Pads? Or Rotors? Or Pads And Rotors?

[l008com]

So back around the start of Winter, my brakes started to pulse and possibly grind. I'm a low milage driver and its a long story but I didn't buy coated rotors, so the pads and rotors are the same age and are about 5 years old. I think it was around 2018 or 2019, before the pandemic.

Also, not working in my favor, is that I don't drive every day. Especially in the Summer, I regularly can go 2-3 days without driving.

So today I was changing my oil and rotating my tires. So with all the wheels off, I took a good look at the brakes. And I'm not really sure what to make of it.

There's a lot of rust, as expected. And some pitting on the rotor brake surface. But it doesn't look THAT bad.

As I'm saving the pictures to upload them to this thread, I'm noticing the rear rotors are warn in a few mm. That, plus the severely worn rear pads, plus the BARELY used front pads... do I have a brake bias problem? How would you fix that? Is there an adjustment for it?

It seems like that would explain the grinding. Would that also explain the pulsing? Or is that separate, and just due to rotor age?

Looking at ll the pictures, I'm not sure if I need, pads, rotors, both, or JUST rear pads and rotors but NOT front pads and rotors?

Thoughts?

Here are four pics of the rotors (not 1 pic per rotor, just 4 random pics):


Here's what's left of the rear pads:


And yet, here is what's left of the front pads:



I'm afraid this forum is going to eat my photos again, so here's the same 6 photos hosted externally, just in case:
https://pasteboard.co/pfSe1AnZIFqg.jpg
https://pasteboard.co/cK1TemOqufRc.jpg
https://pasteboard.co/nDKx24iHXqsA.jpg
https://pasteboard.co/g8KfV75lyOuB.jpg

And the pads, rear followed by front:
https://pasteboard.co/7Ikt3KcDQpbf.jpg
https://pasteboard.co/OFhpPNdo3PXx.jpg

 

[l008com]

Fun fact, I have the same problem (rear pads wearing faster) on my mountain bike. But for a totally different reason. On a bike, your front brake is doing nearly all of the work under heavy breaking. But once you get used to going fast, you don't really brake much down hills. And bikes are light so you generally don't have to brake to stop at the end, you just run out your speed and keep going. So I don't actually do heavy breaking very much. But what I DO do, is speed scrubbing a lot, to get my speed just right. And that I generally do with just my rear brake.

But I don't have two brake pedals on my truck so that is definitely not the same problem

 

[budwich]

You need new calipers on the front... they are seized resulting in most of the stopping going to the back... and of course, discs on the back and probably rotors there also as the existing one will probably cause the rears to wear more rapidly when replaced.

 

[Mooseman]

I'd get new coated rotors all around. That rust is bad and will eventually rust under the friction surface and peel it off. Been there.

Do check all your calipers to be sure the pins are not seized. If the pistons were seized, you'd have smoke from the wheel.

 

[budwich]

Do check all your calipers to be sure the pins are not seized. If the pistons were seized, you'd have smoke from the wheel.

Your calipers on the front are basically seized and are not operating "much". This is causing a "pressure redistribution" such that most of your "stopping pressure" is heading towards the back which are working "fine" except that they are being "over used".

 

[l008com]

How does one check a caliper?

 

[Mike534x]

How does one check a caliper?

The way I've done it was have the truck supported with jack stands on all four corners, and spin each wheel. If it takes muscle to get it to spin, then it's most likely stuck/seized. Other ways would be going off brake pad wear, and if the caliper will "retract" using a brake pad press/spreader tool....or the old school way of using the brake pad and c-clamp. Either way, resistance or it not retracting is a tell tale sign.

If the fronts are stuck, you'll know it if it's wanting to pull to one side when using moderate to hard braking. Becareful with this method, failed control arm bushings will allow the same to happen.

 

[l008com]

I'm still not really sure what to do here. I priced out new pads and rotors at napa and its $333, which isn't too bad. And they are coated rotors this time.

But I'm still not sure how to handle the caliper situation. I'm not sure if it's both fronts that have like-new pads or just one side. I've never bleed brakes before so I'm a little nervous about replacing a caliper on my own. But I definitely want to do the pads and rotors on my own. But once I do the pads and rotors, how can I "test" the calipers to know which are good and which are bad?

Last time I did the brakes, I snapped one of the caliper bolts due to very conflicting torque info on the bolt. So when I replaced it, I went around and removed all the pins on all the calipers and gave them a fresh cleaning and greasing. The brakes were noticeably improved after that.

But if I replace the pads and rotors, clean and regrease all the slides, how will I know if they're working properly? Other than waiting another 5 years then checking the pad wear?

 

[budwich]

As suggested by MIke345x, use a "C" clamp to compress the caliper. You "normally" do this type of technique to remove the old pads anyway. In this case, it is just a test, you only have to tire the tire off to get at the brake unit. Do the "test" (compressing the caliper) on one of the fronts, paying attention to how much effort it takes to compress the caliper a bit. Do the same test on one of the rears. "Compare" your effort. A "frozen" caliper will take more effort to compress than a "free moving" one. Go from your results.

One question would be... how did you change your pads originally? You some how had to compress the caliper FULLY to get the new pads on in the first place.

 

[l008com]

Yes last time I changed the pads and rotors, i compressed the calipers with a C clamp and eerything seemed to go fine.

Is there a chance this IS a case of brake bias configuration and not sticky calipers? I ask because I do tend to be a light braker. That is I brake light and early and I don't usually slam the brakes hard unless some dope pulls out in front of me.

And today when I was driving, as bad as the brakes felt during normal braking, if I hit the brakes really hard, I stopped on a dime no problem. Thats why, even though I don't really know much beyond the basics of how brakes works, it makes me wonder if too much rear bias plus my typically very light braking meant I was mostly just braking with the rear only even though the fronts would be fine?
Or is that all just wishful thinking?

 

[budwich]

I don't know much more in this area. My suggestions were based on the visuals that you provided. The suggested tests will add "data" to that. Just because things were "good" when you did the install "5 years" ago doesn't mean they are good there after. That's called "broke".
In normal braking, one expects more stopping pressure to be exerted on the front since the moment causes things to be "forward". There is valving function (proportional / equalizer) involved so that the system doesn't get impacted by the significant "dip forward" by having the fronts act more than the rears. I think that is part of the master cylinder, but not sure. I don't believe there is any adjustments but I don't know.... others will comment. ABS on newer systems gets involved and that's where I stop...

From my experience, most people usually find themselves replacing their front discs more often than the rears over time.

 

[l008com]

From my experience, most people usually find themselves replacing their front discs more often than the rears over time.

Yeah and my front pads, after 5 years, look basically new. Although I'm going by just one side. I was in a rush when I did my oil change, I wish I had more time to poke around all four brakes while I had the whole truck up on jackstands. Ugh. Hopefully some day soon I'll have time to take everything apart again.

 

[Mooseman]

I'd just replace the rear pads and rotors with quality parts, regrease the pins. It's possible the pitting on the rear rotors ate through the pads. The fronts I'd pull the calipers, make sure the pins are free and regrease them, knock off the rust from the rotors and put it all back together. Don't use a wire brush or anything on the friction surfaces of the rotors.