Hydroboost brakes

[waren]

Wondering what everyone is using for a 12V vacuum pump after the hydroboost conversion? I assume vacuum is still needed for other functions.

The photos showing the vacuum and hydroboost master cylinders were very helpful in understanding why Erik machined a spacer. Great info all around.

[desertsherpa]

The F250's and and F350's of that area have an electric vacuum pump that runs on 12v.
I got a cheap dorman replacement to solve this problem.
I wired my up next to the degas bottle and intake, and mounted it to the fender well. It comes w/ rubber isolating mounts, and a pigtail. I wired it to run.

I then deleted the original vacuum manifold/distro block, and have one vacuum line that runs from my air-box and connects to the vacuum line that comes across the cowl and enters near the heater core.

Those vacuum pumps will shut off if they pull enough vacuum. Mine never does, its annoying until the 6.0 fires up. LOL

I'm not super happy w/ the vacuum supplied, but the noise is not in the cab, and eventually MAX AC air come from the vents. I think I need to go test the vacuum systems. But since I've pulled the dash once, I'm living with it for now.

[waren]

Thanks for quick reply on this! Very helpful.

I suspect my belt driven vacuum pump is in early stages of failure also noisy. Based on your experience I’ll probably plug off the brake booster hose until I figure out what to do.

Erik (aka Badger) calculated and measured a ~30% increase in line pressure at equal pedal pedal pressure, however he went to the effort to keep the stock (1-1/8”) 1.125” master, using the E450 (1-5/16”) 1.3125” has 35% more area … so no increase in line pressure for equal pedal pressure. In theory, at sea level. I need to see if I can find a 1.125” master designed for hydroboost.

Edit: cardone 133110 appears to be designed for hydroboost and lists a 1.125” bore.

2C2Z2140CA, 3C2Z2140EA, 6C2Z2140EA

Bore Diameter N:
1-1/8"
Color:
Gray
Material:
Aluminum
Mounting Hole Quantity:
2
Other Port Size:
3/8"-24
Port Quantity:
2
Primary Port Size:
7/16"-24
Reservoir Included:
No
Secondary Port Size:
9/16"-18

[desertsherpa]

I would be careful. The master cylinders are not like legos and don't match up on my 2009. I had to buy a new pedal, master and booster. I did that several times.

I'm not even sure what bore size I have now. I know that : I have hydroboost, and the abs fittings are metric, and all my parts are e450. The need for a new pedal really blindsided me.

[desertsherpa]

Originally Posted by desertsherpa

Ok Update,
After working through many things. I have very effective brakes.
Infact, too effective.

Current set up is e-450 hydroboost brakes, motocraft parts from rockauto.
And I had to move the post on the brake pedal up to account for different brake pedal geometry.

I did have an issue where the brakes were way to over- reactive, and I fixed this by buying the right return hose assembly that moves the hydro boost return line closer to the pump, reducing back pressure from the power steering assembly.

Now my issue is the first 1" of brake pedal travel does not return. Does anyone out there have any tips on diagnosing this?? I'm pretty sure its on the hydroboost side, as I've been bleeding the brakes w/ a power bleeder, alot.

I guess I should resolve this issue for future people.
Read this post knowing I have a 2009 E350. Which is an odd year. 2nd to last year of the diesels, and first year of the updated interior and electronics.

I had three issues I had to debug. First was I got a bad "new" master cylinder. I replaced it w/ a motorcraft and it now works.

The second issue that I had was I re-plumbed the return from the power steering pump and hydroboost to both return to near the same return as the brakes. This caused power steering return to back pressure the hydroboost return.

Sooo... The e450 specific 6.0 power steering reservoir to pump line has a place to tie in one of the returns (check the diagram, I think its the hydro-boost) that us much closer to the pump, and away from the reservoir. This "relieves" some of the back pressure on the brakes and allows them to return.

Third issue I had was I was trying to get all this to work with a 2009 vacuum pump brake pedal assembly. So I bought two NEW brake pedal assemblies from a ford parts website, and looked at them (vs the one I had that I had franken cobbled and hacked on). The hydroboost pedal has the attachment post mounted in a significantly higher on the pedal.

