Claudiu
.020 Over
- Joined
- May 28, 2022
- Messages
- 15
- Ride
- Rocket 3 GT
Thank you for all the details. I am not familiar with DOT but I was involved with TS16949 and VDA 6. I expect process capability to be maintained that means testing a product at least every batch and have a sampling procedure in place for testing inside the batch. This is common practice for car industry but I don’t know if Triump does have such requirements since they don’t seem affiliate to car manufacturers standards and there is not enough information abou what tests they conduct if any on top of vehicle homologation process. I have bled the brakes about twelve times and I experimented with Motul RBF 600 and Motorex racing fluid to validate or invalidate different hypotheses without relevant results. The brakes were even bled by the dealer using their computer and lasted only few weeks before failing. I estimate the volume of air purged so far exceeds the internal volume of rear hose. After a couple of weeks the lever fades and to prime the brake I press the lever few times and a clear noise of fluid move can be heard from under the tank. I found evidence of leaks of some fluid on the engine cover but I don’t have means to test what that is. Maybe just condensation dripping. I am using a Stahlbus banjo with an integrated valve and I have installed a large open bubble foam on the bottom of the reservoir attempting to contain an eventual free surface effect (Rocket is one of the few bikes with integrated reservoir, almost everything else has a jar located to a certain distance from the pump). No impact at all. I am ready to service the pump and hone the cylinder but before that I will dismantle the rear hose and attempt to do a leak test under pressure with soap and compressed air. It’s interesting that only rear circuit is impacted. A significant number of bikes is impacted which excludes a random issue. Triumph had instructed the dealers to just bleed the brakes, then some to replace the ABS modulator, now the last thing is replacing the hose. It seems they guesstimate like me. I am looking forward to any idea which can help identifying the problem or conducting any experiment I didn’t think of already because this is very annoying and the manufacturer seems to be unable to deliver a solution. I forgot to mention that I used large amounts of fluid during bleeding and the level drops within two-three weeks.Thanks for contributing to the conversation. Your bike sounds normal. As the pads and rotors wear the system consumes some brake fluid. If you are still having to purge regularly it sounds like you aren't getting it all out to me. Good enough for a while until the compression ratio of gas to liquid takes more than the master cylinder can compensate, pump it again. Bleed it again. Harder, longer....
Sounds like you have Speed Nipples installed with the springs to prevent air during bleeding. They still have to be torqued on the metal to metal bevel that seals off. The springs are just used during bleeding. Tighten them back up.
An interesting read on brake lines for us in the US.
Brake hoses are the most government-regulated components on a vehicle. Anyone making brake assemblies must be registered with the Department of Transportation (DOT). All aftermarket hose, fittings and complete hoses must conform to FMVSS 106 and SAE J1401. These tests are demanding and often exceed what a vehicle will see in the real world.Brake & Front End Magazine: Auto Brake Repair Shop, Cars, Trucks
Brake & Front End serves repair shops conducting a high volume of undercar repairs by providing application-specific technical information and solutions to address emerging trends in the undercar repair segment.www.brakeandfrontend.com
The DOT standard in a nutshell says brake hoses must be flexible in a wide range of temperatures while having a predictable expansion rate so the pedal feel and ABS response is the same in winter and summer. It also specifies that hoses must be able to bend and twist at certain angles without collapsing, kinking or bursting.
FMVSS 106 and SAE J1401 do not specify construction or materials. These documents outline a test procedure that completed hose must pass.
These tests and standards include:
• Markings: Each hydraulic brake hose, except the original hoses, have at least two clearly identifiable stripes of at least 1/16th of an inch in width, placed on opposite sides of the brake hose parallel to its longitudinal axis. These are called “torque stripes.” One stripe may be interrupted by the information printed on the hose. These are to prevent twisting during assembly and installation.
• Burst Pressures: The hydraulic brake hose assembly must withstand water pressure of 4,000 psi for two minutes without rupture. Hose that is 1/8 inch, 3 mm, or smaller in diameter must be tested at 7,000 psi.
• Whip Testing: Brake hoses are continuously bent on a flexing machine for 35 hours at pressure.
• Tensile Strength: A hydraulic brake hose assembly must withstand a pull of 325 pounds without separation of the hose from its end fittings during a slow pull test, and shall withstand a pull of 370 pounds without separation of the hose from its end fittings during a fast pull test.
• Cold Resistance: A brake hose is chilled to a temperature below minus 49º F for 70 hours shall not show cracks visible without magnification when bent around a cylinder.
• Chemical Resistance: In order to test the hose’s chemical resistance to brake fluid, the hose is subjected to a temperature of 248 degrees Fahrenheit for 70 hours while filled with SAE “Compatibility Fluid.” After this the hose is subjected to a 4,000 psi burst test.
• Ozone Resistance: A brake hose assembly is exposed to ozone for 70 hours at 104° F. Any cracks seen at a specific magnification is ground for failure.
• Fitting Corrosion Resistance: After 24 hours of exposure to salt spray, a hydraulic brake hose end fitting must show no base metal corrosion on the end fitting surface except where crimping or the application of labeling information has caused displacement of the protective coating. What FMVSS 106 does not test for is damage that can take place over a longer period than 35 or 70 hours. It also does not take into account “acts of God” like impacts with road debris and installation errors.
There is not a recommended replacement interval for brake hoses. Brake hose conditions differ from vehicle, drivers and the environment. Inspection is the only way to spot a problem before a brake failure.
Brake hoses should be inspected visually and with your hands. It might be helpful to have someone pump the brake pedal to spot a defective brake hose. Failure typically occurs at the ends of the hose. This is where a hose flexes due to suspension/steering movement. It is also exposed to damage from debris and heat from the brakes.
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