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PROGRESS REPORTS III
Disk Brake
This is no doubt my most grevious infraction of my "keep it stock looking" philosophy. It's not a decision that I came to without a lot of agonizing. In the end, though, safety trumps looks.
I know there are folks who have tweaked their front drum brake so that they claim they are able to squawk the front tire. I'm not disputing their claims - I'm just saying that I can't replicate their claims. There is just so much flex and stretch in the front brake cable/mechanism that the best it will do in my case is to just barely slow the bike down.
The rear drum brake, on the other hand, is a different story. (Remember, 57 was the last year for the mechanical rear drum brake.) I have no problem at all locking up the rear brake if I have to so there is no point in going to the effort and expense of converting the rear to either hydraulic drum or disk brake.
I had decided already this past summer to take this on as a winter project, so I began doing the research and accumulating all the bits and pieces that I would need for the conversion. Most of the stuff I got off eBay and I got some really good deals (IMO) on some of these things.
In keeping with my general philosophy of not making structural modifications to stock components, the front disk conversion can be easily reversed if desired. Also, since I had expended a lot of time, effort and expense last summer on converting my star hubs to timken bearings I wanted to keep the hubs which means a custom adapter will be required to mate the rotor to the hub.
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Master Cylinder
Master cylinder mounted in position on hanglebars.
Final Assy
Final Assy. - Yeah, I know, it doesn't really look very vintage. But, it is very comforting to know that I can stop now with just two fingers on the front brake lever instead of grabbing a whole handful of brake and barely even slowing down.
Rotor Adapter
The custom spacer that adapts the late-model rotor to the vintage star hub. Since I am using the original lug bolts to attach the adapter to the hub I needed to get a special 3/8 - 20 tap.
Mock-up
This is a mock-up just to make sure that the spacers are the correct length and everything fits. There is a spacer behind the rotor that will be replaced with a custom adapter and there is a spacer on the axle sleeve that takes the place of the original brake shoe backing plate. The caliper is just resting on the rotor in order to make sure that there is sufficient clearance between the caliper and the spokes.
Mock-up
This shows how the smaller spacer is used to take the place of the brake shoe backing plate that would normally be attached to the fork by the axle sleeve.
Mock-up
This mockup just shows the relationship of the bracket, caliper and link.
Mock-up
It's winter here in Michigan so I dismantled the entire front end and reassembled it in my basement so I can work on it where it is nice and warm.
Spacers
In order to mock-up the disk brake I made some temporary spacers out of PVC. I wanted to use the original axle parts if possible so the smaller spacer goes on the axle sleeve and replaces the original brake shoe backing plate. The larger one is used simulating the custom adapter that I need to have machined. For now, though, I just wanted to make sure that the spacers were the right length before I actually start cutting metal.
Caliper
Yet another eBay part. This is a stock late-model (2000 and up) Harley RIGHT side caliper. The calipers on the 2000 and up FL models mounts on the aft side of the fork. I will be mounting it on the forward side of the left fork so I need a right side caliper.
Master Cylinder
Another eBay part. This is a GMA 5/8" bore master cylinder. It appears to be unused and in absolutely pristine condition. Since I will only be installing a single disk on the front a 5/8" bore is sufficient. If I were installing dual disks then I would have needed a 3/4" bore master cylinder.
Bracket
This is a bracket that I found on eBay. The seller evidently produces a short run of these parts and then sells them on eBay. It is plain unfinished 3/8" steel and looks like it was cut out with a plasma cutter. It is designed to work with a stock late-model Harley caliper and an 11.5 diameter rotor. I need to modify the hole diameter where it fits over the axel. I also plan to finish the edges a little better and polish the surface and then plate it. The link attaches the bracket to the fender mounting bolt.
Rotor
Another eBay part. This is a standard late-model Harley left rotor, part number 44156-00. It's evident from the wear marks that this rotor has seen very few miles.
This page last updated on July 31, 2007
©2003-2007 David Remelts