Brake job mistake

[boombots]

Master was about 170 total with shipping btw.

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[boombots]

I will look into bench bleeding before installing though. I didn't when I did my trucks master but I guess it can't hurt.

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[D1JL]

Since you are planning to remove the old master before installing the new one.
Why not try to bench bleed the old one.
This will not only prove the status of the old one, it will allow you to practice on bench bleeding, and it will not commit the new one to a status of USED, if not needed.
After all, your problem could be in the ABS module.

BTW, I am just trying to help as you asked, you do what ever you want.



Dave

 

[boombots]

Good point. Thank you. I'm fairly confident in my mechanic skills but still have tons to learn as I don't have that many years experience with the wrench. I'll give her a try. Doesn't feel abs related but new cars do weird shit...

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[aballphoto]

Good point. Thank you. I'm fairly confident in my mechanic skills but still have tons to learn as I don't have that many years experience with the wrench. I'll give her a try. Doesn't feel abs related but new cars do weird shit...

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When you did the brakes, did you compress the pistons one at a time, or do them all and then install the pads and rotors? I'm just curious, because I've done a ton of brake jobs before, but not much on newer cars. I've never run into a problem like this, but seeing as I'm about to do the brakes on my Fist, I suppose I should be ready for any weird things it might do.

 

[D1JL]

When you did the brakes, did you compress the pistons one at a time, or do them all and then install the pads and rotors? I'm just curious, because I've done a ton of brake jobs before, but not much on newer cars. I've never run into a problem like this, but seeing as I'm about to do the brakes on my Fist, I suppose I should be ready for any weird things it might do.

One at a time is best.
Most important is to open the bleed valve on the caliper while compressing the piston.
This prevents fluid from being forced back into the ABS module and also the master as this is where damage can be done.



Dave

 

[boombots]

I did one at a time but didn't open bleeders and with the fluid having been topped off by ford and the cap on the pressure I think caused issues.

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[aballphoto]

One at a time is best.
Most important is to open the bleed valve on the caliper while compressing the piston.
This prevents fluid from being forced back into the ABS module and also the master as this is where damage can be done.



Dave

I did one at a time but didn't open bleeders and with the fluid having been topped off by ford and the cap on the pressure I think caused issues.

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Thanks guys, yeah sounds like a opening the bleeder can save a lot of headaches later. I don't mind bleeding, but replacing masters or chasing ABS issues, no thanks.

 

[boombots]

Agreed. I've never opened bleeders before but it seems it finally bit me this time. I'll report back tomorrow with hopefully good repair news. I wanted to do it today but college football and beer happened.

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[boombots]

Got the old master out. I've done a master in an f150 and explorer and had a new experience this time. Either a signal that it was broke or I screwed up because this system works differently. I unhooked the master, pulled the lines, and when I pulled it from the booster the piston shot out of the master entirely.

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[boombots]

Also fluid inside the booster. The master definitely was leaking. Hopefully I can save the booster and get it clean

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[boombots]

Took booster out and cleaned it and reinstalled with the new master. Attempted a bench bleed but noone had the proper fittings to do it so I tried anyway.

Bled the brakes furthest to closest to the MC. Still not working. The pedal is rock hard with the car off and starts sinking with the car on. Seems to sink faster than before but not 100% sure.

The old master had to have gone out as the piston shot out and there was fluid all inside the booster.

Now I need to figure out why it still doesn't work. Maybe the booster? Not sure. I'm almost certain it's not air as there was no way air was introduced into the system during the initial brake just. I just did the standard pads and rotors procedure. With me "ruling out" air I doubt there is an abs related issue. No codes either.

Could a caliper be bad and not leak fluid?

The rotors seemed the same thickness as before and the pads seemed OK as well. The pistons certainly are not over extended on the calipers.

I'm at a loss. Not really looking to drop a pile of cash for Ford to diagnose it and fix it either...

Also need to figure out if I should bleed the clutch after doing a master...

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[D1JL]

I do assume that the car is on stands.

Just to be clear,
With the car on/running and the parking brake off the "BRAKE" light (red brake word) is not on at all?
As well there are no other dash lights on?

I hope you preformed a gravity bleed just to make sure you got the air out because you did not bleed the master before installing it.

Yes, if you ran the reservoir out of fluid and in your case you removed the master, you will need to bleed the clutch.
Also sense you removed the booster, I hope that you did not move the brake pedal when reinstalling it.
This could cause misalignment of the pedal position switch and cause you even more problems.




Dave

 

[boombots]

Car on stands. No light at all. Made sure not to move the pedal as well. I did gravity bleed but no fluid gravity bled from the front.

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[D1JL]

Car on stands. No light at all. Made sure not to move the pedal as well. I did gravity bleed but no fluid gravity bled from the front.

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The master is divided into two parts.
The front brakes should be the back section.
Follow that line over to the ABS module.

Will it gravity or pressure bleed at the input of the ABS module?
If yes, the master should be OK .




Dave

 

[Intuit]

As a test, is it feasible to temporarily remove ABS from the hydraulic system? The brake hydraulic system is pretty simple.

The only thing the booster does is use the surrounding atmospheric pressure to place additional force upon the master cylinder. The booster is a totally independent system and can be ignored unless running the engine has no impact on braking performance.

 

[boombots]

I'll check the gravity bleed at the abs tomorrow. Hopefully the master isn't jacked because I didn't bench bleed. I've done my f150 and explorer and didn't bench and both had abs. I keep thinking its something about the brake job but I can't be, the rotors and pads look fine and don't see any leaks either...

If no luck tomorrow its going to ford. I don't have a lot of time and I'll be out of town the next few weekends. That and I'm stuck driving my truck with a bad head gasket... That project was suppose to start this weekend... Not looking forward that that repair bill.

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[Intuit]

https://en.wikipedia.org/wiki/Anti-lock_braking_system#Components

Valves and Pump ?

https://www.amazon.com/Aeroquip-FBM...310&sr=8-15&keywords=hydraulic+brake+line+cap

I don't know how ABS releases pressure without there being a return-line or reservoir. *IF* there is a return line of sorts, and the above fits, that may cap it off for testing purposes.

The fact that your master cylinder's piston shot out, indicates that there may have been some back pressure in the system? Is that normal ? Could it be related to the ABS module ? How do you determine the state of these valves ? How do you manually actuate them ?

 

[boombots]

All the lines were unhooked. It even partly drained. Pressure was strong. That piston shot out with force and the fluid was so compressed there was a steamy smoke rolling out. I dont have a ton of brake experience but I've done 2 other masters and this definitely didn't happen then.

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[D1JL]

Valves and Pump ?

I don't know how ABS releases pressure without there being a return-line or reservoir. *IF* there is a return line of sorts, and the above fits, that may cap it off for testing purposes.

The fact that your master cylinder's piston shot out, indicates that there may have been some back pressure in the system? Is that normal ? Could it be related to the ABS module ? How do you determine the state of these valves ? How do you manually actuate them ?

The valves and pump (motor) are all in the ABS module.
This module along with the position and accusations of the valves can only be accomplished with a professional ABS diagnostic tool (I still use my Snap-On).

The ABS module is not repaired but only replaced.
If it is replaced, it must first be flashed/programmed by the dealer before it can be used in the car.

I believe the piston coming out of the master is normal as the photo in the service manual shows it held with zip ties before installation.

Dave