[desertsherpa]

Originally Posted by waren

Thanks for quick reply on this! Very helpful.

I suspect my belt driven vacuum pump is in early stages of failure also noisy. Based on your experience I’ll probably plug off the brake booster hose until I figure out what to do.

Erik (aka Badger) calculated and measured a ~30% increase in line pressure at equal pedal pedal pressure, however he went to the effort to keep the stock (1-1/8”) 1.125” master, using the E450 (1-5/16”) 1.3125” has 35% more area … so no increase in line pressure for equal pedal pressure. In theory, at sea level. I need to see if I can find a 1.125” master designed for hydroboost.

Edit: cardone 133110 appears to be designed for hydroboost and lists a 1.125” bore.

2C2Z2140CA, 3C2Z2140EA, 6C2Z2140EA

Bore Diameter N:
1-1/8"
Color:
Gray
Material:
Aluminum
Mounting Hole Quantity:
2
Other Port Size:
3/8"-24
Port Quantity:
2
Primary Port Size:
7/16"-24
Reservoir Included:
No
Secondary Port Size:
9/16"-18

I would order all of them, and plan a return.
You are talking fractional sizes here, of which there is more info on the forums for those years (pre 2008/9)

[waren]

I have a 2006 6L, so hopefully I won’t have the brake pedal issues you ran into.

No question even with the part numbers other members have posted here getting the correct parts especially the hoses is going to be a challenge, with several installing custom lines in the end.

The warning on the master cylinder is fair, it seems like 3/16” in diameter would be negligible, but it’s a 35% increase in area which almost perfectly offsets the increased line pressure of the hydroboost. This makes sense I doubt ford intended to significantly raise the line pressure to pedal pressure ratio, just provide more consistent and reliable pressure.

Erik kept the MC diameter at 1.125” and measured an increase of ~30% line pressure … which I believe he said was noticeable off-road, less so on road. With the larger E450 MC on paper there would be very little increase in performance, assuming the vacuum pump and booster are in good working order.

Lots of inconsistency in MC bore size between E350 and E450 1-1/8” and 1-5/16” shown for both, and of course motor craft doesn’t publish bore size for BRMC30 / 29. Pretty low confidence in the cardone spec accuracy. It’s possible the only difference between BRMC30 / 29 is the length of the snout.

[waren]

https://fordbbas.com/publications

These only go back to 2014 now. In 2014 vacuum MC was 1-5/16 and hydroboost MC was 1-3/8.

Vacuum ratio is 7.5:1
Hydroboost is 6.76:1

One of the posts above mentioned an increase in calliper piston size around the facelift timeframe and larger MC as well which makes sense.

[desertsherpa]

I'm running super duty axles front and rear, and the brakes appropriate for those axles.

On the rear axle, I have a 2010 Sterling 10.5 FF Elocker from a F250
That 2010 Sterling was set up for 2 rear brake lines from the ABS unit.
My 2009 NON-RSC Diesel has one brake line for the rear. (O Joy).

Therefore, from the frame at the rear, I have a brake fitting adapter, then an extended soft brake line for a lifted truck down to a tee on the axle.

That extended brake line is a Rough Country SKU: 89713
Ford Extended Rear Brake Line | 4-8in Lifts (99-04 F250/350)

Then on the axle I have the circa (bad memory) 1994-2004 Sterling Axle rear brake lines from the junk yard.

[waren]

That’s a nice setup.

I’m hoping to install a 2002 ish sterling, convert to 8x6.5”, then install a factory elocker. It’s currently a SF dana in the rear. I think I can install the E350 rear calipers, rotors and ebrake on the 1st gen Superduty sterling which is the plan.

My front is a IFS d44 with d50 knuckles. It was built like that not by me. The ring gear is D44 so she’s no rock crawler but the load components (ball joints, bearings) are D50. I’m close to the front axle load rating with the diesel and partial camper build but not at it, and it has been reliable for my use in the 6 years I’ve owned it, so no plans to change to a solid axle, so far. The ‘96 F350 front caliper on there have the same piston diameter of the ‘06 E350 front caliper. I believe Upgrade options are limited. This is why I’m pretty bent on keeping the MC 1.125”.