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Uneven rear brake pad wear CRF450 '09-'10


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Ok, I didn't see this exact problem anywhere on here, if I missed it.....sorry.

Lot's of my friends and my own '09 CRF450's have been wearing just the piston pad completely away, and barely touching the inside pad.

After trying everything that one would think would cause this problem; Dry pins, Worn pins, Bent pins, Dry sliders, Bent sliders and Improper installation 😏

Pad set after pad set, I got tired of guessing, so I started to do some research. The entire brake assembly is exactly the same from '05-'10. Well, that is all parts except one, the brake pads have a different part number. Knowing that I had two '05's and one '08 CRF450's, I knew it wasn't any of those parts.

So, I measured the pads and found the holes in the pads are not large enough, mainly the piston pad. That causes the pad to bind on the pins and not return or relax quickly enough. This, all causes the pad to wear a lot faster and much more uneven.

The fix is simple, either buy a aftermarket pad with larger holes. Or, if you are like me and love the stock Honda pads, just lightly drill out the pin holes a few thousands over the pin diameter. They are slotted from the factory, but they are too small on the new part numbers. So, I have been using a standard round hole with perfect results, drill everything together, the pad, heat shield and silencer. No brake drag and totally even pad wear. My brakes work sooooo much better, and are lasting 40% longer.

If you have had this problem, it's not you, it's the pads!😏

Jason

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Your welcome.

It's for the Rear pads. Mainly CRF450 '09-'10, piston side pad problems.

I haven't seen any issues with the fronts, that were from the holes being too small.

I hate these little pains as much as anyone, and I try and find a solution to all of them. If it saves one person from the BS I was going through, then I feel much better about it. One friend uses aftermarket pads now, instead of the stock Honda pads. I just drill them out, the stock pads, it takes less than 2 minutes on a drill press.

Jason

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Since, I’m not the kind of guy to just accept a problem for what it is. I always try and break it down, to a specific cause. The front pads hardly ever have these issues and I do use my 280mm front brakes as much as the stock rear, with no front pad unevenness. (Dang, thats actually a word.😏)

And, when I say that the '09's pads where wearing unevenly. I mean 20% wear on the inside pad, and 100% wear on the outside pad. Metal to metal on the piston pad, barely worn on the inside pad.

All my other bikes, only wore a pad unevenly, if there was a problem, i.e. sticky pins etc. They never wore any one pad exactly the same, as the '09-'10 has been doing for the past year, at an average of 2 hours riding and 2 hours racing per week.

There are over 10 local guys with the same issues, and my friends and I now have our bikes cured.

The drilling really works well for us.😏

Jason

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Good one, I haven't seen any of them, I hope I never do. I have seen my share of them in the past, RM's CR's and CRF's.😏

On aluminum frames, it almost always starts at a weld that penetrated too deep, that left a sharp edge where the crack starts and grows from there.

Do you have a picture of yours? I would like to see it, so I know where to watch mine more closely.

Jason

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Use an organic compound on the static side, and a sintered metallic on the piston side. Or you could grind half of the left side material away so they will end up even. Or, oil up the piston side pad before every ride. Or, you could just not worry about it, and accept it as something you cannot change.

I can't believe how much time I just wasted that I will never get back!

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I noticed that my front brake caliper pads (stock '09) rub on the rotor more than my Yamaha. The Yamaha has a floating rotor while as you know the Honda does not. I do not know if this condition was since new however there is no damage present and everything is in good shape so its either normal or was wrong from the get go. The rubbing is your standard front brake drag but it concerns me as it is significantly more than I am used to. Since you are very experienced with the Honda brakes (specifically the '09 450) then do you think this is normal?

Pins, springs, pads and pistons are in really good shape. I've polished down any mars on the pin and applied proper lube and still it rubs enough to where an equal yank on the wheel allows for about one complete rotation versus 2-3 on the Yamaha. It looks as though the pad does not return fully after brake application leaving a constant drag. Is this normal in your experience (front wheel)?

