Hi folks. I typically just view the forums and read but really need some help.

How in heck do you get the sensor off the brake fluid sensor (it's hooked/connected to the master cylinder)... I can't get the old one off Is there a secret?

Also, I failed to bench bleed the new master cylinder. Is there an easy way to get the air out of the lines?

Thanks!

 

Dunno about the brake fluid sensor, but a can drive bubbles from the entire system. How to videos are helpful here.

 

Wanna say the sensor was threaded in when i changed buddys mca

 

You can 'bench bleed' it on the truck. Make sure the master is level or the front is lower than the rear, raise rear end of truck if needed. Short pumps on the pedal, 1-2 inches. If you haven't started trying to bleed at the calipers yet this will get you a solid firm pedal once the master is bled. If you've already started trying to bleed calipers there will be air in the lines and/or calipers to deal with.

 

As for the sensor, are you talking about the one on the master cylinder or the reservoir, and are you trying to remove the sensor of just disconnect the connector?

 

The reservoir sensor unit will pull off toward the drivers fender. The lead not be detached. It's a weak clip that just snugs up under the res jug.

The connector on the outboard forward side of the Master cylinder will disconnect and the sensor is threaded in and should back out easily. Thinking 14 or 15 mm wrench.

If your replacing the master cylinder, the easiest cleanest method is to get the kit (10 bucks on the HELP rack) and screw the plugs into the ports after the line is removed.

I use the same kit to put in the bleed ports in the new MC and run the hoses directly back up to the res and bleed it with pedal after the MC is reinstalled only going in 1/4 way down. Be cautious not to over extend the pedal as this could damage the MC.

Take your time and let the bubbles disipate between pumps. When no bubbles appear reconnect lines, fill the res and crack all bleeders on wheel calipers. Eyeballing the res level.
Refill the res. Tighten calipers and check for feel. Gingerly pump the brakes to get the calipers seated and refill the res. If the pedal still feels sponge, start at the driver front, pass front, driver rear and then pass rear. Use a new bottle (quart size) and put a hose on from the bleed screw and submerge it in the bottle. Should only take a few pumps of the brake and tighten bleeder. Move on. You can do it by yourself this way but it goes better with a drinkin buddy in the cab. When doing this line wrenches are very handy and will make the job easier.

Denny

 

No need for plugs or special fittings to 'bench bleed' on the truck. Connect the lines and pump, short strokes. As long as the master is level or the front is lower all the air will go up into the reservoir. I've done it dozens of times and no air anywhere in the system. In some cases where the lines go upward out of the master you might get some air trapped there, just tilt the vehicle so that the air runs up into the master or compress the caliper pistons, one front and one rear, and the air will be pushed up into the reservoir. On vehicles with rear drums I set the parking brake before starting the work, releasing it after bleeding the master pushes any air into the master and to the reservoir.

 

I'm calling bull**** on this method. Any air in the filled Master cylinder will not surface. It will go into the lines. That's the hand I'm playing.

If it works for anyone, they're new MC is junk.

Educate me. That's what this forum is about, and I say so respectfully.

Denny

 

Those were the questions that came to my mind as well.

If you are talking about inboard facing threaded sensor on the hydro boost unit (the sensor that is pointed toward the engine), then it is worthwhile to not only remove, but replace that sensor with a new unit, especially if yours is of the original design of your 2000 model year. The original sensor was made by Texas Instruments, and the membrane in that sensor eventually fails, allowing brake fluid to come into contact with constant hot 12v, even when the truck is off. This has been the cause of many a Ford fire, and at least three related safety recalls. Earlier recalls simply installed a fused jumper harness. But the last recall called for an updated brake pressure sensor (the application of brake pressure on this sensor is to automatically disengage speed control).

If that is the sensor you are talking about, wrench it off, and replace it with a new sensor and fusible link from a kit that Motorcraft sells for relatively cheaply (I've noticed that federally mandated recall parts seem to have less mark up than normal parts).

If you are talking about the sensor in the fluid reservoir facing the driver's side fender, why are you trying to remove that sensor? Isn't it enough to just unplug the harness?

Hence, I have the same questions that 88-E-350 has... more questions than answers.

 

You start with calling my method bull****, then make an ignorant statement, then follow that up with another one, and another one. Not a good way to open to "educate me", but I'll respond for others who may be in doubt.

I've done it on dozens of masters successfully. I've done it with clutch and brake masters on cars, trucks, bikes, trailers, forklifts, etc; not one problem yet. Air can't go down the lines unless you open a bleeder or have a leak, it's a dead end. The same port that lets fluid in & out of the cylinder will let air out which will rise to the top of the reservoir and be replaced by fluid, just the same as bench bleeding with plugs on the outlets. On one occasion I installed a master in the evening and did nothing but fill the reservoir, by morning it had bled itself almost entirely.

 

That is not the hydro-boost unit, it's the brake master cylinder.

 

First off,

Mister Y2K above has more knowledge on the 7.3 and it's structure than 89 percent of this forum.

Secondly: If you think you can throw a dry master cylinder on our "OUR" truck without bleeding it and just fill it up and wave a magic wand.............. Yep.

Your dead wrong.

In effect your saying I can throw one in a vice nose down instead of turning my truck on a rotisirrie. Fill it up with fluid, and it will magically purge the compression cylinder of air?

Beg to differ. That first stroke is nothing but air. The next is the worst and the third is like watching an old guy throw up.

Yes you have to bench the cylinder. That's why the tag on it when you buy it says that.

Enjoy your weak brakes.

Guess that's another arrogant statement.