We’ve been after this tech for months. We still don’t have all the answers, but we’re closer. Since I never build any motorcycle the same as the next one, I run into issues every time I haul brake components to Baker Precision on Signal Hill for another set of lines. It’s always a roll of the dice, finding out whether my selected lines work with the calipers or master cylinders, or if they are long enough or too long.
I took a quick trip down to the new BDL headquarters in Orange recently. Since BDL acquired GMA brakes, they have become well-versed in custom motorcycle brake technology. BDL has one of the finest 45,000 square foot manufacturing facilities in the industry, and they carve out products for several well-known industry names, such as Arlen Ness, Performance Machine and Rivera/Primo, in addition to their constantly expanding product line and Jabsco pump products.
Steve Yetzke and his team operate over 50 CNC milling machines, CNC lathes, screw machines, and gear broaching. They even have a foundry. Here are some GMA brake improvements. They have developed a Softail replacement brake system. It works twice as well as stock (four pistons instead of the stock two-piston arrangement), fits better and is easier to work on and bleed. We will bring you a tech on this brake, which is capable of fitting over 10 years of Softail Harley models.
They have angled their banjo line landing area on GMA calipers for a more secure line placement. It’s easier to reach, and they designed hydraulic brake line guides into the caliper designs to help builders align brake lines securely.
They tested all types of crush washers, aluminum, copper, and O-ring. The O-ring style is by far the best sealing washer with the least amount of torque at the fitting. There is a drawback to O-ring crush washers, though, according to Darlene Baker at Baker Precision. If you use DOT 3 or 4 brake fluid, it can corrode the O-ring material over time. “I only stock aluminum crush washers,” Darlene said.
BDL was working on all new brake bleeder technology when I visited their plant. The notion is to incorporate the bleeder into the line junction for more positive bleeding, and fewer chances of a leaking. Plus they are adding a radius to the bleeder shape for a more positive mating surface. They are also eliminating any use of metric threads in lieu of the common 3/8-24 threads, except the new bagger (GMA500DD) and Softail (GMA525M) brakes, which are 10 mm 1.0 metric thread so the stock H-D banjo bleeder combo will fit also OEM part#41783-08.
Their calipers are shipped with fittings for An-3 fittings or you can run a banjo without a concave or convex fitting. They have injected new technology into their ductile rotor material. They are double disc ground and Blanchard ground for the absolutely best surface mating with brake pads.
I left the BDL factory with a new heightened level of respect for their manufacturing capabilities. The next week, we loaded our van and Kendon trailer and peeled to the Bonneville Salt Flats. We came within a pinch of a vintage class record, and then I was on a plane to Milwaukee, then back in the van and cutting a dusty trail for Las Vegas Bikefest.
So I peeled through a month before I could return to the hydraulic brake tech file. I reached out to Goodrich regarding ordering recommendations. They didn’t have any. I even left a message with sales, they finally called but basically rely on dealers and distributors to help customers. One of their offices is only 10 miles from our headquarters. Then it dawned on me, and I called Baker Precision on Signal Hill. When I need brake lines made, I run up to Darlene’s small facility on the edge of the oil wells.
Growing up in Long Beach, my dad, a master machinist, tool designer, and whip-cracking shop manager, worked on Signal Hill for 40 years. The damn place was covered with oil derricks. Now it’s home to the best coastal views in Long Beach and I’ll bet the new homeowners bitch about the few scattered oil wells around the hill. No more tall wooden derricks, though. They’re all gone.
I dropped everything, grabbed a cup of joe and peeled to Baker Precision. It’s a small shop tucked into a strip of condo-looking industry shops on a small, tree-lined street. I’ll bet you can lease one of these, run a small shop downstairs and live upstairs. Darlene predominately services the performance car and boat markets in and around Long Beach. About a third of their business is mail order. They sell high dollar fittings, hoses, and fluids for race boats and hot rods, but of course, motorcycles fit into this mix, and I’ve been a Bonneville and bike-building customer for several years.
So I strolled into the shop carrying a note pad, a camera, and a Bonneville book. Darlene wasn’t busy and her glass counter was scattered with various fittings and connectors. We started by discussing ordering and length dimensions. “Some asked for the distance from the collar, or even just the hose distance,” Darlene said. “I prefer the distance from the center of the caliper fitting opening to the master cylinder opening, since collars and fittings vary in length.”
