Video of spinning my front left wheel off the ground..

[BMERDOC]

Dang Dude! Are you still having this problem?

I'll re read in a little while and get back.

[BMERDOC]

Ok. Start over. You have replaced the MC several times and the calipers. There are two things that you have not changed. The prop valve and the braided lines. The one picture looks as though the braided line has/had a good crimp on it. If it had a crimped spot in it you would have some residual residual pressure on the caliper side of the crimp causing the rotor face scoring. It wouldn't be a lot of pressure but enough to hold the pads on the rotor causing the questionable speed of the free wheeling, well, wheel.

[oldblue1968chevy]

I can get new pads/rotors free I THINK (lifetime warranty) PLEASE HELP

Im getting 1 master cylinder in the AM and 1 caliper via orielly (cant get anohter till later this weekend..)

HELP Im stumped

I think I"ll blow (with air compressor) thru the lines when I get claiper/MC off to clear debree

No pinched lines etc

[oldblue1968chevy]

I replaced the prop valve about a year ago (have to look at recipet)

braided lines arew a few years old, I looked at both sides to make sure they werent pinched i straigted the other side a lil

Idk im stumped and unhappy lol HELP

bmerdoc, sorry i missed your thread the first time

[BMERDOC]

So the only thing you haven't replaced several times over is the braided lines?

[crazy longhorn]

If your pushrod is too deep into the master cyl., it will also cause the fronts to drag (like partially applied on the brakes). To check, loosen up the master , & see if the wheels will turn more freely. crazyL

[oldblue1968chevy]

Few years ago I switched to disc brakes via getting parts off my parts truck (71 gmc 1/2 ton 2wd)

I put spindles from the 71 on my truck with matching balljoints. Got braided lines from ECE for disc brakes and put a new T and new steel line. For awhile I used the 71's prop valve. Well the brakes were sticking so I figured it was the prop valve-wrong new brass aftermarket disc/drum prop valve didnt change a thing. I tried new Mc and new calipers (not at same time) still nothing

Tried pulling Mc off the booster-still nothing

Ima put a new MC on and new calipers and blow with compressed air thru the lines (hard/soft) and retry again I guess


Idk HELP guys lol

[BMERDOC]

Originally Posted by crazy longhorn

If your pushrod is too deep into the master cyl., it will also cause the fronts to drag (like partially applied on the brakes). To check, loosen up the master , & see if the wheels will turn more freely. crazyL

He could definately be onto something! As much as I know about general brake knowledge, I just got my truck at the begining of the summer and haven't researched swapping my drums for discs toooo much yet but I do remember that the rod has to be modified or replaced. Did you swap this out? If its too long it could be holding pressure in the system causing your drag.

[oldblue1968chevy]

Its been a few years ago-But I believe I changed it out to the PB rod.

[oldblue1968chevy]

Probably unrelated but don't foget the white lithium on the caliper bolts. Believe it or bot, this was why my disc brakes would not release. Your problem sounds differetnt but just wanted you to know

(from a diff thread) im searching like crazy now lol

[oldblue1968chevy]

Should the bowls on the Mc be the same size (front/rear) same size? Uh thanks

[VA72C10]

(disclaimer: I am NOT an expert on brakes...not even close .... )

since it's been such an ongoing issue I think you have to start from scratch...

I'd take it all back off and verify everything (master, prop, rod length)

Then blow through the lines, bleed the lines, then verify the fluid comes out fine on both calipers with the bleeders...

[72lb4x4]

On disk brakes the pads are always in contact with the rotor so there's some drag. Shoes retract because there are springs.

New pads and new or turned rotors would probably reduce the drag, but I think there's no real problem here...

[oldblue1968chevy]

But shouldnt rotors/pads last longer than 10,000 miles? The inside of the rotor has grooves in it so does the inner pad (both sides?)

