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PostPosted: Thu Feb 08, 2018 1:02 pm 
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Turbo EFI
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Joined: Wed Nov 23, 2011 11:07 am
Posts: 2125
Location: SF Bay Area
Car Model: 67 dart 2 door hardtop
I have a 67 dart 2 door hardtop. Disc brakes in front, no issues, rear drums 10 x 2.5", 8.75 rear end. My rear passenger side brake makes this scraping or rubbing rotational noise when it's hot outside. In the morning when it's cool, nothing. It doesn't appear to depend on how long I've driven it. For example, if I start out cold and drive it for 10 miles, no noise during the whole trip. Hours later, when it's a hot day, I'll take it out and the noise is really prevalent. I had it to the brake shop, they said my drum was warped a bit and they turned it. When I left the shop, no noise. Later, noise is there. It seems to come and go, but I did notice on hot days it is more common than on cold days, so seems like a material expansion issue, something rubbing. NOTE: the noise is while I'm driving, when I brake, even slightly, the noise goes away.

The pads and drums are both fairly new, maybe a 1000 miles on them. I haven't looked since the shop turned the drums. I'll pull the wheel and inspect for signs of abrasion, but in the meantime...anyone ever had this issue? Thoughts?

Thanks all,

Brian

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PostPosted: Thu Feb 08, 2018 1:39 pm 
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Inspect carefully for rub marks. Possibly drum to backing plate area.

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PostPosted: Thu Feb 08, 2018 2:11 pm 
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Turbo EFI
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Location: SF Bay Area
Car Model: 67 dart 2 door hardtop
I'll check carefully for any scrapes or rub marks. b

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PostPosted: Sat Feb 10, 2018 6:52 pm 
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Turbo EFI
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Joined: Wed Nov 23, 2011 11:07 am
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Location: SF Bay Area
Car Model: 67 dart 2 door hardtop
Didn't have time today, so I took the Dart to the shop. They said they could not find anything that looked like something rubbing or scraping, pads were good, drum good, all in order. When I drove it home, I heard no noise.

They did suggest that it might be the axle bearing. When I put the 8 3/4 in, I had a shop put in new green bearings and put a new clutch pack in the posi, and install NOS 2.76 ring and pinion. That was only a few years back, I've changed the gear oil after running the new gears for a few thousand miles. It's hard to believe it's the bearing, but....

Would an axle bearing noise come and go, and disappear when I hit the brake? Seems like a brake issue to me.

Brian

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PostPosted: Tue Feb 13, 2018 10:47 am 
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Turbo EFI
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Location: SF Bay Area
Car Model: 67 dart 2 door hardtop
Noise is back. I'll have to pull the wheel an inspect myself; I have a hard time believing this isn't brake related, but one never knows. b

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PostPosted: Tue Feb 13, 2018 12:54 pm 
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Joined: Sat Oct 19, 2002 12:06 pm
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Location: Silver Springs, Fl.
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When the green bearings were installed, was the thrust button, in the center section removed? There is one style of green bearing, that requires that to be removed, or the axles shortened slightly.

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PostPosted: Tue Feb 13, 2018 1:05 pm 
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Joined: Mon Oct 21, 2002 11:08 am
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Location: Blacksburg, VA
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This might be a bearing starting to go bad due to exactly what Charlie said. If you do not do that (remove block OR space the axles back slightly from the backing plates OR shorten the axles slightly), then you will be hugely side loading the axle bearings and they will wear out. I had this on one 8.75" where someone did not do the mod(s) required. As an easy fix, I put 0.050" thick washers between the axle flange and the backing plate and filled the gaps with RTV. Never had a problem. The better fix is to remove the thrust block or grind the end of the axles down. When you unbolt the axles you should be able to tell that the plates/flanges were distorting somewhat to get the nuts down tight.

I believe this is the main origin of the saying that "green bearings are not good for handling/autoX or side loading applications". Probably a bunch of people made the above goof and then the bearings failed.

Lou

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PostPosted: Tue Feb 13, 2018 2:31 pm 
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See this info on the green bearings. http://www.doctordiff.com/blog/tech-inf ... -bearings/

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PostPosted: Tue Feb 13, 2018 2:40 pm 
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Looks like DoctorDiff agrees with me. The really fast road race and circletrack/NASCAR guys (150+ MPH in heavy cars) convert to a full floater rear axle bearing, but that is bigger bucks, heavier, more complex...

Lou

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PostPosted: Wed Feb 14, 2018 8:59 pm 
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Turbo EFI
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Location: SF Bay Area
Car Model: 67 dart 2 door hardtop
Mine didn't have the thrust button and it appeared that my axles had been previously modified, ground and finished at the ends. I don't think it's the bearing. Reality check: if it were the bearing, would it not make the noise all the time? This noise comes and goes, seems to be more prevalent when hot over cold temps. Also, if it were the bearing, would the sound stop when I hit the brakes? Doesn't seem likely but maybe I'm missing something totally logical there.

I'll have to pull the wheel and check the brake assembly myself, if indeed there is absolutely no sign of anything touching/rubbing, then I'll start to believe it's the bearing.

Brian

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PostPosted: Thu Feb 15, 2018 12:47 pm 
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Turbo EFI
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Location: SF Bay Area
Car Model: 67 dart 2 door hardtop
I'll pull the wheel and check the brakes this weekend. If I don't find anything, then I'll check out the axle flanges for distortion, maybe pull the axle and check the bearings. I gave the axles, chunk and housing to the guy who installed the green bearings and assembled it for me, who knows, maybe he stuck a thrust button in there? That was at least 3 years ago, you'd think I would have heard something sooner, perhaps not.

brian

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PostPosted: Thu Feb 15, 2018 12:51 pm 
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Turbo EFI
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Location: SF Bay Area
Car Model: 67 dart 2 door hardtop
BTW, I'm pretty sure that I bought my green's from Dr. Diff, so they wouldn't be first gen one's. b

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PostPosted: Thu Feb 15, 2018 1:33 pm 
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Bearing noises can get better or go away when you hit the brakes.

Lou

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PostPosted: Thu Feb 15, 2018 3:32 pm 
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Turbo EFI
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Joined: Wed Nov 23, 2011 11:07 am
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Location: SF Bay Area
Car Model: 67 dart 2 door hardtop
Thanks Lou, I'll check this weekend and report what I see, or don't see. b

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PostPosted: Mon Feb 19, 2018 3:41 pm 
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Turbo EFI
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Joined: Wed Nov 23, 2011 11:07 am
Posts: 2125
Location: SF Bay Area
Car Model: 67 dart 2 door hardtop
Issue solved. I'm not sure what the shop guy was looking at, but when I pulled the drum it was clear that there was some scraping inside the drum, see main one here: https://www.flickr.com/photos/151192512 ... 858614854/ and small one here: https://www.flickr.com/photos/151192512 ... 858614854/

BTW, I painted my drums with rustoleum flat rust inhibitor, it works well, doesn't burn off. That's how these scrapes were easy to see.

Here were the culprits (well actually it was the cheap chinese drum most likely). Main point of contact was one shoe: https://www.flickr.com/photos/151192512 ... 858614854/

The other slight scrape was a tiny lip on the backing plate, see: https://www.flickr.com/photos/151192512 ... 858614854/

I took the rotary sander to them a bit and noise is gone.

Lou, no sign that the axle retainer is warped or bent, see: https://www.flickr.com/photos/151192512 ... 858614854/

I could find no play at all in the wheel bearing/axle when I tried to yank it from side to side, up and down.

Brian

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