Hi all,

Need a hand with something. Just did a frame off on a 74 vette. Every brake line and hose was replaced with new. All the calipers are new "Vette Brakes Products" stainless steel. The master cylinder is also "Vette Brakes Products" stainless rebuilt. The only thing I reused was the original proportioning valve which sat around for a few years without lines attached. I have done tons of corvettes and always have great success gravity bleeding the brakes. I have never had a problem till now.

I am positve there is no air in the system and the master cylinder was also bleed properly. Can't get the pedal up. Spongy feel and the front end dips like the rear brakes are not working. I read all my vette manuals and the only thing I came up with is a note about applying very heavy pedal pressure to reset the proportining valve. I did this until I heard a pop sound like something moved or reset, but to no avail I don't have brakes worth a hoot. Also the brake waring light is not on. Should I scrap the proprotioning valve or is there another way to deal with this problem.

Thanks to you all this is a great site and Crosley my 700R4 really brought this car to life. Now if I can get her stopped I'll be happy.

Dave

If Iam out of line sorry, but did you bleed both sides of the rear cal. Only car I know of with two bleaders on each wheel. Good luck. JF

With the corrosive properties of brake fluid, and the valve sitting for that long, I would question the working order of the valve. When dealing with the brakes, I don't believe in taking chances. I would have replaced that with the rest of the system. Just my opinion!

I have a vette and have had the same problem you have experienced. I agree with the other posts. Blead the inside bleader valve first then the outer. Start with the longest brake line and work to the shortest. Replace that old valve you mentioned with a new one. The gravity method works only if your lines are completely free of matter. The sligntest bit of junk in the line will prevent that method. Go to the parts store, get a $6.95 one man brake blead kit. Place your recovery bottle HIGHER than your caliper. Keeping your master cylinder full pump the pedal up and down until you no longer get air bubbles in your recovery bottle. I have never had this method fail.

any questions call or visit muskegonbrake.com and they could help you with any tech question on the brake system towards your corvette.

Go to the dollar store and buy a spray bottle usually a $1 as the name would imply, or if your really cheap use an old windex or similar spray bottle attach a hose on the plasic tube on the end of the sprayer and the other end of the tubing to your bleeder and pull the trigger, these spray bottles have a check valve in them and as you know allows the liquid to spray out but not move backwards into the bottle or in this case your caliper/brake system, I have found that sometimes I have to remove the caliper to get the bleeder at the highest point in the system, if that doesnt work you can always cut out the floor boards and "fred Flinstone" it. Good luck......

Sounds like the pop was your corroded valve resetting itself. It might have prevented proper bleeding of the brakes, and/or might still. I agree with replacing it and rebleeding. The light probably should have been on before the 'pop', but there might be so much corrosion the circuit couldn't complete and turn it on (or there might be a problem with the light circuit).

Those calipers are known for keeping air trapped inside them. Sometimes you have to remove the caliper to bleed them (but a block of wood in the caliper to keep the pistons in). I have even heard of having to move the pistons in/out by hand to get the air out.

You might also try bleeding the rear brake line starting at each joint (starting at the master going back) till you have fluid to all lines with no air.

A new prop. valve couldn't hurt.