[crazy longhorn]

I had a bad booster on 1 , but it was very noticable(never made it out of the garage!) The 1st time I stepped on the peddle, it went down & stopped fine...but the peddle had to be PULLED back up before the truck would move? All the link parts seemed to work free, so the booster got chit canned & I went manual disc(this required a different master). The Old Longhorn has been that way eversince If I need a power brake , the lever is in my right hand....drop it a gear or 2, & let the clutch up! It sounds like something is holding residual pressure on the system.....could be a pushrod lenght issue, or hoses(internally collapsed)? Did you use new banjo bolts,or check for any rust buildup inside the bolts ,that would restrict the flow? Remember, that you can put the pressure IN with the peddle, but there is no leverage to get it back OUT. The only thing that slightly moves the pads back away from the rotors , is friction from the rotors turning. Another thing I saw mentioned , was clean & lubbed pins & slides. If that end is working properly,you should be able to 1st squeaze the pistons in , & bolt the calipers back on......now before you step on the peddle, take the caliper in your hand & you should be able to slide it on the pins, with very little effort. I use anti seize compound on the slide parts(a little dab will do you!) I do beleive you will need to turn or replace the rotors, & install new pads to make that job "as it should be". Best of luck,crazyL

[oldblue1968chevy]

Yes, new brakes will be installed IF/when i ever get it fixed

so theres a diff in power/non power MC???

[crazy longhorn]

Originally Posted by oldblue1968chevy

Yes, new brakes will be installed IF/when i ever get it fixed

so theres a diff in power/non power MC???

The diff will be in the bore sizing on the master(was on the '75 parts that I used on my longhorn anywho). This will have more to do with the peddle feel tho(smaller bore on the manual brakes, as you dont have the booster to help push the larger piston). In my setup, I used everything from a '75 C-10, & routed the lines & hoses the same. I think you just need to be sure that all of your lines/hoses are clear, slides are lubed/free, & check the insides of the banjo bolts for any rust /crud build up. Also, check that pushrod.....if you take the master loose from the booster, so you have about 1/4" or so clearance, you can push it by hand toward the booster. If the rod touches the piston before the master bottoms on the booster, the rod is too long. Hope that helps a bit....crazyL

[oldblue1968chevy]

Figured it out. (I think) I ordered 67-70 stainless hoses. They DONT have the banjo bolt thing and dont route good so they bind and pinch just a lil when the tires are turned and dont let the fluid out.

Ive got a set of 71 hoses ordered i'll get em tomroow. gotta find the banjo bolts now lol

Anyone want some stainless braided drum brake hoses

[crazy longhorn]

I think you just might have it "on the run" I have done brake work, since I was 15yrs old (thats going on 40 yrs now)....I sure dont claim that I know all, but what I have seen is a good bunch of guys , layin a good bit of info....take it all for what its worth & use it, then send it on to the next generation I wish I had my fathers patience teaching....that old man could watch the mistakes, & ignor them! It took him some time,but when it didnt work, he would say "well kid, take it back apart, & see what you find wrong with the mix" When I was a teen(about 100 yrs ago), It whizzed me off, that the old man didnt tell it to me.....but he knew, I do to that the best lessons you learn in life....sometimes you learn em the hard way that old man taught me how to think about what I was playing with. Off my soap box...best of fun, & let us know how she goes. crazyL

[oldblue1968chevy]

Will do longhorn. Hoses should be in after lunch tomorow. Then I"ll have to try to find a banjo bolt and then go from there?

We'll see

Ps, how ya like that camshaft longhorn? Id like to run it with my 355 soon as the funds are availible to maek the swap etc

[crazy longhorn]

Originally Posted by oldblue1968chevy

Will do longhorn. Hoses should be in after lunch tomorow. Then I"ll have to try to find a banjo bolt and then go from there?

We'll see

Ps, how ya like that camshaft longhorn? Id like to run it with my 355 soon as the funds are availible to maek the swap etc

She runs good, torkey as hell, but noisey.....I would maybe opt for a Lunati Voodoo , in about the same grind Hind site is always 20/20, but I think hyd roller next trip. Best of fun, crazyAL

[BMERDOC]

When you install the hoses get the flare nut finger tight so it will just still rotate. Make sure the wheels are pointed straight and tighten the banjo bolt first. Then finish tightening the flare nut making sure that the hose doesn't twist.

[72lb4x4]

Get new rotors and you'll stop eating pads IMHO...

Do you have another, late model car/truck? Jack a front wheel up and spin the tire. Disks are meant to drag just a bit.

[crazy longhorn]

Originally Posted by BMERDOC

When you install the hoses get the flare nut finger tight so it will just still rotate. Make sure the wheels are pointed straight and tighten the banjo bolt first. Then finish tightening the flare nut making sure that the hose doesn't twist.

Good advice Doc No twist the hose...crazyL

[oldblue1968chevy]

I understand that they'll drag a little, but these were too tight..

The hoses are for drum brakes and dont route properly either I dont think..