Hi The brakes on my 65 chevy is not working properly anymore, and I can see the brake fluid reservoir is all empty so I have to refuel the system. Which type of brake fluid shall I use? (DOT3,4,5?), and how much - also I assume it would be a good idea to drain the system before adding new fluid? - how do I do this correct? Is it normal that the system gets drained over time, or should I start looking for leaks? Looking forward to your input Thanks! Martin
I would look for leaks. Then start with bleeding the master cylinder and the RR, LR, RF and LF. Make sure the master cylinder always has fluid in it.
after checking for leaks, my guess is a wheel cylinder, if not are you running a power booster, if it is leaking vacuum it will draw brake fluid out of the master.
Use DOT 4 if you can find it . DOT 3 is pretty good , DOT 4 has a higher boiling point , important if you have disc brakes are like to drive your drum braked truck in the hills at speed (ahem) . Finding fluid leaks is opretty simple , remove the brake drums and *gently* lift the edge of the rubber dust boots on each end of each cylinder ~ any wetness means both cylinders on that axle are kaputi and need changing RIGHT NOW , prolly the shoes too as brake fluid on the shoes makes them grabby , I rolled a vintage car once due to this . If you're going to replace two cylinders , take a moment to jack up and safely block the truck , scrootch underneath it and flex all three brake hoses , if even one tiny crack , replace ! . Then find a 6 point box end wrench that fits the bleeder nipples on the other two brake cylinders and see if you can open and close them ~ do not snap them off , if they're stuck STOP , get a ball peen hammer and SMACK them dead on to shock the rust loose , try the 6 pointed box wrench again . Still no joy or one broke off ? no worries , you didn't really want to die horribly in a mangled fiery collision anyway.... Remember : never , EVER turn or machine those old brake drums ! .
