Disc Brake Wear

[howson]

My after-trip inspections continue!

Some may remember the new pads installed prior to the trip (and bearings) and all the drama associated with that as documented here: https://gdrvowners.com/forum/operati...-along-the-way

I'm trying to measure brake wear without pulling the caliper or pads. (The wheels are obviously off.)

What I did was stick a feeler gauge up where I could plainly see the pad body frame and measured to the disc face. On the front pad I measured 5.664mm. On the rear pad, 7.264mm. So again the outboard pad is wearing faster than the inboard. (There are ~8.8k miles on the new pads.)



According to autochimps.com the front pad has experienced "moderate wear" in what I think is relatively few miles. Even the outer pad is experiencing more wear than I'd expect. (The original brakes on my 2013 Honda Odyssey lasted 80K miles and they still had life in them! The F-350's brakes were replaced at 52K and weren't completely worn out, either.)

Graphic taken from https://autochimps.com/brake-pad-thickness/



Probably not an not apples-to-apples comparison between the trailer and my vehicles, but should the trailer's brakes experience this much wear on the pads after 8K miles?

Is my inspection method even valid?

Thanks for any and all inputs--I do not have a lot of hands-on experience in this area.

Howard

[howson]

So I went out and measured again but used a caliper to measure the feeler gauge to ensure I was being accurate and consistent. I'm fairly confident in the measuring methodology, but I'm still shocked at the wear and hoping for some input and opinions.

[Country Campers]

The only thing that I can think of to check is to make sure that the caliper is sliding easily. There are 2 bolts that hold the caliper in place and these also allow the caliper to slide when pressure is applied. The inside pad is actuated by the piston when it contacts the brake disc the outside pad is then pulled to the disc. When pressure is released the outside pad should "move" slightly away from the disc, inside pad also. If the caliper is sticking in position then it will wear the outside pad more than the inside pad. With the wheel off if you stick a screwdriver or small pry bar between the caliper and inside pad steel plate and pry this should relieve pressure on the system and you can check to see if the caliper moves freely, careful not to damage the disc or pad. If the caliper does not move freely then you should remove the 2 bolts and clean and grease so the caliper slides freely. And you thought disc brakes were going to be trouble free. Definitely easier to work on but still requires maintenance.

Brian

[Guest]

Thanks for any and all inputs--I do not have a lot of hands-on experience in this area.

Howard,

This may be due to the gain being a bit too high. Inside pads almost exclusively will wear at a higher rate than the outside. This is due to the inside pistons having to engage the inside pad on the rotor first which moves the caliper across its pins to engage the outside pads. As much as we would like this activation to be perfect, it rarely is.

Jim

[howson]

Guest -- I was wondering about the gain level. In other words the trailer is doing too much of the work to stop everything.

Country Campers -- I suspect the pins are part of the problem, too. I found them severely corroded last time. After watching several YouTube videos I'm going to replace both the bushings and the slide pins this time. Hopefully the parts are easy to obtain. I'll find out tomorrow at my local auto parts store.

Thanks for the comments, guys.

[Cate&Rob]

Hi Howard,

You have “reinvented” the brake pad feeler gauge which is a fairly common tool.

I would agree with the advice from Brian and Jim . . . and your plan to get the caliper sliding more freely.

Rob

[pengle]

My after-trip inspections continue!

I just replaced my disk brake pads and repacked my wheel bearings. Although I probably could have gotten another couple of thousand miles out of these pads, I was in an RV park where I COULD replace them so I did. Our new trailer came from Indiana with Morryde IS and disk brakes installed. Including the mileage from the factory, my trailer has 21,000 miles on it in 23 months. "Home" is Seattle. But we like to spend time in Florida. Here is a picture of the worn-out pads next to the new pads. I'm sorry that I didn't measure them. As with EVERY other set of disk brakes I've ever replaced, the piston side is always worn more.

[howson]

pengle

Disc brake longevity is not something I can remember discussing here. Thanks for the data point--obviously mine are wearing way to quickly as I suspected.

[Jlawles2]

Howard, if you do not have the original measurement of the pad thickness, you have lost a critical data point.

I might also suggest a https://www.amazon.com/JONMON-Taper-...xpY2s9dHJ1ZQ== for the gap measurement. Simple to use, the marks represent the width at that line. Shove it into the gap of the pad backer or into the inspection groove of the pad and read the line.

Looking at Pat's picture it appears the original pads are of different thickness. By chance did you mix up the pads and put two thin ones on the caliper you are measuring?

[familytruckster4]

Its possible that the manufacturer of the disc brake system favors a softer, faster wearing pad in order to give the rotors a longer life, a pad slap is easier than replacing rotors.
Everything is a compromise.

[howson]

Its possible that the manufacturer of the disc brake system favors a softer, faster wearing pad in order to give the rotors a longer life, a pad slap is easier than replacing rotors.
Everything is a compromise.

I went from the OEM ceramic to a semi-metallic pad when I changed them prior to the trip last summer (when I found the guide pins frozen, apparently never lubed upon initial installation). The braking performance was superior with the semi-metallics, but I think you may be right about them wearing too quickly for the application. I just ordered the OEM Kodiak pads (stupid expensive) and also have guide pins, sleeves, and bushings on the way. Expensive maintenance--hopefully this time it will (finally) be right.

Thanks for the input.

[Jims94vmx]

I went from the OEM ceramic to a semi-metallic pad when I changed them prior to the trip last summer (when I found the guide pins frozen, apparently never lubed upon initial installation). The braking performance was superior with the semi-metallics, but I think you may be right about them wearing too quickly for the application. I just ordered the OEM Kodiak pads (stupid expensive) and also have guide pins, sleeves, and bushings on the way. Expensive maintenance--hopefully this time it will (finally) be right.

Thanks for the input.

Good luck. Take pics and keep us posted. Also, what lube is recommended for the pins?

[Cate&Rob]

The braking performance was superior with the semi-metallics

Hmmm . . . better braking with the significantly less expensive pads would seem like a good deal, even if replacement is more frequent. When you get the slide pin lubrication sorted out, replacing brake pads is an easy part of pulling the hubs for bearing maintenance since you have to remove the calipers anyway. Maybe every second time?

BTW . . . (this may be obvious) but, the caliper slide lubrication goes on the outside of the steel sleeve where the rubber bushing is. Some calipers slide on the bolts, so the bolts are greased, but not these ones. There is a special high temperature grease for brake caliper sildes.

Rob

[howson]

BTW . . . (this may be obvious) but, the caliper slide lubrication goes on the outside of the steel sleeve where the rubber bushing is. Some calipers slide on the bolts, so the bolts are greased, but not these ones. There is a special high temperature grease for brake caliper sildes.

Thank you, Rob--I had no idea. Perhaps that's why the slides froze again because last time I lubricated the pins and not the sleeves?

To make sure I understand, I'm going to lubricate (with the right grease!) the outside of the sleeves as shown in the pic below (arrow pointing to them) NOT the pins (which I've marked with an X). Nothing goes on the pins prior to inserting into the sleeve?

[Cate&Rob]

Hi Howard,

Nothing wrong with a little bit of grease on the bolts (8) to make sure they don’t seize in the sleeves (7) but the sleeves should be polished on the outside and well coated with grease before inserting into clean bushings (4). I also put blue loctite on the tip of the bolt before inserting into the caliper bracket threads.

Rob