I am having brake issues with a 58 Ford Sedan Delivery. I will try to make this short but want to explain all parts involved so maybe someone can shed some light. I built the car in 1999. 68 LTD front spindles and disc brakes, single 2 3/4" piston. Rear brakes are stock drums with 15/16" cylinders. At that time I had installed a single power booster, master cylinder and proportioning valve from a 81 Ford Fairmont. It stopped fine but the pedal went almost to the floor. Nobody at that time had a clue including me but I'm sure now that it was pedal ratio. I have a 6:1 ratio. I tried a bigger 1" bore MC to get more pedal but that didn't help. I eventually removed the booster and then I had plenty of pedal but it pushed quite hard and never stopped that good. Last year I installed a 7/8" MC to soften up the pedal some, which it did. But it just is spongy and still doesn't stop for crap. I have bled them multiple different way, using different locations and orders for the bleeders. Tried it with pedal pressure holding, then opening the valve and pushing the pedal down, and gravity bled it, leaving the bleeders open for hours. It still feels like there is air in the system but I don't know how there can be, I have bled a quart or more through the system. I have sanded the pads, rotors, shoes and drums to make sure they weren't glazed. I jacked it up and had my wife step on the pedal and all 4 wheels activate right away. When I step on the pedal, I can feel the contact but can push the pedal another 2-3" after contact. I can lock the wheels up on gravel if I stand on them hard, but not on pavement. I considered installing a booster again, but have since installed a big block and there just isn't room nor do I like the cluttered look of some of those setups. The only thing I haven't changed is the proportioning valve. Are they just a distribution block or do they control the percentage and amount of fluid going out to the wheels? 58s just had the junction block and I thought about trying one of those but that would involve new lines and such. I love the 58 but the brake issue is frustrating. Thanks for any advice.
The brass block that GM and other used is basically a distribution block regardless of what they named it. A true proportioning valve has a knob on it to adjust the pressure to the rear brakes. What you are describing sounds like air trapped in the system. It can be frustrating. I recently did the brakes on my Olds and I used a different technique to bleed this time which I learned on the HAMB. After finishing my medium iced coffee and rinsing the clear plastic cup, I filled it 1/4 way with new DOT3, used a 3 inch masking tape roll as a cup holder, and inserted a clear plastic line off my vacuum bleeder. through the lid on my glass It has an end that secures to the bleeder nicely. I open the bleeder, one end of the clear tube submersed in the glass, the other on the bleeder and pump the pedal a few times. Close the bleeder and go to the next wheel starting with the furthest run and finishing on the shortest. You must keep an eye on the M/C level as a lot of brake fluid is being pumped through. I work by myself so it was hard to see the right side but on the left brakes I could see the bubbles in the line and in the glass. Once the bubbles are gone, brakes are bled, they can't suck air back in because the line is submersed in brake fluid. Once around the car and I was done with a nice firm pedal. It wasted a bit of fluid, the glass was 3/4 full when done but I needed to flush the lines after a M/C went bad so it was ideal. You might give this a try. The only thing you will lose is some brake fluid and $7.00 on the iced latte.
I bled them with a clear line into a clear plastic pop bottle so I could watch for air. But I didn't have the line submerged though. I would close the bleeder before letting up on the pedal but I will give your plan a try. Thanks!
Using a factory, or generic aftermarket, combination valve from any vehicle is more trouble than it is worth. With the Fox Chassis combo valve, its another special kind of pain. Ford changed the proportional value depending on powertrain, body type... which way the wind was blowing... Ford was also good enough to change thread sizes along with them. You'll note on the end of your Fairmont combo valve the large plug had a vent on it. That is where the prop valve lives. It may not leak fluid, but if the prop valve seals fail it can start sucking air. The end plug is not any known thread sae, metric or otherwise. Luckily a solid plug/gasket is available, https://www.maximummotorsports.com/Brake-Proportioning-Valve-Plug-1979-2004-P1411.aspx There are other plugs out there but most dont have the correct gasket/o-ring to seal. Remove the vented plug, gut the combo of the pv, install solid plug, and install a proper adjustable pv on the rear line. Or just ditch the combo valve and just install an adjustable pv on the rear line. *Some guys try to tap/plug the vented portion, and others have welded them up with some success. But the gasket/o-ring is the bigger problem with not resealing. Its a 20-48 year old gasket and not readily available.*
Yeah, if the line isn't submerged it picks up air and puts it back into the system. Submerged, it can only suck in brake fluid. It works. Even my vacuum bleeder isn't this easy or effective. Make sure you report back if it works.
@highpockets Your pedal should be high [you might be getting pad knock off or the rear shoes need adjusting] Re-install the 1" bore master cylinder . Then use a PBR VH 40 inline [remote] booster on the front circuit.
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