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I’m new to corvettes. Have a 77. Replaced brake lines and having trouble getting fluid back through the lines. Do I have to reset the proportioning valve I order to get fluid through? Can I manually reset this or do I need to buy a new one? Any help thanks!
The shuttle valve is likely off-center, if the vehicle had a brake fluid leak in the system. If the distribution block is removed from the vehicle, remove the electrical switch and use a 'probe' to re-center the valve (Plan A). If it is still installed in the vehicle, bleed the calipers that are working, then STOMP (quick & hard) on the brake pedal 2-3 times. Often, that will re-center the valve and you can then bleed the other calipers. If that doesn't reset the valve, you will have do execute Plan A.
P.S. When bleeding brakes, depress the brake pedal slowly, so that the difference in line pressures WON'T move that shuttle valve off-center.
Last edited by 7T1vette; Apr 10, 2020 at 08:57 AM.
I’m new to corvettes. Have a 77. Replaced brake lines and having trouble getting fluid back through the lines. Do I have to reset the proportioning valve I order to get fluid through?
Just went through this with my 78 and I used the technique that 7T advises and used Heads Up page as well. Mashing brake worked for me so I didn't have to get that tool. Seems my proportional valve did not have that center valve but I would have to look. But Heads Up offers some excellent help with bleeding M/C and related topics.
Last edited by hunt4cleanair; Apr 11, 2020 at 04:10 AM.
H-m-m-m-m-. No. I knew they changed the design of the warning switch over the yrs and that if you bought the wrong one, the wire to the switch needed altering. I think that was a depth of switch issue, maybe. I did not realize that they changed diameter of the switch. Only saw 1/2" -20tpi.
Last edited by HeadsU.P.; Apr 12, 2020 at 02:31 PM.
Combination / Proportioning Valve / Brakes
