Disc Brake Wear

[Jlawles2]

howson Howard, 2 things I have learned doing brake work over the years. Good performance sacrifices life, good life sacrifices performance. There is a happy medium in there somewhere, you just need to find it. Personally I would keep running those softer pads until they are gone.

One other thing that affects performance is bedding of the pads properly. The ceramic bedding may actually be hurting the life of the semi metallic pads. That's why they say you should turn rotors every time you do brakes (not that I abide by this).

[howson]

Cate&Rob -- still waiting for the new pads, but picked up what I hope is a suitable sub for the grease. (They didn't have the exact grease recommended in post 13.) Any issue I'm not aware of or should what I bought work just fine?



BTW...while looking for more information on the Kodiak 225 disc brake setup (and what I thought were "slide pins") I watched YouTube after YouTube video showing mechanics lubricating the "slide pin". Knowing you well enough, I knew there was a reason for the statement to lubricate the interface between the guide bolt sleeve and rubber bushing, not what I'd think was the "slide pin" (Kodiak calls it a "guide pin"). Not finding anything applicable (at least not on YouTube) I looked through the Kodiak instruction manual again. Son of a gun...look at the pic at the end of the document!


If all else fails, read the freakin' manual, eh?

[Cate&Rob]

howson

I think you have the plan! The grease you have should be fine. I go one more step and polish the outside of the sleeve and the same diameter area under the head of the bolt (600 grit paper) to make sure that the bushing slides smoothly. Also (mentioned earlier) . . . a small amount of that same grease on the bolt will make sure that it is not seized inside the sleeve on the next disassembly. Some blue loctite on the threads of the bolt is also a good idea.

Rob

[howson]

Got the curbside brakes done today. All four of the guide bolts, guide bolt sleeves, and bushings looked fine. Most likely a waste of money replacing these parts (sigh).

Grease was applied per the manual with just a very, very light smear across the bolt. The new bolts already had loctite on them. Bolts were torqued to 40 ft lbs per the Kodiak manual.

What I did find that mystifies me is the very unusual "lip" worn into some of the pads. The visual indication is the pad was not seated correctly so the outside edge of the pad never contacted the rotor (thus it didn't wear). I don't know how that can be done...but the pad doesn't lie.



In response to what I found, upon close inspection there is movement possible from front to rear with the pad in the caliper, so I pulled them as far forward in the caliper (closer to the center of the hub) as possible and then activated the brakes to seat them in place. Will this take care of the weird wear pattern? Time will tell. (I'm confounded these brakes as so "hard" to work on--my Goldwing's disc brakes are a breeze to service.)

A couple of notes for future reference:

Pads installed are from Advance Auto Parts and are part number MKD289. These are semi-metallic pads. (Yes, I changed my mind again. I calculated it would be cheaper to replace the pads more often--especially if this wear pattern continues.)

Edited the following paragraph after feedback from @Cate&Rob in a subsequent post.

The starting thickness of new (pad closest to me--the one with the wear indicator) is 16/64". The wear indicator will hit the rotor after ~13/64" of wear (at least according to my unscientific measurement). One of these pads I removed had 2/64" (!). I wonder if I'd even hear a brake squeal when the indicator is hitting the rotor? Somehow I doubt it.

[Cate&Rob]

Hi Howard,

I’m just trying to piece together all the parts of this . . . if the outside pad was down to 2/64”, the inside pad should have been long gone. Inside pads always wear faster than outside pads because they apply first and then pull in the outside pad. I think something is hanging up the movement of the caliper body and not allowing the outside pad to release from the rotor. (This can’t be helping your fuel mileage).

Can you assemble the caliper to the bracket without the pads? You should be able to move the caliper back and forth across the bushings, by hand, without too much effort.

If everything is back together, use your infrared temperature gun on the outer pads after driving for a while. If one is hanging up, it will be hotter than the others.

Rob

[howson]

Hi Howard,

I’m just trying to piece together all the parts of this . . . if the outside pad was down to 2/64”, the inside pad should have been long gone. Inside pads always wear faster than outside pads because they apply first and then pull in the outside pad. I think something is hanging up the movement of the caliper body and not allowing the outside pad to release from the rotor. (This can’t be helping your fuel mileage).

Can you assemble the caliper to the bracket without the pads? You should be able to move the caliper back and forth across the bushings, by hand, without too much effort.

If everything is back together, use your infrared temperature gun on the outer pads after driving for a while. If one is hanging up, it will be hotter than the others.

Rob

25 Oct: Edited below for clarity.
The pad closest to me was almost worn out. This is the pad with the wear indicator. The pad closest to the center of the camper was almost new.

It will be awhile before I actually do a "tow test". What I don't understand is what would cause it to hang up? There's nothing obvious, at least to these untrained eyes.

