Brake Drum Pitting (53 K)

[Mayday53]

Rear Hub

Rear Hub (6).JPG (140.97 KiB) Viewed 17150 times

I am restoring my 53 K model. The brake drums are a bit pitted and some of the old brake material fused to it. We were able to smooth grind the brake material off, but there is quite a bit of pitting on the drum surface; nothing real deep, but clearly there. Two questions:

1. How far can the inside drum be milled and remain in specs for proper braking?
2. Can the drum braking surface be plated so that the surface has the necessary specs for brake operation?

[sportsterpaul]

Dude, buy a used drum on eBay. There may even be some NOS (new old stock) drums out there, but I assume at an astronomical price. I sold a pristine one last year to finance my move to Florida. These are your front brakes man, they suck enough by design, so being poor to begin with and adding worn out is no way to go.

There is no practical way to plate enough material onto the drum, and plated surfaces would not be appropriate for any braking friction surface. I guess you might flame sputter the same steel onto the drum, I am pretty sure it is not cast iron. I suspect this would cost well over ten times cost of a decent used drum, if it can be done at all. Dude. These are your front brakes. Buy a used drum on eBay.

I looked in my 1971 service manual and found no data on max drum inner diameter. There was also nothing about machining it. So if you want to risk your life, and that is exactly what you are doing, just machine the drum surface as lightly as you can and still have a nice continuous finish. I suspect the rusted sides of the drum might be OK, but that is the worse rusting I have ever seen. Your call, not ours.

Once you have machined it out, you are now a self-appointed brake engineer. Assemble the whole mess, and pay close attention to how far the cam goes before you get braking action. To do this right, you will need to remove the pads from the shoes, since that is "worse case." You might also want to cut giant holes in the drum or backing plate so you can observe the travel, This of course ruins those parts. If you feel you have not run out of cam action when the bare shoes hit the drum, under full lever pressure, then you are welcome to rivet on some shoes and put everything back together.

Or you could just buy a used drum on eBay.

[hayleyl]

I agree - that drum needs to be turned into a flower pot. It is not worth the time energy or effort to repair. Source a replacement. Remember - brakes are your friend and in the case of K's and Panheads we start from a pretty low base. Cheers Hayley.

[Hammie13]

I have a very nice original paint drum/hub I'll sell you for $150 shipped. If you want a pic of it,call me at 615-756-9586 and I'll snap one and send it. Mike

[thefrenchowl]

Talking about H-D drums and from 30 years + of riding them, the front 1/2 width old K drum is about 10 times better than the later full width drum...

Patrick

[Mayday53]

Thanks fellas. Sportsterpaul...I appreciate the candid feedback, it is what I expected but thought it was worth the question in the event there was a reliable alternative.

[sportsterpaul]

You're welcome Mayday53, and I hope I didn't come off as snippity-- sometimes jaunty can sound like jerk if its by written communication. I have become much more careful in my old age, though I certainly am no one to tell other people-- I have run tires down to the red cord-- but at least it was a rear. I guess that is the other factor, I am no longer a worker in boom-and-bust Silicon Valley, where money was often tight. Now, for 50 or 150 bucks, I would just spend the money. And I suspect there are people that would buy your rusty brake drum for a few bucks.

Pastrick, I am delighted to hear the "half-drum" early brakes works better than the 1964 full-width drum. I have that full-width drum on my 1962, and one project I have is to get the right front-end on it, which is the half-drum. It is really scary, riding that thing-- and having to depend on the rear brake so much. Also Patrick, thanks for all the info on Pohlman Studios in the other thread- that is just so fascinating to me.

[Hammie13]

I have a complete front wheel/brake, tire(original,show only,I wouldn't trust it after all these years) that I'll part with for $300 plus shipping. It's a Borrani high shoulder wheel,speed eagle tire and original paint half hub front brake. The backing plate is still nice and brake shoes are very nice condition.

[EKHKHK56]

Mayday, I have 41 years of K riding with the stock brakes. They work fine even two up and I prefer the feel over disc brakes. Unfortunately that drum is toast, saw many and have many that the rain got to. One tip, when you get your drum or brake shell as called the early is different from the late. REAR: 52-54 for small hub up to VIN# 54 1688. Uses different shell, shoes, backing plate, operating shaft, pivot and linings compared to 1954 #1688 & newer. FRONT: 52-53 uses different shoes, backing plate, shaft, pivot and linings compared to 1954 & newer. Same shell though, 52-56... I have to look at samples to see difference in shells for rear. OK so you have early brakes regardless. The shoes and linings are different. Alloy early, steel later. If you can`t find good early shoes you can put the newer linings on the old shoes as they are thicker, and fit to use. This will give you better braking without changing everything. Less free play in the system also. You won`t have to run the adjuster all the way up like some you see! Erik

[sportsterpaul]

I can see I have the 54-and-later setup, two of them. One is destined for my 1962, the other as a backup until I can see what my 1954 needs. I do remember having some alloy shoes, but I must have sold them. Here is the inside of the backing plate, casting part number is 44147-54.

Rusty-ft-wheel-plate-inner_sfw.jpg (102.31 KiB) Viewed 17033 times

Here is the outside of that plate

Rusty-ft-wheel-plate-outer_sfw.jpg (88.17 KiB) Viewed 17033 times

And here is the axle

Rusty-ft-axle_sfw.jpg (94.34 KiB) Viewed 17033 times

All this is eBay or swap meet stuff, so no guarantee it is correct. You guys amaze me with your knowledge, but like Dr Dick said, if you look at a lot of bikes, pretty soon it sinks in. You guys must have looked at thousands of bikes to get all this straight.