Rear Brakes - Anybody Seen This Before?

[JW113]

So my rear brake started making noise last weekend. Before then did not notice any sound. Took a look tonight, the top edge of the disk is chewed up:
[attach=0]

I took the caliper off, and bingo:
[attach=1]

So the rear brake pad pin was rubbing on the disk??? How can that be?

The front mounting pins in the bracket are pretty tight, not much up/down movement in the caliper at the rear, just loose enough to let the caliper float. And I have one of those anti-rattle springs pushing the caliper up away from the swing arm. Has to be one wicked mechanical interference for the disk to cut a notch that deep in the brake pad pin. But how could that happen?


The boomerang caliper bracket is chrome plated. Factory is black paint, yes? So.... aftermarket, yes? Possibility the two big holes in the front to mount the caliper are not in the correct location, letting the caliper sit too low in the back?

Yikes. I have a true stock boomerang, in rough condition needs to be repainted, but could toss that on to see if that is the issue.

Anybody seen this before?

-JW

[Ohio HD]

Pretty common actually. Fellers used to stick these under the caliper to try and stop it.


http://www.cas4.com/brakes/Brackets-Master_Cylinders-Hardware/springbracket2.jpg

[Dogbone45ACP]

The holes for the pins that anchor the brake pads can also get worn out of round. That and wear on the pins that support the caliper and things rub.

[76shuvlinoff]

Yeah all new pins and bushing where possible can compensate for a lot of wear but not all of it. A chromed caliper mount is not factory (as far as I know) and is a wild card.

There are different diameter rear rotors but I don't believe you can mix them up. For shovels I think it's 10" and 11.5" or is it 10.5" and 11"?  and in that case I suppose you might be able to confuse them.

[JW113]

Pretty common actually. Fellers used to stick these under the caliper to try and stop it.

Yep, and I have one on it. Didn't help.

Dogbone: "The holes for the pins that anchor the brake pads can also get worn out of round. "

Yeah I was checking that out just now. The holes in the caliper that's on the bike are indeed pretty 'oversized' compared to the pins. Definitely have some wear going on there.

Mark: "Yeah all new pins and bushing where possible can compensate for a lot of wear but not all of it."

Yep, and this one has them. New pins, new bushings all around. And still.

Am also wondering, the disk itself came from J&P. Any chance that the disk is just a hair too big in diameter? A quick and dirty "fix" would be to lift the rear wheel, fire it up and put it in 1st and take an angle grinder to the disk!

So I think that something (fate, budda, my guardian devil) is telling me it's time to think about a better brake set up. As much as I hate to loose the wicked cool 10" banana, might just have to drop something else on there until I can figure out how to make the banana work right. Hell, I got all the parts on the shelf to put a twin cam roadking rear brake on it, guess I have my weekend project lined up.

In the mean time, think I'll start toying with how to "blueprint" a banana caliper, install bronze bushings for the brake pad pin bores to repair the worn out holes.

-JW

[76shuvlinoff]

 JW, after 22 years with my 76 I don't let upgrades and modifications disturb my sleep. I just don't make mods that involve cutting things up and then I kid myself I will put it back to stock someday. I have shelves of "stuff" in the basement to attest to that.    If you want to turn that JP rotor down what are you going to lose?

Mark

[Tynker]

Pretty common actually. Fellers used to stick these under the caliper to try and stop it.


http://www.cas4.com/brakes/Brackets-Master_Cylinders-Hardware/springbracket2.jpg

Before that little ditty, we used a valve spring welded to a piece of angle iron. It worked good, and was cheap fix.

[JW113]

Good point Mark. 10 minutes with a grinder and voila! Fixed!


Let's see, if this were to happen out in BumFreak Wyoming, what would you do? That. What else? And most likely not fix it after you got back home until something broke and you had to.

I'm in!!

-JW

[76shuvlinoff]

I dunno why the hell I woke up thinking about this..... 

