[Midnight Goat]

Cliff notes- Drum brakes not working, preformed brake bleed rears were acting weird. No peddle resistance when car is on.


The other day i was takin my 67 goat around the neighborhood after finally having the motor running good and everything in order. Im just cruisin around seein how she holds up when the brakes started acting up. At first it was just stopping sluggishly and the brakes seemed to go on and off. I continued on heading back towards my house since the brakes werent functioning properly. Well here i come around a bend and i go to apply the brakes and nothing. i pumped the brakes frantically and finally it kicked in but very little. Im pretty sure only the fronts were working. So today i thought lets try bleeding. The front two bled fine no bubbles just fluid. The rears on the other hand is another story. The rear drivers side flowed a ton of air bubbles and i continued to bleed when fluid stopped coming out. The master was topped off with fluid but nothing. Is this normal or what? i made sure there were no bubbles and closed the bleeder valve. Im using a bleeder pump by the way. Anyway then i got to the passenger side and a couple bubbles and a little bit of fluid and then it did the same as the other side. Now im not sure if this fixed the problem but i didnt notice any difference in travel of the peddle. (it goes all the way down to the floor with basically no resistance). The red brake light comes on when it hits the floor. Id rather get some input than test drive with no brakes ahaha. Also when the car is off and i pump the brakes it resists at about half way to the floor. My setup is drums all around with what looks like heavy dutys up front and reg in the rear. They are power brakes and thats really all the information i know. Any help would be greatly appreciated! Thanks in advance.

[Malky]

If you have the dual braking system with a line to the front brakes and a separate line to the rear brakes from the master cylinder, then there is valve assemby that the two brake lines from the m/c run into. There is a spool valve in this assembly that sees front brake pressure on one end and rear brake pressure on the other end. As long as the two pressures are the same (as they should be), the spool valve does not move. But if the front or back pressure drops (like if you had a bad leak), the spool valve is pushed to one end of the assembly and shuts of fluid to the low pressure, leaking side. This is a safety feature to ensure you still have braking with the non-leaking circuit. The other thing this spool valve does when it moves is make an electrical contact which lights the brake light to warn you you have a problem.
When you were bleeding the rear brakes, the pressure difference between the front and rear circuit got high enough to push the spool valve over and shut off the fluid to the rear. This explains why the brake fluid stopped coming out when you were bleeding and why the light is coming on. There is a tool to hold the spool piece centred but I have never had to use one. Maybe the pressure applied by the pressure bleeder is high enough to activate the spool valve. First thing to do is get that air out of the rear lines. Try bleeding by just pumping the pedal.

[Midnight Goat]

So what should i do with the spool valve? Will it reset itself? Ill try regular bleeding to see if it works.