Can't get the brakes bled | Ford Explorer Forums - Serious Explorations

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Can't get the brakes bled

runderwo

Well-Known Member
Joined
August 4, 2009
Messages
141
Reaction score
3
City, State
Tulsa, OK
Year, Model & Trim Level
91 XL
This is driving me nuts. I had to replace my front to rear brake line due to rust about a month ago. Since then I have tried everything I can think of to get the air out of the brakes but I still have a mushy pedal that goes to the floor under vacuum boost.

I have:
Bench bled 2 master cylinders
Bled all 4 wheels in the correct order with speed bleeders
Bled all 4 wheels with standard bleed screw method and a helper
Knocked on the calipers with a hammer
Tried to get the RABS to pump by turning the rear wheels with the motor on while pressing the brake

Fluid runs clean/clear at all 4 wheels with only a few small bubbles.

After all this, if I put my head between the driver's tire and the motor, I can hear gurgling in the brake lines between the master cylinder and the combination valve when the pedal is depressed.

As a last resort I wanted to try gravity bleeding, but I can only get a drip out of the front wheels' bleeders, at the rear wheels there is no action, probably because of all the humps in the brake line.

I will gravity bleed the fronts anyway when the weather gets better. I just wanted to know if anyone had any thoughts on what I am doing wrong.
 



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Unless there is a leak somewhere (like bad flare on the new line etc) I can't imagine why you can't get the air out. It's not a complicated brake system. Only thing I can think of is that the master might be bad.

You do have the calipers on with the bleeder screws near the top right? (I'm not even sure you can confuse the two)
 






I tried two masters, one is a used OEM, one of them was a new Raybestos OEM, unfortunately, on the new one of the threaded parts just broke off because of the cheap metal. :mad: But I wasn't getting a hard pedal with that one either.

Yes I have the calipers on with the bleed screws at the top.

I didn't flare the new lines myself, I just used the lines that screw together. There are no fluid leaks at any of the fittings, so I don't see how I can get air in there, right?
 






I agree that it doesn't make any sense. Only thought would be it is in the combination block connections or you have a leak at one of the wheels themselves (not bleeder)
 






Is everything Dry that you replaced? No leaks along any fittings or brakelines?
How did you bench bleed the master? Was it on the car and pump Fluid out of the fittings back into the reservoir works the best.


Have you bleed it with the Tube in a glass method?
 






Yes everything is dry.

I bench bled the master in a vise on my bench. I used a speed bleeder in the rear port and bled the front one by covering it with my finger to prevent air from sucking in.

I don't know what the "Tube in a glass" method is. If you mean did I attach a hose to the bleeder, submerge it in brake fluid, and hold the container and hose higher than the bleeder so that the air bubbles out when fluid is pushed in, then yes, that is what I did.
 






Yeah, you don't need to hold the container higher then the caliper. The tube just has to be submerged in brake fluid. The bleeder can't be WAY loose.

After bleeding the Master on the Bench, you didn't let the reservoir run dry when installing it in the car , did you?
Install the master on the car and use this to bleed. Screw the fittings in teh master with the hoses running back into the Reservoir. Pump pedal until bubbles stop. With Pedal Held down a bit, unscrew the bleeder and screw in the Brake lines THEN let the Brake Pedal up. Now go and bleed the Calipers. Rear passenger first , rear drivers, Front Passenger, front drivers.
http://www.amazon.com/Thexton-346-Master-Cylinder-Bleeder/dp/B000P9CP4U
 






I loosen the bleeders about 1/4 turn, just enough to see decent fluid flow.

We keep the master at least half full. To my knowledge it has never drained.

Thanks for the link. I searched for something to fit that M12 x 1.00 front fitting but couldn't find anything anywhere. Didn't think that it would be easier to find as part of a MC bleed kit!
 






I loosen the bleeders about 1/4 turn, just enough to see decent fluid flow.

We keep the master at least half full. To my knowledge it has never drained.

Thanks for the link. I searched for something to fit that M12 x 1.00 front fitting but couldn't find anything anywhere. Didn't think that it would be easier to find as part of a MC bleed kit!

