Brake issues! Help save this rig from going to the scrap yard!

[delexploder]

New doesn't matter, if you pinch them you are creating a problem ,it may take time to show up or it may do it right away, either way take it or leave it

 

[delexploder]

Also if you let your calipers hang from the lines or you stretch the one that goes from the frame to the block on the rear ( off roading or on a lift ect) it will do the same thing

 

[Juggernaut31]

Okay something else. if you have traced it down to one caliper. i once had to do this... i had a new caliper, that would not bleed out properly. it bled, no more air bubbles, etc. but i had the exact same issue. i did the crimp test, above, and traced it down to the passesnger side rear. no matter what i did, brakes for crap. almost no pedal, and you better not be traveling fast if you needed to stop.
new pads, new brake booster, new MC. all new fluid.....
anywho... what i finally had to do, (this was told to me, and it sounded stooooooopid, but i figured i would try anything at that point!), was to remove the caliper from the rear disc, (brake line still attached). I put a piece of wood, that i had cut down in place to "simulate" the caliper. i turned the caliper upside down, and had my wife pump up the brakes. low and behold, AIR!!!!!, i used the c clamp to close the caliper back in, put it back on the rear disc, and had perfect brakes to the day i sold it, almost 3 years later.......

 

[swshawaii]

Thats a great question, and one I faced a couple years ago. I had a bleeder break on a rear caliper while working on it once. The friend I was visiting at the time had a spare caliper we swapped it out with. Turns out it was for the other side and the bleeder was on the bottom. I replaced it with a new one later on.

So for those that don't know, the bleeders should be on top to allow air out, and not trap bubbles. On a gravity bleed, you can remove the caliper and turn it over to allow air out if needed.

 

[gmanpaint]

Thanks for the heads up on the soft line pinch test. If I think they need replaced I will do so.

In my case anything that helped finding the issue was welcome. I have no problem replacing faulty parts, but I do have a problem with replacing good parts.

 

[turboexplorer]

I know his point on the lines. But I wouldn't be SO concerned. When I say pinch it only takes a very small amount of pressure to hold it closed. You by no means have to gorilla man the vise grips on. The pressures are high yes but the surface area inside the line is almost nothing. If you can visually see and pinch mark or anything of the sort the test was not done right. gmapaint has plenty of sense to know this. And the lines are flexible for a reason they can move with all the turning and suspension movement 1/16" little squish won't destroy a line.

 

[BobWiersema]

A little pair of these guys would work nice without hurting anything.

 

[gmanpaint]

I know his point on the lines. But I wouldn't be SO concerned. When I say pinch it only takes a very small amount of pressure to hold it closed. You by no means have to gorilla man the vise grips on. The pressures are high yes but the surface area inside the line is almost nothing. If you can visually see and pinch mark or anything of the sort the test was not done right. gmapaint has plenty of sense to know this. And the lines are flexible for a reason they can move with all the turning and suspension movement 1/16" little squish won't destroy a line.

The pinch was done very lightly, just enough to close the I.D. to stop fluid flow. Since the lines are relatively new, they closed very easily. Old lines will be hard, and will crunch when you pinch them. Very easy to tell the difference between them.

All this info in this thread is great for the next person that has an issue and reads this thread, so keep it coming!

 

[quick50mustang]

I know you said you replaced the brake booster, but have you tried using a vacuum gauge on the inlet to see if it will hold vacuum?

 

[mic98xlt]

Surprised there has been no resolution to your problem. Very interesting thread such that I and others, are looking forward to seeing the outcome. I'm sure the results will be positive.

 

[PhantomFord]

did you get your brakes fixed?

 

[gmanpaint]

did you get your brakes fixed?

Haven't had the chance to get back to it yet. I do believe the pressure was set to high on the prop valve (600 psi) causing the master to bypass. I need to do some more testing on the pressure settings still.

 

[gmanpaint]

A good test run was done today.

With the prop valve pressure dialed in at 450#, the new flares done, a gravity bleed done, there was no brake peddle issues. It passed inspections today!

Can't be sure which was 100 percent the problem, but I'm still believing the pressure was just to high to the rears.

Super stoked that this problem is over ( Crosses fingers).

 

[Twiztid]

and the inspector was pretty cool too, but he just get's it from his uncle TWIZTID