hey so i have a 86 chevy blazer and i have had to refill my brake fluid twice now in a span of about 3-4 months
i would like to fix this problem tomorrow since i had all day so any suggestions on where the leak would be, and wat to do to fix it?

 

You probably have bad seals in the rear brake cylinders. You will have to take off your rear tires and brake drums to see. If the fluid leak is really bad then the brake drums and backing plates will look wet constantly never dry. Also depending on how old your front disc calipers are they could leak from the piston seals. You could also have a bad master cylinder with fluid leaking into the vacuum booster which would mean that the plunger seal is needing to be replaced meaning, NEW MASTER CYLINDER.....

With a truck this old they could all be leaking a little which is adding up to lots of fluid loss so check out the obvious first by checking the calipers and the rear drums...might while your under the truck check the brake lines for any damage, check junction blocks on the rear axle for leaks, check the lines where they go into the rear backing plates (actually the wheel cylinders) for leaks.

Just got to look at these places first, since they are the easiest to see with out pulling things down to non driving status.

If those areas are fine then you will have to try to remove the master cylinder from the vacuum booster to see if the leak is in the plunger rod, then you will have to remove the master cylinder from the vacuum booster.

To Remove it check under the dash by the brake pedal there should be a connection either a bolt or a pin of some sort this will have to be taken out and possibly the brake light switch (not sure on this old of one). Then you can remove the bolts holding the master cylinder to the vacuum booster and reinstall in the reverse order when you get the new/rebuilt master cylinder...

Hope this gives you some ideas to start.

Good Luck

 

I own some older Blazers myself.
First I would check the brake lines from front to back. Check for areas of rust.
Checking for a leak out of the master cylinder is actually really easy. Just take off the 2 mounting nuts and slide it forward off the booster. You don't need to loosen the brake lines at all.
A leak from the front caliper is rare, but you can check the connections at both ends of the flex hoses.
Check for leaks at the wheel cylinders on the rear. If it looks damp around the wheel cylinders, take a small screwdriver and CAREFULLY pull the rubber a little bit away from the center around the actuator pins and see if there is fluid inside. If there is, replace the cylinders.
I think that might cover it. Post back to let us know what you find.

 

alright thx for the tips!
so like i said, im going to try to tackle this tomorrow so ill tell u guys how it goes!
again ty its much apreciated!