Bad brakes

Hey everyone this is my first post. I recently bought a 1986 that’s been having some brake issues. It’s been pressing down to the floor and taking a good amount of pressure to stop. I’ve replaced the master cylinder twice, bled the lines more times than I can count, flushed the brake lines to make sure there’s no blockage, there’s no leaks, and the brakes are adjusted how they should be. Can anyone send some ideas my way?

 

Did you bleed the proportioning valve? Might need to adjust the LSPV that sits on the rear axle.

 

I believe I don’t have an LSPV anymore. I think one of the previous owners removed it when putting on bigger tires

 

Wheel cylinders and brake calipers? Might as well finish the job?

 

They’re not that expensive?

 

Or break lines? They can swell and collapse on the inside?

 

Yeah. Any rubber line over 25 years old can give this exact symptom.

 

How did you end up fixing? Had similar issue…ended up replacing MC, booster, rubber brake lines, brake flush…brakes like new again. Just curious what you ended up having to do.

 

I’d definitely replace the rubber lines, 2 x front and 1 rear. Push on the pedal, line swells and fails to transmit pressure. Hard to see, easy to replace…and CHEAP! Like $7 each from rockauto. Also, you said you bled everything, but everything BEGINS with the master cylinder. If you didn’t bench bleed it, you need to do that. You can do it on the truck with a buddy.