Sorry it's not working for you.
I did a Master in the 'X' two years ago and it was a snap. Then a few months ago I had to do the rear steel line and changed the Axle Soft line. Aside from it being tough to get at, The bleeding went fast and easy.
 






Try parking it on a pretty steep downhill grade and gravity bleed the front and park uphill on a steep incline to do the rear. The grade should help push the fluid over the humps in the line. This may help ... it has helped get me through stubborn bleed jobs before. I always completely remove the bleeder screws on both calipers when I do this. But make sure you keep an eye on the fluid as it runs low after a few mins with them open and if you let it drop too far you'll suck in more air than you have now !! You could also try taking a piece of clear tubing ( I use aquarium hose ) and open one caliper at a time and hook the hose on the end of the bleeder, put the other end in the fluid in the master cylinder and just slowly pump until you see no more bubbles in the line. Its better to have someone stand there to help you hold the line in the master, because once again you could let the line come out of the fluid and it suck more air than was originally in it. Hope this helps and good luck !!
 






Still haven't gotten the MC bleed kit in the mail yet, but I tried bleeding again today. The rears came up clear, the fronts gave me the trouble. I replaced the bleed screws (7/16 x 20) and was able to get the right side 99% bled (still a little bubble here and there). But bleeding the driver's side caliper, it comes out like soda even after putting 2 bottles of fluid through it. I have no idea what the deal is. Nothing is leaking on the ground so where is all the air coming from and why is it just the driver's side?
 






I tried bleeding it with the engine running. Under boost it bled a lot quicker and I was able to get the air in the driver's caliper cleared out. Then I went and rechecked all 4 wheels and it was clear at every wheel, finally!

However, I still have the original problem where the pedal is hard when the motor is off but it goes straight to the floor when the motor is running. It doesn't seem like a bad MC which would bleed slowly to the floor even when the motor is off. Also, it does in fact have full braking power, bringing the truck to a screeching stop about 3/4 of the way to the floor. (As far as I can remember, it used to be that a screeching stop was when it was about 1/2 way to the floor, and I would have had to stand on it to get it to go to the floor while running.)

So I guess it's the pushrod that is out of adjustment, but I can't figure out how to get it to turn. I put a wrench on the machined part and tried to turn the star part with the tightest fitting wrench, but it just rounded right off.
The pushrod looks like the one on this linked page but 9mm was waay too big, 11/32 was the tightest fit I had. Maybe it's time for some PB blaster and vise grips?

http://www.explorer4x4.com/discswap.html
 






perhaps there is water seeping into the system or there needs to be some brake adjusting? not sure. or the MC is gone bad. or try to bleeding differently? is the brake booster any good? im just going of insticnt im still a noob though.
 






Drivers side has that dopey soft hose with the two fittings. No leakeage at the fittings ? Soft hoses look good?

I can't imagine what the heck is going on.
 






I got it bled, the key was to bleed it with the motor running. Now the pedal travel seems to be the issue.
 






I got it bled, the key was to bleed it with the motor running. Now the pedal travel seems to be the issue.

Pedal Travel? Are you rear brakes adjusted up properly? That's usually the cause for a low pedal
 






I went out and adjusted the rear brakes. One of the star adjusters was frozen. Now with the motor off the pedal travels about 1/8 of the way and it's hard as a rock. But it still goes straight to the floor with the motor on.
 






The pushrod should stick out 1 inch from the face of the brake booster measured from the MC stud bolts. If that doesn't help you may want to look at the RABS valve as a source of pedal fade.
 






I never thought that it was a problem, but my pedal has always(at least in the four years that I've had my X) gone to the floor when the engine is running if I press it somewhat gently. If I am driving, and have to suddenly hit the brakes hard, it only goes about halfway down. I don't know if there is some sort of valve or something that "locks up" if you hit the brakes hard or something? Just hoping that I don't have a problem!
 



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I was having a similar problem.Every 4th or 5th brake application the pedal would fade to the floor when pushed slowly. Pumping the pedal would bring the pedal back up. I finally diagnosed it to be an internal leak in the master cylinder.After replacement and extensive bleeding the problem is gone. The RABS valve keeps the rear wheels from locking up on hard stops.It can be a source of pedal fade but needs to be diagnosed as the replacement part costs around $160.00 with core exchange.
 






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