Something is draging on inside of rear brake drum, what is it

[bmklawt]

1927 Touring with wire wheels.
This is driving me nuts and I cant figure it out, so I built a rear axle from parts and when I put on my right rear hub without the brake band on I can here something dragging on the brake drum, it least it sounds like it's dragging on the drum, I can't figure what the hell it is.
Without the hubs on I and rotate the axles and I don't here it, with the hub on I hear it, I put a feeler gauge between the brake drum and backing plate all the way around and there is no interference, I put some putty on the dust cap that holds the felt washer to the end of the axle tube and put on the hub, when I take the hub off and the putty shows I have 1/16" to 1/8" clearance, drum is not touching the brake cam.
What is making this noise that sounds like something is dragging on the brake drum, not a metallic sound more like the drum is dragging on a thick piece of paper, doesn't happen on the left side, I've tried both drums, same result.
Any ideas?

[Scott_Conger]

I don't know what's dragging, but I do know what's missing: if you have a gap between the inside of the hub and the dustcap, it is because you are missing the felt seal which seats on the hub and presses against the outside of the dust cap (what is pictured in this link is a standard wood spoke hub, but your hub has the same recess): http://www.mtfca.com/discus/messages/82 ... 1541005897

[DanTreace]

May be the thrust washer on that side, if the 'drag' is only brief and not a full rotational drag.

A bronze thrust washer which isn't fitted perfectly flat when it was thinned down on fitting the axle gears, can cause a partial drag like sound.

Seems like you checked anything the drum could rub, like the spring perch nut and cotter, the radius rod bolt heads, and the brake cam.

[Allan]

When I was working on Henrietta to waken her from her 61 year slumber, I pulled both rear wheels to check the wheel bearings. I found the cast iron brake shoes buried in accumulated grease and road grime, which i had to chisel out. She got a set of new lined brake shoes and now has the best hand brake of any of my T's. However, she developed a persistent, but somewhat intermittent scraping noise on the right side. I pulled the wheel again and checked everything. The brake shoe spring was polished, but that happened when all the crud was in there before I cleaned it out. I put the wheel back on, with a shim, and the noise was still there. It went away sometimes when going around a corner. I had a fellow from New Zealand riding with me on a National rally, but he could not hear the grinding from the left side of the car. I was completely baffled.

Then I had a promotion to do for Haigh's Chocolates in my 1912 van for Easter. Would you believe that exact same grinding/scraping noise was now evident in the van. It went away when I put my new-to-me right hearing aid in my pocket!

Allan from down under.

[Norman Kling]

If the thrust washers inside the differential are worn, you would be able to move the hub in and out. It would, however be worse on the left side because the ring gear would hit the pinion gear and stop the movement toward the right. Since it would move toward the left, it could be pulling the right hub closer to the backing plate. If there is no end play in the axle shaft, it is not likely that the thrust washers are the cause. These are the things which are most likely to cause the problem.
1. worn taper on the end of the driveshaft or inside the hub.
2. If you have the wood spoke wheels, it could be the length of the bolts holding the spokes to the hub. The nuts should be thinner than the usual nuts for carriage bolts. About 3/8" The threads are then peened to keep nuts from loosening. Look carefully to see if they are scraping on anything.
3.The nut which holds the spring shackle perch could also be scraping.
4. and one of the most common things would be the brake shoe scraping around the drum as the wheel turns.
5. Aftermarket grease seal with thicker cap which goes on end of end of housing.
A very thin layer of Prussian blue can be put on the suspected area would be wiped clean by any part coming in contact. Sometimes grinding just a little bit off can fix the problem.
Norm

[kmatt2]

On a 1926-27 T rear axel it is the backing plate clips and the brake band return spring that keeps the brake band centered. With the brake ban removed and if the brake rod is not connected then the brake cam can rotate so that the lobe end of the brake cam is hitting the brake drum. Try connecting up the brake rod and put the hand brake lever all the way released forward with out the brake band in side. Do you still hear the noise when rotating the wheel ? If yes then your brake rod lenght needs adjustment, if no then the noise was the brake cam lobe hitting the drum.

[jiminbartow]

There are 4 brake shoe clips (A in the left picture) that are riveted to the round backing plate that holds the brake shoe centered and against the backing plate. It is common for the curved portion that holds the shoe in place, to wear through until they break, leaving nothing to hold the brake shoe in place, allowing the brake shoe to drop and rub against the brake drum. That may be your problem. I have attached a photo of one of the clips. These are sold by Snyder’s, Part # T-2560-CL. Size-wise, they are only about 1” long x 1/2” wide. When I restored my rear end, all four of my clips were broken so I bought new ones and riveted each one in place with 2 pop rivets. Jim Patrick

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[bmklawt]

Well I've had the hub on and off a half dozen times to try and nail down the noise then I found this little piece of copper wire stuck in the paint hanging off the edge of the backing plate, didn't think anything of it and pulled it off but the next time I put the hub on the noise was gone. I cant believe it was this wire, I've tried to reproduce the sound with that wire but its just to damn small, all I know for sure is the sound is gone now.
Thanks all for the advice

[jiminbartow]

Congratulations.

[Norman Kling]

Good! Hope that was it.
Norm