Why does my rear brake cylinder keep blowing and how do I fix it?

Bill:

Check your master cylinder. It could be a piece of junk lodged in the fluid port for the rear brake lines, or in the brake line its self. The fact that both rear wheels spin tells me that if it is a clogged line, it is between the two manifolds, (one next to the master cylinder, and the other where the rear brake line splits into two... one for each rear hub. Or it could be that the piston in the master cylinder needs to be replaced. I would disconnect one brake line at one rear wheel and disconnect the rear brake line at the manifold (near the master cylinder)and blow that line out with air pressure. . do not leave the rear brake line connected to the master cylinder as you blow air through the lines as you may damage the master cylinder piston packings. You'll have to bleed the brakes when you are done.

pull the rear bulbs out and try again, does it have a third brake light? does it work?

try to clean the tubing hose where the brake fluid
passes,,,try to bleed all the brake front n rear

proportioning valve on brake line looks like a square block that the brake lines go into

if the brakes over extend the cylinders will pop, make sure you have properly adjusted the brakes, also make sure the emergency brake cable is working and not stuck partway on which will hold the shoes away from the cylinder.
the shoes should be adjusted so that you spin the wheel and it turns twice and stops.

You will need a brake inspection, the rear wheel cylinder could cause this or a whole new rear brake set

Hi Chris, The brake system is basically very simple. If you have duel braking on your vehicle, the usual method is having two brakes operate on the front with for example the left rear and the other system will also operate two front and the right rear. This type of system will have two calipers on each of the front wheels. The tandem system works in a slightly different way, having the forward part of the cylinder pressurizing the rear brakes and the rear part of the cylinder pressurizing the front. I think under the circumstances you are describing, I would have a friend sit inside and pump the brakes repeatedly until the system becomes pressurized (maybe twenty thirty times of pumping the brake pedal) and then ask him or her to keep it pushed firmly down until you find out where its leaking. The amount of brake fluid you report having been sed would indecate a severe leakage. Check the lower parts of the rear wheels for signs of leaking wheel cylinders and then dito for the front wheels. Any signs of wetness at these areas and along the brake system (the plumbing or pipe work) will indicate where the leakage is. If you cannot identify a wheel which is leaking, carefully inspect around and blow the master cylinder and if this no sign go along the fluid lines, taking special note of where the damaged pipe was repaired. If there is a blockage in the line, air may be trapped at that point causing difficulty in pressurizing. Once the place of leakage has been identified it must be attended to before bleeding the system. When bleeding, begin with the wheel furthest from the master cylinder, and work your way back to the master cylinder one wheel at a time, until you reach the closest.Keep in mind that you may find it required to pump the pedal many many times before opening the bleed nipple.Regards John

Yes, a light clearer fluid would be brake fluid, rear end fluid would be like syrup. They will usually start to seep just before they blow out. A quick stop right now would probably leave you without brakes. There is no easy fix, you need to replace both rear wheel cylinders and the shoes, hopefully the drums can be turned and reused. New wheel cylinders and shoes should be less than $50 in parts if you do it yourself. Just fix it soon as this is an expensive accident waiting to happen.

what do you meaqn blowing usually the seize up over time if the part is new and guarenteed you should not have this problem and when replacing do you bleed the brakes so they have equal pressure

Check first the brake fluid level. This is found under the hood on the drivers side. Sometimes when the fluid gets low it will cause the light to blink. If the fluid is fine then have you Back brakes checked. If you have worn brakes this also can cause the light to blink or if you have drum brakes the wheel cylinder could be leaking fluid. You can look under the back of the vehicle on both sides of the insides of the rear tires and if you see alot of wet stuff on the inside of the rear wheels then you have a wheel cylinder that is leaking and could cause you to not have any rear brakes if it blows out. If you can do back brakes you can buy everything cheaper at any Advance or Autozone Store. I always buy new wheel cylinders instead of rebuilding them. Much cheaper. But do both rear wheels. Don't just do one. Hope this helps,