[jamie hopcia]

I have a 2002 E350 Super Duty 7.3 PSD, and have a recurring problem with vacuum pumps. I am now on my fourth pump in a year and a half. I have checked all related components, brake booster, master cylinder, pads, discs, and can find no other problems in the system. Can the pumps be overworked? It seems that they work continuously anyway but I don"t know. Another, probably related problem, is a brake warning light that goes on and off for reasons I can't figure. Any help would be greatly appreciated, thank you.

PS. I know that the brake light goes on when vacuum gets low, but it also goes on when the vacuum is fine and a new pump has been installed.

 

[klhansen]

The vacuum pump on 7.3L's has nothing to do with the brakes. It's a small electric pump that supplies vacuum to the HVAC controls and the auto locking hubs.

The brake booster is hydraulically powered by the Power Steering pump.

You need to be a bit more specific on your problem in order to get help.

 

[jamie hopcia]

My 2002 turbo diesel van uses the vacuum pump to power the brake booster, and the climate control doors. And it is a 7.3.

 

[klhansen]

My mistake. All the pickups with 7.3's have the hydroboost.

Vans can have either hydroboost or vacuum booster.

Here's a blurb from the Service Manual. Maybe that will help.

Brake Booster

1. With the engine OFF, apply the brake pedal several times to deplete the power assist reserve in the brake booster.

1. Hold the brake pedal in the applied position.

1. Start the engine.

1. The brake pedal should drop slightly after the engine starts.

1. On vacuum brake booster equipped vehicles, if the brake pedal does not drop after the engine is started, check for vacuum at the brake booster.
   • With the engine OFF, disconnect the vacuum hose and check valve at the brake booster.
   • Vacuum should be heard escaping from the brake booster.

1. If vacuum is not available at the brake booster, check for vacuum at the source and check the vacuum hose for leaks.
   • On vehicles without a vacuum pump, check for vacuum at the engine. For additional information, refer to Section 303-00 .
   • On vacuum pump equipped vehicles, inspect the accessory drive and accessory drive belt. For additional information, refer to Section 303-05 .

1. If vacuum is available at the brake booster and no power assist is felt, install a new brake booster and retest the system. For additional information, refer to Section 206-07 .

1. On Hydro-Boost® equipped vehicles, if the brake pedal does not drop after the engine is started, check the power steering pump pressure and flow. For additional information, refer to Section 211-00 .

1. If power steering pump pressure is available to the Hydro-Boost® and no power assist is felt, install a new Hydro-Boost® brake booster and retest the system. For additional information, refer to Section 206-07 .

I'll move your thread over to the Van forum. Those guys will have more experience with this and will probably be able to help.

Welcome to TheDieselStop

 

[jamie hopcia]

Thanks, klhansen

 

[johnhenrykc]

The vacuum pump on 7.3L's has nothing to do with the brakes. It's a small electric pump that supplies vacuum to the HVAC controls and the auto locking hubs. The brake booster is hydraulically powered by the Power Steering pump. You need to be a bit more specific on your problem in order to get help.

Uh, you must not be familiar with the 7.3 motor because the vacuum pump most definitely has to do with the brakes (pre 1999). You ought to know what you're talking about before sounding so dismissive. See how that works ?

 

[johnhenrykc]

The vacuum pump on 7.3L's has nothing to do with the brakes. It's a small electric pump that supplies vacuum to the HVAC controls and the auto locking hubs.

The brake booster is hydraulically powered by the Power Steering pump.

You need to be a bit more specific on your problem in order to get help.

This guy doesn't know the 7.3

 

[bugman]

This guy doesn't know the 7.3

Before you respond to a 11+ year old thread for a 99+ year of truck, you may want to do some homework.

While the vacuum pump does work with the brakes on a 94-97 year of truck, it has nothing to do with a 99+ year of truck.

Sent from my SM-A426U using Tapatalk

 

[klhansen]

@johnhenrykc
Also, you didn't read my followup post acknowledging that the 99+ vans use a belt driven vacuum pump. The 99+ pickups use a hydroboost and a tiny electric pump for HVAC and hubs.

You're welcome to contribute here, but please educate yourself (as in read the whole thread) before weighing in.

And do NOT attack other members. That will earn you an account ban, either temporary or permanent.

 

[Big Horn]

Klhansen - very diplomatically handled, my hat’s off to you.