver’s licenses in the cereal box.

 

I've driven just about every type of heavy vehicle in my day. Box trucks, dump trucks, Isuzus, not to mention trailers and all types of equipment. I've driven without fan belts, or a wheel, cooked plenty o brakes and boiled trannys too, it happens. I have a clean driving record. I've wheelied dumpers and am certified in going sideways. I driven everything overloaded and have the weight slips to prove. I deeply enjoy flogging large vehicles and encourage others to learn the art, it's not reserved for English sports cars or overly enthused Miata owners. I find the humble passenger vehicle anemic to drive and can't imagine having an issue with brakes as I could simply drag my size 12's to do the job if needed. Things are usually going so smooth for me on the road I use windshield time to pet my kitty.

Brakes can handle serious torture before they give out. I just can't get excited by the masses of people that shorten the lifespan of their brakes or rev out their engines instead of using brakes. Think of every soccer mom or nervous Nelly that rides them across town for no reason. Or that person that has it engrained in their head to hit that pothole vs avoiding because that's how they were taught to drive. People suck at driving that's the problem, and we don't need more internet experts to unpack it.😁

 

On top of possible uneven greasing/sliding of caliper pins, there is also a break-in period (as with new car brakes) where new pads should be used as lightly as possible until fully seated. Also, the wheels act as a heat sinks for calipers, so unevenly torqued wheel studs can cause uneven temperature distribution across a rotor that in extreme situations (heavy usage on long downhills) can cause it to warp. About 12 years ago I was driving a 2009 Honda Civic down the Saluda grade on I-26 in a cold rain. My brakes were likely already hotter than they should have been when a semi cut me off to where I had to hit them hard, swerve, and hit a puddle on the shoulder that splashed cold water everywhere including my very hot (factory) front rotors, which warped them instantly.

 

I've never replaced the rotors on any vehicle I've ever owned if they were not warped, worn beyond specs, or otherwise damaged. Not on my motorcycles, cars, trucks, vans, or trailers and I've never had any issues with my brakes due to the rotors. I've had master cylinder issues, bad calipers, and even ABS problems, but the solid piece of rotating steel that was still within proper specs.... no once in millions of miles.

 

Ive reused rotors that had metal to metal contact before, it was worth the two years extra I got out of them at the expense of a $40 pad set. Sure it wasn't great, they looked a little rough too and was noticeable to someone who could sense the subtle loss of performance, but otherwise fine and passed inspection. Meh.

 

When young with limited funds I scrounged brake parts from junkyard wrecks, all shoes and drums back then and even the whole kingpin steering assembly for my '64 Beetle that had over 112K miles on it. I drew the line at the master cylinder and bought a 'new' rebuild kit for it. ;-) Steered and stopped like a dream afterward.

 

This caliper and pads & rotor on our 33' Fleetwood Bounder might have got a tad hot:

 

I’m closing this thread. Everyone has had an opportunity to state their position and while we don’t all agree all the time, name calling and insults do not benefit anyone.