Many bike shops will have tackle boxes full of specific parts for hydraulic brake systems. Fluid compatibility guide a detailed list of fluidschemicals with their compatibility ratings for use with the most common o ring materials.
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O ring for brake fluid. Virtually any size o ring is available off the shelf in nitrile butalene or neoprene but ep needed for resistance to brake fluid is impossible to find. Nitrile o rings are not advisable for use with automotive brake fluid ketones phosphate ester hydraulic fluids and nitro and halogenated hydrocarbons. I have a whole bag of epdm o rings that are the correct size for the cleveland 300 series brake calipers as used in most ga cleveland brakes with 5606 type mineral based fluid and as used by stemme gmbh wdot fluids. I discovered that bearing houses and seal companies do not carry o rings made of ep. Viton is not recommended. Nitrile o rings which have a temperature range between 54 and 149 degrees celsius are suitable for use with water petroleum oils and some hydraulic fluids.
Id recommend looking for a replacement from the manufacturer or a good bike shop. Of these three rubber types epdm is the only choice for seals in braking systems using a glycol based or silicone based dot approved or pure racing brake fluid. O ring chemical compatibility chart learn how different o ring materials and chemicals interact. Looking to source the small o rings that seal the e brake actuating plunger within the rear calipers. Please confirm which o ring material is friendly to brake fluid. O ring groove design guides o ring groove dimension guidelines for standard o ring grooves metric o ring grooves jis o ring grooves and other o ring gland designs.
Its small about 580 outside diameter with 060 section. Look at the following compatibility list dot 3 is under brake fluid dot 3 glycol type. On a recent tour on an old and rare bike i had a problem with the seal on the hydraulic clutch. O ring materials compatible with brake fluid select a material to show its compatible chemicals aflas 4 buna n nitrile 1 butyl 4 chemraz 0 epichlorohydrin 1 ethylene propylene 4 fluorocarbon 1 fluorosilicone 1 hypalon 0 kalrez 0 natural rubber 1 neoprene 1 nitrile hydrogenated 3 polyacrylate 1 polysulfide 3 polyurethane cast 1. If you buy your brake fluid from pegasus auto racing supplies use epdm seals in that system. Other materials used for o rings include ptfe universally noted for its chemical resistance but difficult to install due to minimal elasticity.
Basic o ring chemical resistance compatibility information is based on isolated generic o ring material testing in optimal conditions at room temperature and pressure. Fep encapsulated fep is similar to ptfe and is used to cover viton or silicone o rings to offer the chemical inertness of ptfe with some elasticity. Standard o rings will degrade very quickly in dot fluid as it is highly corrosive.
Gallery of O Ring For Brake Fluid