Thanks.

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Solid State, I do not have that problem with the stock front rotor, or my aftermarket oversized floating front rotor.

I checked today, and I get 2-3 turns or more per spin.

I did have a similar problem in the past, but it was a bad brake line. It got bad enough, that it would stop in the air over jumps.

kwoody51, I have used several different sizes. I ended up with a 6.5mm/.246" drill bit.

On the older style Honda pads ( that didn’t have this problem), the piston side had a hole that were 6.45mm x 7mm, in a oval shape, front to rear being longer. The newer Honda piston pads measure 6.20mm x 7mm, and the heat shield is not aligned as well either. This misalignment causes a ratcheting action, which will not let the pad relax every single time the brake is applied. I noticed several times, that it made the pad crooked and it was stuck on the metal shield. The pins are 6mm in diameter.

Also I made a note to the newer pads, have Nissan stamped in the metal of the pad, under the heat shields. The older pads do not have Nissan stamped into them.

Here is my last recorded picture, taken after last weekends race. The picture is a little off center, but the pads measure out the same thickness with 6 hours on them. No sand and nothing other than prepped dirt/clay tracks.

DSCN0269.jpg

Don't settle for, "It's just the way it is" I've heard this crap for 20 years, about all kinds of stuff and I never pay any attention to it, I correct it!

Jason

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Use an organic compound on the static side, and a sintered metallic on the piston side. Or you could grind half of the left side material away so they will end up even. Or, oil up the piston side pad before every ride. Or, you could just not worry about it, and accept it as something you cannot change.

I can't believe how much time I just wasted that I will never get back!

A little unevenness is expected, but not 60% difference between the two pads. If I'm metal to metal on the piston side, and have a 1mm left on the inside pad. Then, I wouldn't be worried about it! This is the fix that me and my friends have found to be the cure. There is clearly a difference between the two part numbered pads and it is noticeable when you measure the pin holes. Over .030" difference and the shields are misaligned, which I feel is the biggest problem. I have never seen this on any other bike that I have owned out of 30+ bikes, street or dirt.

Jason

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Solid State, I do not have that problem with the stock front rotor, or my aftermarket oversized floating front rotor.

I checked today, and I get 2-3 turns or more per spin.

I did have a similar problem in the past, but it was a bad brake line. It got bad enough, that it would stop in the air over jumps.

Well that's what I thought. Have you ever heard of the master cylinder causing the problem after a crash? I am suspecting that a recent hit to the brake lever caused some damage to the master cylinder piston (which is an internally threaded design - acting like a screw when pushed) or the threaded housing of the master cylinder that the piston turns against. My theory is that the piston does not retract enough now after application causing higher than normal static pressure in the brake line. Since you sound like a guy that digs into details I would be interested in your opinion on this. Do you have advice on how to proceed further? I don't want to waste my time if someone else has been there - done that. I'm also not into ignoring it if it will cause more problems down the line.

Thanks.

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It's hard to say, without having it in my hands. However, sure a crash can bend the push rod or tweak the piston and can cause problems.

If you feel its the master cylinder, take it apart and inspect it. Look for wear spots, or bent parts. A new rod and piston rebuild kit can be purchased for around $30.

How hours are on your bike?

Jason

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Low hours - maybe 15. Is there a MC "rebuild kit" or just purchase individual parts?

If individual parts, seems like the whole unit is about $125. If the piston's threads are somewhat galled then the cylinder it mates with is likely spent as well. I don't think it would be easy to tell without new parts for comparison.

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There is a piston assembly and the push rod is separate.

If the bore is gallled, or even scatched, I would just replace the unit. I have honed them out with ball hones, but you can usually buy a unit for close to the same costs, when you factor in the labor & tools needed. I have all those kinds of tools, and I like to fix them, when they can be fixed.

Jason

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