[Cate&Rob]

Hi Howard,

This is making more sense. “Inside” is normally towards the centreline of the vehicle (the brake piston side). This is the pad that wears the most and where the wear indicator tab will be. So, the reverse of the inside/outside noted in your diagram.

This still doesn’t explain the excessive wear on your brake pads. I have something like 15,000 miles on mine and at this year’s bearing service, I noted that the pads were about “half worn” (I didn’t take measurements). I have the trailer brake gain set for what I would call “aggressive” trailer braking. I feel the trailer pulling back on the truck during a hard brake apply. I can’t imagine that you have your trailer brake gain greater than this. I think that something may be causing your trailer brakes to not fully release.

What I would try . . . Find a gentle paved downward slope. Back up a short distance (should help to fully release the trailer brakes). Use just the truck parking brake to stop the rig and, put the truck in neutral. Release the parking brake and the rig should roll slowly forward down the hill. Manually apply the trailer brakes to stop the rig. Release the trailer brakes and the rig should begin to roll again . . . if the trailer brakes are releasing properly.

Rob

[howson]

Cate&Rob -- The wear indicator is on the pad that is nearest to me (so the outside?). The "far" pad (that's against the brake piston or "inside") looks almost new.

Thanks for the suggestion on checking for proper brake release.

[Guest]

Howard,

The inside of the rotor is toward the center of the rig where the hand writing is backwards on your illustration. So folks are on the same page. Are there signs of rust on the rotors or do you have stainless rotors? It looks like with the proper high temp brake grease you will be fine. I've seen pads with the edges wore from a band of rust on the rotor and also where a small stone was lodged in the caliper. In a vehicle you would have heard this but on a trailer it would be unlikely to hear it.

Jim

[Cate&Rob]

howson Hi Howard,

In my experience, the brake wear tab is on the inner (piston side) pad, because this pad usually wears faster. (See attached "generic" picture grabbed from the internet) I don't recall my trailer brake pads even having these wear tabs . . . so, I can't offer an actual picture. If your "piston side" pad looks almost new and the "other side" pad is well worn, this indicates that the pins/sleeves/bushings that allow the caliper to float in and out, is jamming and not releasing the pad from the disc when hydraulic pressure is removed from the piston and it relaxes away from the disc.

Rob

[howson]

For clarity, when using the term "wear indicator" the reference is NOT to the groove in the inside pad. (These grooves are what I can see looking at my motorcycle's pads.)




The "Wear Indicator" reference on the trailer's brakes is to the metal tang attached to the outside pad. I assume that when the metal wear indicator hits the rotor (if I could hear the "screech") that would be my cue to change the pads.

[howson]

In my experience, the brake wear tab is on the inner (piston side) pad, because this pad usually wears faster.

As I thought about it more last night I wondered if that wasn't the genesis of the confusion. As soon as I posted the pics above about the wear indicator I saw your response confirming it.

As always, greatly value your input, Rob. (You too, Guest !)

Howard

[Cate&Rob]

howson . . . the more that I think about this . . . I would suggest attaching the caliper without pads and making sure that it slides freely in and out on the greased sleeves and bushings. Be careful not to apply hydraulic pressure during this exercise !

Rob

[Guest]

I know this sounds crazy but are their hydraulic hoses at each caliper? I've seen these aftermarket kits installed with the metal hydraulic lines rigidly connected from the frame to the calipers which would inhibit the caliper to slide on the pins.

Jim

[Jlawles2]

howson Howard, let me pull some old school knowledge out of the grey matter here.

1 - wear on pads indicate something needs to be adjusted. Be it the bushing or bolts not allowing something to slide, routing of the hoses, etc.
2 - The tabs on the back of those pads are used to "tune" placement and ensure the pad does not "walk" away from the piston. This also contributes to noise. Using a "hammer" (because brute force is much faster) the tab radial gap can be altered to ensure the pads are placed properly radially.
3 - The tabs (again) are also used to control circumferential movement of the pads in the caliper. Back to the brute force method again, this time the tabs can be used to stop angular movement in the caliper. Spread or tighten the space between tabs on the back of the pad following rotation to ensure they do not "move" causing strange wear and possibly lack of performance.
4 - Double check for AIR in the system. New method I found for doing auto is to crack the bleeder and compress the piston (one man bleeding going on here) so I can control the flow. Air compresses and will hold pressure against the pads. Not certain on how these are valved, but it is possible that the master cylinder is "PULLING" the fluid slightly back resulting in a gap on the piston side (not common as it leads to other issues). Yes I have seen something similar on non automotive applications.

I know it's a bit long winded and will probably bring a lot of controversy about bending the tabs, but that's how I was taught by DAD many many moons ago when we had issues with noises and other strange things. Use your best judgement with my OPINION and EXPERIENCE of adjusting pads.