Brake job mistake

[boombots]

I've done tons of brake jobs before but I think I finally jacked one up... Pedal now sinks to the floor. It is still very firm if you pump it but applied pressure makes it sink.

I put new pads and rotors on all four corners. Where I went wrong was not taking the master cylinder fill cap off. Retracting the pistons with the cclamp and tool for the rear forced fluid out of the cap. During the process it must've blown the internal seals out in the master.

No leaks anywhere. I pumped the brakes for 5 minutes to check for wet spots and I see nothing.

Could I have blow the master or am I missing something here?

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[CanadianGuy]

With no leaks it sounds more like air in the system. Unless the master in the FiST is that weak. Have you tried bleeding the system? Worse it waste some fluid and time to prove its the master.

 

[boombots]

I haven't bled yet, unsure how air would've gotten in, but I agree it's worth a try. Pedal didn't feel like air in the system, it feels like a leak. I can't see how our master is that weak, but who knows, I've never had a master overflow with a cap on either.

Thinking back, I did try a c clamp on the rear piston before realizing it took that goofy tool. I'll pull that one for closer in, maybe I messed up the piston on that calipers.

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[BBock]

I feel ya man I somehow messed up doing stainless steel lines couple weeks ago and had to get a new master, so hopefully yours is a simple fix good luck.

 

[LilPartyBox]

definitely bleed it just for giggles but did you compress all four pistons with the cap on the master? you should be OK though as I've heard the caps have to be vented somewhere or else how would the fluid level change as brake pads wore down...makes sense or else how would brakes work at all?

 

[boombots]

I agree, you'd think the cap seal wouldn't be stronger than internal seals. It's possible maybe a boot ripped on a piston, those rear ones require you spin them in rather than press. Maybe I messed that up. Front ones I used the standard c clamp method. All 4 with the cap on.

Thinking back, I did knock one caliber off where I had it balanced when I was hammering and torching my rotor off (it was rusted on pretty good). I inspector for any leaks from the line and it looked good.

I'll bleed and then start pulling one wheel at a time for inspection of the line and pistons. If that checks out I guess maybe the master went out.

Odd as I've never has this happen on any of the vehicles I've done before.

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[willsolo]

I had the same issue too, and here is how to fix it:

I have bled these systems many times and never needed special tools or the dealer.

I would suggest that you gravity bleed the system first.
One wheel at a time in this order, RR, LR, RF, LF.


After that bleed as normal with one person on the pedal and one at the wheel.
It is best to use a clear plastic tube on the bleed valve nipple so you can see the fluid.
Do NOT pump the brake pedal, this only puts air back into the system.
Just one press then bleed and repeat on all wheels until there is no air.
Always do RR, LR, RF, then LF.

You do not need to do the gravity bleed again.
However then do the same procedure again with the engine running.

This method has worked for me every time without fail.
Or you can tow it to the dealer, it's your money.



Dave

 

[LilPartyBox]

Get a Motive Power Bleeder. I have one for my wife's car and will buy one for the FiST when the time comes

 

[boombots]

I've been working on bleeding now, not seeing any air. The rear brakes are hard to bleed. With the bleeder open you still have to stomp hard to get a little fluid to come out. Gravity bleeding the back had almost nothing come out. Odd.

Ive had no luck on power vacuum bleeders. They always left me with air in the system.

I'll rebleed them again but then I'm going to try and pressure check the system to confirm I don't have a small leak that I'm missing.

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[willsolo]

Try what I posted as well. The symptoms you are having are the same that I was having with my brake change.

 

[boombots]

Just did a full bleed procedure. Same symptoms exist as before. It sounds like a have a pad dragging, but I'm sure if I had brakes they would push and retract as they should.

This is all very odd to me.

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[boombots]

Is it possible to have a leak and not see fluid. I'm fairly confident is not air. I don't see how air could've enter the system, and I've bled it. It also doesn't feel like air. Air gives a soft feeling that eventually makes a firmer pedal as it gets compressed. This pumps up firm and as you keep applied pressure it slowly sinks. It feels like a blown line or wheel cylinder leak or the like. Just not a hint of fluid leak that I can detect.

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[CanadianGuy]

I assume you tried both engine on engine off and handbrake on handbrake off?

I have never seen a leak without fluid, not saying I have always easily found the leak. But ya if no leak than the master is shot allowing fluid around it loosing all pressure. Strange.

 

[boombots]

Yeah. I've driven it around the block, the handbrake doesn't seem to work that great either.

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[D1JL]

As you described the way that you originally forced fluid back into the system, it is possible that you dislodged a valve in the ABS module.
The only way to know for sure in to use a true professional diagnostic tool that checks the ABS system.

There is also a built is pressure deferential valve, this is to prevent total loss of brakes in the event of a catastrophic brake failure at one wheel.
The system may think you have a leak and shut down half of the system ( have seen this before).
This should also set an ABS trouble code, again a ABS diagnostic tool is required and it should set a brake system failure light.

There is a lot of Q&A to figure this out.
If you wish, PM and I will give you my number and help if I can.

BTW, disk brakes do not have return springs so pads dragging is normal.


Dave

 

[boombots]

I may hit you up. I have no warning lights. I'm the kind of stubborn person who will fix this myself rather than consider a shop. Even if that means many angry afternoons and cursing the engineers at Ford.

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[boombots]

I did order a new master. I'm 99% sure that is the issue. I've had air in the lines and such before and this is not that feel in the pedal. Feels just like a leak or blown master, and being I've thoroughly checked the lines and calipers... Only 2 oem masters in the country so it's taking forever to get in... Ugh

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[boombots]

Btw, I'd avoid Tasca Ford. I ordered the master there. Cheap. No mention of a special order. I called they said it's be to them Wed and probably to me Sat. That got moved back and I ended up having to pay 70 to overnight ship it to get to me for the weekend... Ugh. That said I guess it was still a few bucks cheaper than local, just a pain in my ass.

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[D1JL]

I hope you took the master off your car and bench bled/tested it before you spent all that money as that is an easy test to do?

BTW, this is a procedure you should do before installing a new master on any car.
You can buy a bleeding kit at any auto parts store.




Dave

 

[boombots]

I've never bench bled but there is no way there is any other leak. I've had no time to even touch the car work has been busy, that's why i just ordered it and need it here this weekend.

I know I should have done more testing but time is short. I know my luck it won't be the master, but we will see...

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