2017 Master Cylinder / Brake booster failure

[7GenTex]

Same issue last December on '17. 3 wks for parts. Used it as an excuse to buy a '20 for a spare. Going to sell '17 one day.....been such a good truck that I hate to part with it.

Mindreader...................??

Servicing dealer has a '20 Leadfoot SCREW on the lot.................(though as a replacement)

 

[FordTechOne]

Weird.................

From the NHTSA:

https://static.nhtsa.gov/odi/rcl/202...0V332-1472.PDF

"Investigation of field return parts found the causes of the brake fluid leak to be
brake fluid contamination that could interfere with rear cup seal function or, to
a lesser extent, rolling of the rearmost cup seal in the master cylinder."

This is why Ford now recommends changing brake fluid every 3 years. As brake fluid is hygroscopic, it absorbs moisture, which over time results in damage to brake hydraulic components.

Also saw some issues on the interwebs regarding Canadian EcoBoost 3.5 F-150s having an issue with condensation contamination of the brake vacuum pump - related - who knows?

Unrelated. 2011-2012 3.5 GTDI models used an electronic vacuum pump mounted behind the driver's side headlight to provide vacuum during a cold start. Because of it's location it was susceptible to corrosion, which could cause it fail. This can result in a hard brake pedal (low power assist) only during a cold start. Even under those conditions, the ABS Module will sense the low vacuum and run the HCU to provide hydraulic assist.

 

[7GenTex]

This is why Ford now recommends changing brake fluid every 3 years. As brake fluid is hygroscopic, it absorbs moisture, which over time results in damage to brake hydraulic components.

No, apparently not caused by contaminated fluid...............


It seems the problem may be the single cup Hitachi master cylinder which has a single seal in the bore, versus dual seals attached to the piston.

"Ford F-150 built between the years of 2013-2018 are equipped with master cylinders supplied by Hitachi. Ford previously used master cylinders manufactured by Bosch.


The Hitachi master cylinders have pistons fitted with a single cup seal responsible for containing pressurized brake fluid. Normally master cylinders are usually fitted with two cup seals to ensure that fluid does not leak out of the master cylinders. When master cylinders lose their brake fluid, front brakes can suddenly fail. This may cause the vehicle to fail to stop, or rolling through stops signs, and even roll into objects.


According to a lawsuit that was recently filed, pistons fitted with a single cup seal is unusual. Pistons in master cylinders are normally made with two cup seals thus ensuring that fluid does not leak out of the master cylinders. https://www.carcomplaints.com/news/2018/ford-f-150-master-cylinder-problems-lawsuit.shtml Master cylinders made by Hitachi supposedly place twice the sealing loads on its single piston cup seals. Plaintiffs in the lawsuit claim the design moves the usual placement of the cup seal from the piston to the master cylinder’s bore where the single cup seal rests in a groove made into the bore of the master cylinder.

The plaintiffs also allege this defect involves failure of the piston cup seals. The seals roll and become removed from their grooves and losing the seal. That allows pressurized brake fluid to escape from the master cylinder and back toward the brake booster."


https://www.carcomplaints.com/news/2018/ford-f-150-master-cylinder-problems-lawsuit.shtml

 

[FordTechOne]

No, apparently not caused by contaminated fluid...............


It seems the problem is the single cup Hitachi master cylinder which has a single seal in the bore, versus attached to the piston.

"Ford F-150 built between the years of 2013-2018 are equipped with master cylinders supplied by Hitachi. Ford previously used master cylinders manufactured by Bosch.


The Hitachi master cylinders have pistons fitted with a single cup seal responsible for containing pressurized brake fluid. Normally master cylinders are usually fitted with two cup seals to ensure that fluid does not leak out of the master cylinders. When master cylinders lose their brake fluid, front brakes can suddenly fail. This may cause the vehicle to fail to stop, or rolling through stops signs, and even roll into objects.


According to a lawsuit that was recently filed, pistons fitted with a single cup seal is unusual. Pistons in master cylinders are normally made with two cup seals thus ensuring that fluid does not leak out of the master cylinders. https://www.carcomplaints.com/news/2018/ford-f-150-master-cylinder-problems-lawsuit.shtml Master cylinders made by Hitachi supposedly place twice the sealing loads on its single piston cup seals. Plaintiffs in the lawsuit claim the design moves the usual placement of the cup seal from the piston to the master cylinder’s bore where the single cup seal rests in a groove made into the bore of the master cylinder.

The plaintiffs also allege this defect involves failure of the piston cup seals. The seals roll and become removed from their grooves and losing the seal. That allows pressurized brake fluid to escape from the master cylinder and back toward the brake booster."


https://www.carcomplaints.com/news/2018/ford-f-150-master-cylinder-problems-lawsuit.shtml

Interesting information. Clearly they should have stayed with Bosch, which is one of the highest rated Tier 1 suppliers globally. Hitachi is japanese garbage, just like the Yazaki BJBs with the melted F27 on Gen 1's and the garbage Mitsubishi starter that left me stranded in my Grand Cherokee. FCA has also had well documented bearing failures in IHI (Japanese) superchargers on their 6.2 S/C, they should have went with Eaton, which is the benchmark in superchargers.

 

[7GenTex]

Well, ready to go...........pretty quick compared to the "back-ordered - no ETA" initial report for the booster.

Replaced the master cylinder and the brake booster. Bled the brakes.

I'll pick it up tomorrow.


EDIT - picked it up - all good so far.

Pedal feels better than it did on day 1...................

 

[7GenTex]

Late update.............about 3 months after the "fix" above.

Dealer seems to have forgot to tighten up the brake lines at the master cylinder...........
Had brake fluid squirting all over the place.

Fun & games

All seems good now, though the soft pedal as compared to my other (numerous) F-150's continues.......

 

[Shady 04]

Recall #22S11, Just received via FordPass, Brake Master Cylinder Leak into Booster. Called my service department and they had to look it up only to find out that the memo to owners isn't scheduled to be sent out until 18 Apr 22. Replacement parts to follow that. Talk about bass-ackwards. Seems like I was the 1st person to tell them about the recall. Take a seat and remain quiet until I call on you! So much for leaning forward.

 

[RaptizedBK]

Following. Someone sent me a text about this issue today. I have a 2018. Nothing in FordPass yet.

 

[BenBB]

Got a postcard today, class action lawsuit for "2013-2018 F150 Hitachi step-bore master cylinder that was not part of a recall Ford issued in 2020". According to the VIN check on their website www.Fi150brakelitigation.com mine's one of 'em...

 

[7GenTex]

Got a postcard today, class action lawsuit for "2013-2018 F150 Hitachi step-bore master cylinder that was not part of a recall Ford issued in 2020". According to the VIN check on their website www.Fi150brakelitigation.com mine's one of 'em...

Ditto...........