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techtalk:ref:wheels03 [2020/06/12 04:17] hippysmack |
techtalk:ref:wheels03 [2020/06/24 23:27] hippysmack [DOT 5] |
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| * If silicone is introduced into an older brake system; \\ The silicone will latch onto the sludge generated by gradual component deterioration and create a gelatin like goop. \\ (which will attract more crud and eventually plug up metering orifices or cause pistons to stick) \\ If you have already changed to DOT 5, don't compound the problem and change back. \\ You will never get all of the silicone out of your system. Just change the fluid regularly. \\ For those who race using silicone fluid; \\ Crack the bleed screws before each racing session to insure that there is no water in the calipers. ((http://importnut.net/brakefluid.htm)) | * If silicone is introduced into an older brake system; \\ The silicone will latch onto the sludge generated by gradual component deterioration and create a gelatin like goop. \\ (which will attract more crud and eventually plug up metering orifices or cause pistons to stick) \\ If you have already changed to DOT 5, don't compound the problem and change back. \\ You will never get all of the silicone out of your system. Just change the fluid regularly. \\ For those who race using silicone fluid; \\ Crack the bleed screws before each racing session to insure that there is no water in the calipers. ((http://importnut.net/brakefluid.htm)) | ||
| - | ===== Replacing Brake Fluid (Dot 3 to Dot 5) ===== | + | | Note the gooey mess from mixing Dot 5 and Dot 3 fluids. ((photos by FearlessFrisbee of the XLFORUM http://xlforum.net/forums/showthread.php?t=1508535)) ((photo by brianbbs67 of the XLFORUM http://xlforum.net/forums/showthread.php?s=b7cdc14394b5d341991efe72f18f9aad&t=1932868&page=2)) ||| |
| + | |{{:techtalk:ref:wheels:dot_5_-_dot_3_mix_goop_1_by_fearlessfrisbee.jpg?direct&300|}}|{{:techtalk:ref:wheels:dot_5_-_dot_3_mix_goop_2_by_fearlessfrisbee.jpg?direct&300|}}|{{:techtalk:ref:wheels:1977_front_master_cylinder_piston_gummed_up_by_brianbbs67.jpg?direct&300|}}| | ||
| + | ===== Swapping Brake Fluid (Dot 3 to Dot 5) ===== | ||
| The following is found in HD Technical Service Bulletin M-712 dated June 16,1977. \\ | The following is found in HD Technical Service Bulletin M-712 dated June 16,1977. \\ | ||
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| * The change to Dot 5 brake fluid was made with HD production motorcycles in September of 1976 ((HD Service Letter M-28)). It is of silicone chemistry and not being water miscible, it must rely on the silicone (with some corrosion inhibitors) as a barrier film to control corrosion. Water is not absorbed by silicone as in the case of DOT 3-4-5.1 fluids, and will remain as a separate globule sinking to the lowest point in the brake system, since it is more dense. ((http://importnut.net/brakefluid.htm)) | * The change to Dot 5 brake fluid was made with HD production motorcycles in September of 1976 ((HD Service Letter M-28)). It is of silicone chemistry and not being water miscible, it must rely on the silicone (with some corrosion inhibitors) as a barrier film to control corrosion. Water is not absorbed by silicone as in the case of DOT 3-4-5.1 fluids, and will remain as a separate globule sinking to the lowest point in the brake system, since it is more dense. ((http://importnut.net/brakefluid.htm)) | ||
| * When using Dot 3 brake fluid, the brake system should be drained, flushed, and refilled with new brake fluid every year to eliminate any contamination such as sludge. This yearly service was eliminated when D.O.T.-5 silicone fluid was used instead and with improved performance. ((HD Service Bulletin #M712 dated June 16, 1977 pg 1)) | * When using Dot 3 brake fluid, the brake system should be drained, flushed, and refilled with new brake fluid every year to eliminate any contamination such as sludge. This yearly service was eliminated when D.O.T.-5 silicone fluid was used instead and with improved performance. ((HD Service Bulletin #M712 dated June 16, 1977 pg 1)) | ||
| - | * HD changed to DOT 5 brake fluid in production models in September of 1976. \\ Silicone brake fluid reduces corrosion, will not degrade the "rubber" components, and sludge will not form in the system. It will not absorb water, does not attack painted parts, and has a higher boiling point than conventional brake fluid. When stored under normal conditions it has unlimited shelf life. However, it is somewhat harder to bleed brakes with Dot 5 because of its viscosity. ((HD Service Bulletin #M712 dated June 16, 1977 pg 1)) | + | * Silicone brake fluid reduces corrosion, will not degrade the "rubber" components, and sludge will not form in the system. It will not absorb water, does not attack painted parts, and has a higher boiling point than conventional brake fluid. When stored under normal conditions it has unlimited shelf life. However, it is somewhat harder to bleed brakes with Dot 5 because of its viscosity. ((HD Service Bulletin #M712 dated June 16, 1977 pg 1)) |
| * Dot 5 in its pure state offers a higher boiling point (500F) however if water got into the system, and a big globule found its way into a caliper, the water would start to boil at 212F causing a vapor lock condition (possible brake failure). DOT 3 fluid with 3% water content would still exhibit a boiling point of 300F. Silicone fluids also exhibit a 3 times greater propensity to dissolve air and other gasses which can lead to a "spongy pedal" and reduced braking at high altitudes. ((http://importnut.net/brakefluid.htm)) | * Dot 5 in its pure state offers a higher boiling point (500F) however if water got into the system, and a big globule found its way into a caliper, the water would start to boil at 212F causing a vapor lock condition (possible brake failure). DOT 3 fluid with 3% water content would still exhibit a boiling point of 300F. Silicone fluids also exhibit a 3 times greater propensity to dissolve air and other gasses which can lead to a "spongy pedal" and reduced braking at high altitudes. ((http://importnut.net/brakefluid.htm)) | ||
