2005 E350 6.0 PS, hard pedal. Vacuum at check valve is 19 in hg, no sound. Put check valve back in booster, hardly any vacuum, sounds like I'm making popcorn! Vacuum is over 20 directly in the pump tube. Which is to be replaced, the pump or the booster, or both? Find it hard to believe both would go out together. No fluid is in the lines. Just quit.

 

Man, the E series is a booger on the brake stuff! Our F series uses the hydroboost so it may take a while to get a good response. One member here has added a vac pump and resivour so he has a back-up if the main system fails. Here's a bump anyway

 

Get one of the OEM/Liquid siphoning vacuum pump kit (25136) | Vacuum Pump Brake Bleed Kit | AutoZone.com
at Autozone. It's a vacuum pump kit and then put an adaptor on it so you can put the
booster under a vacuum and see if it is leaking. Also check the grommet on the booster
and see if it is getting brittle and that can also be a leak point. Last thing to check
under the master cylinder is the pushrod seals. The booster should hold a vacuum
for a short time.You can also put the hand pump in the line to the engine pump
with the check valve removed and see if it will hold a vacuum. Last see if the
check valve is leaking.
Let us know how this all goes.

Sean

 

Failed vacuum pump. The part number from Ford is 4C2Z-2A451-AA. You will need a power steering pump pulley puller/installer to replace this part. A 10mm flexible head Gearwrench will be your best friend for this job.

 

How come when the booster is hooked up I have no vacuum, but if I have the vacuum guage on the check valve I get a reading? Just to low of a vacuum? I appreciate the response, trust me!

 

I'd be a rich man if I were to have gotten a dollar for each one of these I have replaced on an E-350 for the exact concern you describe. Notice I say E-350 and not E-450. And that's because on E-450 applications a hydroboost is used for brake assist, while the vacuum pump is dedicated exclusively to providing vacuum to control the mode selection for the HVAC, therefore much less demand on the pump.

 

Thanks for the input, will put the pump in tomorrow. So don't worry about the booster while I have the stuff out of the way? Do you test the vacuum on the open spot on the manifold where the lines all hook up, and what should I have for vacuum?

 

Well, installed a new vacuum pump.What a pain in the butt! Didn't know my old body could still bend in that many directions. But I still have hard pedal. Looks like it was my booster. Will post in an hour or so after I replace the booster. That's the way it goes!

 

This was helpful in hind-sight! But by the sound of the pump, it was probably going. New one sounds much better, or should I say no sound. That's my story and I'm sticking to it!!