We discussed the line coatings from clear coat to basic stainless and black-coated lines. From time to time, I will run shrink tubing over brake lines for a classic look. “My experience with coatings hasn’t been that good,” Darlene said. “The clear coating protects the line from harming paint, but it discolors, and the black is tacky and hard to work with.” Keep in mind Darlene uses production hose companies, not high-dollar companies like Goodridge from Biker’s choice. I’ll bet their coatings are higher quality.
She started to point out various guides and clamps designed to protect lines and paint. I checked on line and J&P carries several fittings and line styles. They carry what appear to be black anodized lines and fittings.
Recently, while preparing for Bonneville, I measured the line distance, but then I hauled all the components to Baker, since my master cylinder was Japanese, and the brake caliper Performance Machine. More recently, I ran a system with an ISR handlebar master cylinder (built in Europe and distributed by LA ChopRods), and a stock caliper, which was metric. ISR components are tapped to 10 mm 1.25 threads, which is a slightly different thread pitch than the GMA brakes (1.0) mentioned above. It’s a different thread pitch and they are not interchangeable. That’s one of the benefits of using banjo fittings.
“Japanese systems use 10 mm threads,” Darlene said. “Most American systems are 3/8-24 and European systems are all over the place.” Then you have AN-3 fittings, which are flared either convex or concaved. Note what Wikipedia says about AN fittings:
The AN thread is a particular type of fitting used to connect flexible hoses and rigid metal tubing that carry fluid. It is a US military-derived specification that dates back to World War II and stems from a joint standard agreed upon by the Aeronautical and Navy, hence AN.
AN sizes range from -2 (dash two) to -32 in irregular steps, with each step equating to the OD (outside diameter) of the tubing in 1/16-inch increments. Therefore, a -8 AN size would be equal to ½-inch OD tube (8 x 1/16 = 1/2). However, this system does not specify the ID (inside diameter) of the tubing because the tube wall can vary in thickness. Each AN size also uses its own standard thread size.
AN fittings are a flare fitting, using 37° flared tubing to form a metal-to-metal seal. They are similar to other 37° flared fittings, such as JIC, which is their industrial variant. The two are interchangeable in theory, though this is typically not recommended due to the exacting specifications and demands of the aerospace industry. The differences between them relate to thread class and shape (how tight a fit the threads are), and the metals used.
Holy shit! I looked at the associated chart and AN-3 fittings are SAE 3/8-24 threads, or 1/8-inch 27 pipe thread or NPT. What the hell? If you try to run a 1/8-inch pipe fitting into 3/8-24 threads, you’ll run into problems. I spoke to Lee Clemens at Departure Bike Works and he added to the mix. “If you’re in a jam with 1/8-inch pipe threads, you can tap them to 3/8-24 and use a banjo fitting, but you must have a machined surface for the crush washer to seal.” Lee also mentioned that until 2002, H-D used 12 mm threads at the top of the line, and 10 mm at the bottom. After ’02 all H-D brake lines are 10 mm. So if you are installing an aftermarket front brake master cylinder on your H-D you will need to think 3/8-24 at the top and 10 mm at the bottom.
We discussed banjo fittings and Darlene suggested them for tight spots and harsh bends. “But they can be more prone to leaking due to the multiple surfaces and size of surface,” Darlene said. She also suggested always replacing both lines if you have multiple lines in a stretch, since good tight -3 lines provide very positive braking. “It’s all about pressure, not volume.”
I asked her about 1/8-inch pipe threads. “Only a few proportioning valves come with pipe thread,” Darlene said. Most automotive applications use 7/16 threads, whereas all performance and aircraft applications use 3/8-inch threads. “Very few folks use the old brass auto junctions anymore; they usually replace them with aircraft type AN fittings. Some 99 percent of the fittings we use are convex (male) AN fittings.” The concave fittings are also referred to as inverted flair.
Okay, so here’s what we can recommend. Measure the length of the cable from the openings, center to center. Make sure you note the angle of the cable departure on both ends carefully.
“Most guys don’t think about the direction of the cable,” Lee said. “We usually lay out the cable on the counter at the shop, and then take the customer through the position of the master cylinder and the caliper to determine the angle of each fitting. We want them to go home and just bolt the line into position.” Also note any flex or slack needed for movement such as swing arms or forks. You may also need a junction to a flexible line, if motion is constant or severe. I would always suggest dragging all the components to a shop or fitting store for the most positive results.
BDL and GMA Brakes
Baker Precision
562-427-2375
Performance Machine
