Rear drum brakes not releasing.........update 12-8-07

[BigBlackDodge]

I had to crack open the bleeder to get the shoes to close-in. Any ideas? Master cylinder? Porportion valve?


BBD

[73chgrSE]

wheel cylinders?

[resq302]

I had the same problem on my 69.  Turns out the hold off (metering valve) that is in the middle of the distribution block to the rear brakes seemed to be acting like a one way valve allowing fluid through but not returning.  This was a brand new repro unit that I got from In Line Tube.  After fighting with them for a while, they made good on the part. 

Try going along the line going back to the front of the vehicle and just crack open the connections.  When you get to a connection that does not have the brake fluid spray out under pressure, you know the problem is between there and the last connection that had pressure on it.

[Plumcrazy]

Try going along the line going back to the front of the vehicle and just crack open the connections.  When you get to a connection that does not have the brake fluid spray out under pressure, you know the problem is between there and the last connection that had pressure on it.

  The rear brake hose is also a likely cause.

[Musicman]

Metering valve is not part of the rear circuit, only the front. However, there are a number of other things it could be depending on the actual syptoms... Wheel Cylinders are a likely cause... bad Proportioning valve maybe... Residual Pressure valve, doubtful... sludge in the lines, not likely if the system has been properly flushed and maintained on a regular basis, if not... sludge may be fouling the system components... Dirt, oil or grease in the drums... Hows the E-Brake system working?

[BigBlackDodge]

Bingo!

Finally found time to figure it out.

I tried pulling a vacuum from the rear wheel cylinder and from the master cylinder..........nothing, vacuum would build up and hold there. I have an extra  ruber line that connects to the rear axle so on a hunch I cut the line and the vacuum fell. The ruber line had gunked pretty good and blocked all passage of the fluid.

Now to swap out the line and bleed the brakes.


BBD

[Musicman]

If you had sludge there, then you'll want to flush the entire system now, and possibly replace the wheels cylinders as well. Once you get everything working correctly again, be sure to flush the system on a regular scheduled basis.

[BigBlackDodge]

If you had sludge there, then you'll want to flush the entire system now, and possibly replace the wheels cylinders as well. Once you get everything working correctly again, be sure to flush the system on a regular scheduled basis.

10-4

Thats exactly what I did..........even changed the shoes.

BBD