Since maybe this is an aftermarket mount... Is it possible the axle location on the mount is not centered on the arc of the caliper? Would adjusting the length of the support strap change the clearance? 

Mark

[BKACHE]

This is one of the reasons I went with the welded tab onto the swingarm and the 2004 or so rear brake.
It is shocking the first few times that the rear tires brake will actually slow the bike down vs the old banana caliper. I have one is in the swap meet.

[Racepres]

This is one of the reasons I went with the welded tab onto the swingarm and the 2004 or so rear brake.
It is shocking the first few times that the rear tires brake will actually slow the bike down vs the old banana caliper. I have one is in the swap meet.

Either of the Bananas on my Shovel will lock up the tire at will [front or rear]
But, I keep the bushings and Pins replaced, good Pads, and proper alignment...
It's called "Maintenance".

[BKACHE]

Ya

[JW113]

Racepres: "But, I keep the bushings and Pins replaced, good Pads, and proper alignment...
It's called "Maintenance".

Mine works just fine too. The problem is the holes in the caliper castings that hold the two brake pad pins are SHOT. So the rear pin is riding on the disk. Nothing to maintenance other than throw the caliper away and try to find another one in better shape.

OR buy China made one from V-Tiwan.

OR try to figure out how to bush those holes for the pad pins, and then continue to deal with the mount pins and bushings with will wear out with use.

OR adapt a late style and forget any more maintenance other then replacing worn out brake pads....

So many choices!


-JW

[fourthgear]

  Performance Machine

[Racepres]

  Performance Machine

Good Stuff...but, I prefer the Older GMA...

[prodrag1320]

I put willwoods on my `76,nice,inexpensive calipers

[Racepres]

I put willwoods on my `76,nice,inexpensive calipers

Oh Yea...Forgot about Willwoods....Yeas, Good Stuff for small $$

[prodrag1320]

Back when I put them on,they where 98.00 each,just had to make a hanger

[Racepres]

Back when I put them on,they where 98.00 each,just had to make a hanger

LOL
A "Deal Breaker" for Most these days I'm afraid.....

[Old Crow]

Back when I put them on,they where 98.00 each,just had to make a hanger

LOL
A "Deal Breaker" for Most these days I'm afraid.....

But for the machine shop challenged, there's always FabKevin.  I hear he makes some awesome brackets.

[JW113]

Solved!!!

So here was the problem:
[attach=0]

This POS chrome plated garbage from V-Tiwan??? or where ever was the culprit. I put an old rusty stock boomerang on, and voila. Tons of clearance between the brake pad pins and the rotor. Yea, same old Chinese proverb at work here: "close enough is good enough". Bologna!!!  Bologna!!! Yo Tedd, ESAD!!!

So I keep telling you guys, don't buy this V-Tiwan made garbage.


Back to braking as it should be...

-JW

[76shuvlinoff]

 
Good deal!

[rageglide]

Great, glad you got it fixed dude.    Did you compare the brackets to see what was different?

[dirtymike]

The Asian community reverse engineer these parts. The problem is they use old wore out parts and the tolerance is out from the starting point. They also use inferior steel that usually doesn't last long. The OEM parts are hard to find and usually wore out so alot of us have no where to go. Dirty

[JW113]

Great, glad you got it fixed dude.    Did you compare the brackets to see what was different?

Not yet. I only put the stock boomerang on, mounted the caliper w/o brake pads, and took an eyeball to it. Chrome bracket, hard core mechanical interference and grinding on the disk. Stock bracket, looks to be at least 1/8" or more clearance between the brake pad pins and disk. Now I need to pull it apart again, clean up and paint that bracket, and put it back. When I take it off, will compare to the POS one & report with what I find.

BTW, I came this -><- close to ordering up a Fab Kevin Tokico caliper and bracket. Held off until I could find root cause. Now will give the banana another day in the sun before deciding if it needs to go or not. Hoping not...

-JW