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First off yes I've read other threads and yes I've tried it. So my breaks were bad when I bought the truck same thing I have now I went to bleed them and the bleeder were all stuck closed so I got all new drums wheel cylinders and shoes and new calipers and pads in the front so I could bleed them properly and the master is new but not by me I did bench bleed it and there was air in there I've bleed all the tires until new clean fluid comes out (two+ big bottles) no air comes out anywhere. I read that the rabs module can dump fluid when it goes bad so I bypassed it 100%. I have no fluid loss. The next thing I'm going to do is plug the master and hit the pedal to see if it holds pressure. If it does the only other idea I have is there's an air bubble trapped in a bend somewhere that pressurizes at first but moves past the fluid under pressure is that something that can even happen if so how do I fix it and if not what the hell is going on here????? Any ideas you may have I'm all ears
Brakes are not my thing but I know they can be a PITA to bleed, sometimes. Like you said, you might just have air in your lines. Keep bleeding. One-bolt, my truck also makes a hissing when I first apply the brakes, then goes away as I get a solid feeling pedal. I hope my booster isn't on it's way out.
A) When you bleed, have your helper jam HARD on pedal. You call go, crack bleeder open, they stomp and hold, you close bleeder. The pump-up method CAN work, but it can cause problems.
I just went through this with my 97 Wrangler. Painful until i figured it out. The proportioning valve was the problem. If yours has one, i can almost guarantee that's the problem. I'm assuming it does :-/ In my wrangler, there was a way to manually prevent it from doing it's job so that i could finally bleed properly.
B) Is your brake light on, on your dash when your e-brake is off. That's the "check engine light" for the proportioning valve.
A proportioning valve will block off the front or rear if there is a catastrophic drop in pressure. The pressure of the good end of the system, closes off the bad end. It's a little shuttle with a detent in the middle. When the shuttle is centered (normal state), flow is appropriated as per design (eg. 70% front/30% rear). There is a normally-open switch with a plunger that goes in the side. When the shuttle moves one way or the other (abnormal state), the plunger depresses and closes the switch, triggers the parking brake light on your dash. The way to reset the shuttle is to jam on the pedal HARD a few times, once potential catastrophic leak is fixed. Well cracking your bleeder and bleeding with improper methods can trigger this shuttle to move. Pressure wise, the valve sees a catastrophic loss of pressure. I took mine apart and detailed it. All for naught. Prop valves stay good forever. What you have to do, is disable the shuttle. You basically have to lock the plunger or put something like a nail in there so the shuttle can't move right or left. Bleed. Then you're good. One sign of a shuttle to one side is not getting good flow/stream when you do bleed. Gravity bleed all four first, in proper order: RR, LR, RF, LF. Gravity bleed is just cracking bleeder open until a trickle comes out on it's own. Once this is verified, THEN do a proper bleed, with the pedal stomp technique.
My ebrake dash bulb on my 5 speed, that i use almost everyday for 4 years, goes out during my big brake install process. What the f'in chances hahahaha
In my wrangler, there was a way to manually prevent it from doing it's job so that i could finally bleed properly.
The proportioning valve was the problem. If yours has one, i can almost guarantee that's the problem. I'm assuming it does
There is no proportioning valve as illustrated in the photo above on this vintage truck. The F-Series/Bronco used RABS (Rear Anti-Lock Brake System). There is an electronic control module behind the glove box and a hydraulic valve located on the driver side frame rail to modulate pressure to the rear brakes.
First off yes I've read other threads and yes I've tried it. So my breaks were bad when I bought the truck same thing I have now I went to bleed them and the bleeder were all stuck closed so I got all new drums wheel cylinders and shoes and new calipers and pads in the front so I could bleed them properly and the master is new but not by me I did bench bleed it and there was air in there I've bleed all the tires until new clean fluid comes out (two+ big bottles) no air comes out anywhere. I read that the rabs module can dump fluid when it goes bad so I bypassed it 100%. I have no fluid loss. The next thing I'm going to do is plug the master and hit the pedal to see if it holds pressure. If it does the only other idea I have is there's an air bubble trapped in a bend somewhere that pressurizes at first but moves past the fluid under pressure is that something that can even happen if so how do I fix it and if not what the hell is going on here????? Any ideas you may have I'm all ears
When you bench bled the master, how far in were you able to push the piston once air was gone? Did it go from full movement down to 1/4" (give or take)?
When you bled did you run tubes back in to reservoir or use plugs?
Bleeding is a huge pain in the *** because air can leak past the threads at the bleeders. I have had success by putting grease on the bleeder threads and then following the standard bleeding technique.
Bleeding is a huge pain in the *** because air can leak past the threads at the bleeders. I have had success by putting grease on the bleeder threads and then following the standard bleeding technique.
Btw it's BRAKES not BREAKS
If you have the right kit, those fittings are tight. I've always made my own set with brake tubing and the right fittings, making them long enough to be fully submerged in the reservoir. I would never use anything to perfect the seal of the plugs past some silicone brake assembly lube. Any other grease may not be compatible with a brake system, causing who-knows-what kind of havoc.
The brake MC needs to be bled carefully, not going all gangbusters on it. Also, I've seen this solid plug method but I have to say, it's just like bleeding the system with the bleeder fittings closed. Nothing is happening because there is no place for the fluid & air to move to as it is trapped by the plugs.
I will point out that in today's world, probably about four in ten new MC's off the shelf will be bad. Poor rebuilding practices which includes a splash of paint and a new reservoir before boxing an otherwise defective MC for sale. Even new MC's on the shelf are subject to a higher failure rate than I would like to see.
One thing that most people overlook is the clearance from the MC piston to the actuating rod. If the MC piston cannot return fully to the unactuated position, you will never get the system to bleed properly. Piston depth between new and old MC's should be checked and the rod tip adjusted accordingly.
Alright, I'll put away my shop instructor's smock and clipboard now. Back to your regularly scheduled thread in progress.
05-23-2017, 07:55 AM
