Springer brakes

[jorrow]

When braking with my 1938 springer, I have almost no braking whatsoever. New linings did nothing to help nor did blasting the inside of the shell. On my 47 springer the brakes are actually quite substantial. Is the difference the steel versus cast iron shell, or is it a lining issue? Any help appreciated.

[1950Panhead]

Remove 47 backing plate and shoes, install on 38, report what happens.

[len dowe]

I would say lining issue and arc if you have all the right components. Probly not making complete contact.

[exeric]

Arcing the shoes helped my '40 Chief, and '48FL quite a bit. I don't know about lining material, but I suspect there is a lot to brake material, and it's application on steel, or cast iron drums.

[jorrow]

Thanks all, you have given me some ideas, will disassemble and see what degree of contact is taking place, and what needs to be done.

[gharper]

After years of trying different things, I've discovered a system that will work and allow any brake to work at it's best. This is true of any brakes and is an essential process on our old bikes, as the brakes are sometimes not that good to begin with. The secret is the correct lining material and complete, simultaneous contact of both shoes on a clean, even drum surface.

1. Linings: Get rid of the original linings!!!!!! They are VERY hard and after use build up a glaze that makes them quite slick. Have the shoes relined with a modern, softer lining material. I don't know the name of the material, but I've seen it in a green or grey color. This can be done by a good brake shop, not Autozone!!! Bonding or correct riveting is fine. Have thicker linings put on. As I recall for my knucklehead, the original linings are 3/16", I went with 1/4" thick linings. Also be sure that the flats on the shoe where the cam operates are not worn. Weld them up and resurface them, or get new shoes.

2. The drum: Cast iron is the best, steel will work but not as good. If it is in reasonable shape, reuse it. Clean it up, carefully center and turn it on a lathe until the entire brake surface is even.

3. Assemble the shoes on the backing plate and mark them so if disassembled, they go back in the same location. On the Harley, the top pivot pin is adjustable, so set it in the center of the range and torque it down. Insert a shim of about .020" between each flat on the shoe and the operating cam.

4. Put the backing plate assembly, with shoes, cam, shims and springs in a lathe and center it. This is important, and may require making a mandrel to hold the backing plate centered, exactly as it will be on the bike. Turn it at moderately slow speed, not enough to overcome the strength of the springs
but enough to give a good finish. Trim the new linings to the same O.D as the I.D of the drum. Use a dust mask and a vacuum while doing this, the dust from the new linings isn't asbestos, but it's not friendly stuff!

Once the diameters match, remove the shims from both sides of the cam. This will allow the shoes to collapse slightly and fit in the drum. They may drag very slightly at the pivot pin, but just barely and not for long at all! Assemble and adjust the brake as normal. Pay particular attention to the wheel seals and be sure they are working properly to keep grease off the linings. This method does take some time, but what difference it makes! If fitted properly, just a slight pull on the cable will move the shoes to the spot where they make full contact with the drum, all at once! When this happens, the cam will have barely turned, which is the spot where it has the most mechanical advantage. You will be amazed at what a difference it makes!

The poor mans method if you don't have a lathe is to tape a piece of emery cloth inside the drum and turn the wheel by hand to shape the shoes to the drum. This doesn't work as well but can be a temporary fix.

gene

[Steve Little]

Nice, concise directions Gene. I printed it out and will try it on the next bike.

[Peter Cooke]

Nice, concise directions Gene. I printed it out and will try it on the next bike.

+1 to that. Very handy piece of information.

[exeric]

Thanks, Gene; good instructions.

[Rubone]

A slight bevel on the leading edge of the shoe makes for smooth engagement as well.

[koanes]

I have used Gene's method with good results. You may be surprised to see how much lining material is removed from the high spots. If you don't have a lathe you can use a drill press. You need to fix the backing plate to the table on center with the spindle and the center hole, but it needs to be able to maintain the center while being loose enough to rotate by hand. Put a coarse sanding drum in the chuck, and move the table to the side until you are just touching the high spots with the drum as you rotate the brake plate. You will need a particle mask as Gene recommends. Credit to Bob A. of the Omaha Chapter for this method.

[harleytoprock]

Cutting cast iron drums is not a problem. But what about steel drums? Do they have to be ground or can they be cut on a lathe?

[Robert Luland]

I cut both on a lathe with no problem. It's a lot easier to do with a arbor that bolts to the drum that allows a tail stock live center to be used. Note here. Use the same practices the auto guys do. Wrap that cast iron drum with an inner tube, tightly. Keeps the noise down and keeps you from eating a chunk. Bob L

[Steve Little]

A slight bevel on the leading edge of the shoe makes for smooth engagement as well.

Added hand written notation to printout

[Greg Fittro]

This post addresses same problem with my '34 VL. Informative read. Thanks to jorrow writing post and gene's technique. Had some linings made to fit my brake drum. They fit well and look forward to using them.

The problem I encountered was when I tried fitting shoes & linings on spare drum that measure 6.740" ID. So linings are too thick so I'll use gene'method. My real reason for responding was if any one can provide some measurements of the brakes and drum?

Drum ID, OD of linings mounted to shoes when mounted on backing plate, lining thickness, and OD of bare shoes mounted on backing plate. I know it's a lot to ask but would really help me with sizing correct thickness of linings in '30s.

From small amount of research the linings for a VL are in the .140" thickness. This is pretty thin .
Any help apprecited.