After having just rebuilt my brake master for the second time I disovered it leaking into the engine bay seemingly coming from the lower mounting bolt. To the inside of the car at the fire wall same situation. Tired of rebuilding has anyone had experience with SS's replacement unit? The entire brake system has been rebuilt with all new rubber so I'm running and as suggested by rootes depot valvoline synthetic dot 3-4, I'm hoping this is not my issue to much work to have it destroyed by the wrong brake fluid. If you are running SS's brake master is it working well and is it compatible with synthetic brake fluid, Rick couldn't answer for certain on this. If it's compatible my move is to replace the 47 year old unit with a new one. Any ideas, answers, or suggestions appreciated..Thanks!
Brake Fluids and Hydraulics
- Thread starter 67tiger
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The old Castrol LMA DOT 4 brake fluid is also synthetic, so I don't think that would cause your symptoms. Granted, it is a low-moisture formula- I don't know about Valvoline being low-moisture. I think you might be confusing synthetic with silicone. Silicone brake fluid might cause problems if it was mixed with synthetic or the system not properly flushed before switching. I've rebuilt my stock booster 3 times in 25 years- the rest of the hydraulics at varying intervals...I'm sticking with Castrol until I can't find it any longer.
The old Castrol LMA DOT 4 brake fluid is also synthetic, so I don't think that would cause your symptoms. Granted, it is a low-moisture formula- I don't know about Valvoline being low-moisture. I think you might be confusing synthetic with silicone. Silicone brake fluid might cause problems if it was mixed with synthetic or the system not properly flushed before switching. I've rebuilt my stock booster 3 times in 25 years- the rest of the hydraulics at varying intervals...I'm sticking with Castrol until I can't find it any longer.
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Ditto What he said Ditto . . . . . .Plus; any number of servos and masters we've redone have arrived with seals like soft tar from errant mixtures of fluids. I'm no chemist, but can tell you that certain fluids can create a seal damaging mixture. I'm a believer in keeping things stock and would opt to reline the leaking master with a brass sleeve (not stainless).
Ditto What he said Ditto . . . . . .Plus; any number of servos and masters we've redone have arrived with seals like soft tar from errant mixtures of fluids. I'm no chemist, but can tell you that certain fluids can create a seal damaging mixture. I'm a believer in keeping things stock and would opt to reline the leaking master with a brass sleeve (not stainless).
I don't have the master off yet just doing some preliminary BS with like flushing out the fluid from the unit. In the process of removing the plunger from the brake pedal I see there is a very interesting collection of gray mucus at the base of the rubber cup/seal. This leads me to believe we have a complete degradation of the internal seals caused from them not being compatible with the valvoline syn dot 3-4 brake fluid that now is throughout my complete system. Disappointing that the rebuild kits do not hold up to the more advanced brake fluids especially when told they will. I may find something different going on here but every component of the brake system is new or rebuilt, lines were flushed several times with brake cleaner, so the only fluid they've see is the Syn dot 3-4. I suppose there could have been some residue of the old castrol vegetable base remaining in the lines but I can't imagine it working its way back through the system and mixing with the new to raise havoc with the master. Clutch Master is starting to show some of the same problems as the brake just not as severe, and this system was new right down to the plumbing between the master and slave...What a beating!