Power Brake Vacuum Assist Failure on Diesel Vehicles - Page 7

**Gooseberry** · 01-30-2019, 06:06 PM

Quote:

Originally Posted by HK33FAN

Time to add Sportacus to the list of mechanical vacuum pump failers. Here are the stats, 2007 6.0, 75k miles. in retrospect, I should have noticed it going out a few months ago. It all started when the vents would not change from defrost to floor vents, causing very cold toes. for quite a few months I have been hearing a puttering sound on the driver side and thought it was an exhaust manifold leak. three days ago it started to sound like a small air compressor then holy S$%#$$ no breaks, well very little braking. 10000lb without brake assist was not easy to stop in freeway traffic. I am surprised there is no safety recall on this issue, this could have been deadly. welp, It's in the shop now, so stand by for updates on price and shop quality report. AAA towed it without to much fuss, tow company wanted to confirm that is was under 12,000lb.

Other members have asked about electric pump backup options. Ford did use electric vacuum pumps on the F250s and E250s, Dorman part number #904-214. I will be buying one and adding it to my spare parts kit, It will be much easier to splice in an electric pump then try to install a mechanical one in the field.

Good idea on the pump but you might want to make sure you have it pre wired and have the vacuum line with adapters to make it work. Seems like it has smaller lines and might need a vacuum bottle to keep vacuum.

HK33FAN · 01-30-2019, 10:58 PM

Quote:

Originally Posted by Gooseberry

Good idea on the pump but you might want to make sure you have it pre wired and have the vacuum line with adapters to make it work. Seems like it has smaller lines and might need a vacuum bottle to keep vacuum.

Great point Gooseberry,

yes, that would be the plan, pre-wire the pump and build Ts that will cut right in-line with the booster hose and small vacuum line running along the under hood wire harness. the pump has a large 3/8th(ish) outlet on one side not shown in most of the photos. These pumps were put in a lot of F250 6.0 powerstorke trucks. I am going to look at the pump first to see if it is even worth trying.

JWA · 01-31-2019, 05:37 AM

I'm curious if adding a gauge somewhere in the brake system's vacuum pump would work as a warning or way to monitor the pump's operation? Would that serve as a warning to engage a back-up electric pump?

And how quickly would a back up pump restore full braking capacity?

hogasm · 01-31-2019, 09:38 AM

So what happens when the vac pump locks up and breaks the belt. You planning on the electric pump being a one time oh shit back up system?

HK33FAN · 02-05-2019, 10:28 PM

Ok so I Just picked up my van from Pro-1 Automotive here in Reno NV . $1800 got me a new vacuum pump and a new electric fan clutch that was found to be going bad. I also had a new OEM belt installed since the van has 78k on it. Everything is working good, the vacuum operated vents work now and I have good brake assist.

Prior to the vacuum pump going out, I was experiencing a slite studder at highway speed. So while the van was in the shop, I asked them to run the ford scan with IDS so they can see the Injectors with and without compensation mode on. They told me that the injectors are perfect and that during this test series they discovered the fan codes and suggested it be replaced.

Leaving on a 500-mile camp trip this weekend should be a good shakedown test.

HK33FAN · 02-05-2019, 10:47 PM

Quote:

Originally Posted by hogasm

So what happens when the vac pump locks up and breaks the belt. You planning on the electric pump being a one time oh shit back up system?

Hi Hogasm:

Have you had a mechanical vacuum pup seize up and burn off the serpentine belt? I ask because after quite a bit of research I have found that the most common failer is in the diaphragm pump or internal seals. The very few that I have heard of failing to the point of seizing, all gave the driver ample time/mileage before complete failer ensued. Please post what your experience/pump failer was, because If they commonly seize up then my electric backup pump idea would have to be re-evaluated.

The electric vacuum pump idea is just for insurance and of course, there's always a what-if scenario. we can only carry so many tools and spare parts.

graybeard · 04-02-2021, 04:37 PM

Reading this thread with interest :-)

My 2006 had a sudden catastrophic loss of vacuum. Brake pedal very hard. Standing on the pedal to get it to stop. Sure am glad I wasn't on a grade (which is rare here in CO)

Loss of vacuum presents in other ways too. For example, the solenoids for controlling your cabin ducts are vacuum based. A clue that you have no vacuum is when the defrost vents are always pushing air, regardless if you have floor, defrost or mix selected.

And then there is the sound of the vacuum pump eating itself as you are driving. The notion of have a reserve electric pump (for a F350 for example) seems a bit flawed IMO. If the vacuum pump is indeed eating itself as you drive, it won't be long before the pump comes apart and you spit the accessory belt and hopefully have cell coverage for the tow.

So, there is scant guidance on replacing a vacuum pump for this rig. The guidance from service manuals starts with remove radiator, then fan, then stator, after moving other bits around, like compressor, ..., etc. But, my understanding (albeit naive) is that the radiator need not actually be removed.

Can anybody here confirm this? I suspect some skinny tools are needed, and if I am lucky, this is a three hour job. Advice?

graybeard · 04-02-2021, 04:40 PM

By the way, this whole process (aside from pulling and pressing your vacuum pump pulley), is not fundamentally different than replacing the serpentine accessory belt, which if you are going after the pump, you probably should replace at the same time.

FWIW ...

hogasm · 04-04-2021, 06:33 PM

Quote:

Originally Posted by HK33FAN

Hi Hogasm:

Have you had a mechanical vacuum pup seize up and burn off the serpentine belt? I ask because after quite a bit of research I have found that the most common failer is in the diaphragm pump or internal seals. The very few that I have heard of failing to the point of seizing, all gave the driver ample time/mileage before complete failer ensued. Please post what your experience/pump failer was, because If they commonly seize up then my electric backup pump idea would have to be re-evaluated.

The electric vacuum pump idea is just for insurance and of course, there's always a what-if scenario. we can only carry so many tools and spare parts.

Wow how did I miss this.
I have seen a few in the shop that the belt was destroyed by a seized vac pump. One even took out the radiator. I keep a spare pump, pulley installed, along with a belt as one of the travel kit.

graybeard · 04-05-2021, 08:40 AM

By the rattle coming from the vacuum pump (while attempting to drive without vacuum boost for the brakes ...), it's coming apart internally. I would imagine this goes downhill very quickly, and if the shaft or bushings inside the pump get compromised, the shaft may seize, or it (and the pulley), under belt tension, could free itself from its rightful place and cause all sorts of problems.

@hogasm. In your experience, how nasty is a field replacement of belt &/or pump? Even getting at the tensioner looks like a complete PITA.