Engine, HVAC

6.9 / 7.3 IDI Vacuum Pump Bracket Hole Enhancement, to Fix Hose Clash

One of the design flaws of the vacuum pump bracket on the 6.9 or 7.3 IDI E-series van, is the location of one of the crucial mounting bolt holes.  Due to the design of the vacuum pump and the design of the bracket, there is a slight clash with the bolt and hose.  This clash causes rubbing on the hose, and can lead to vacuum hose failure.  When the vacuum hose fails, the vac system increases in pressure, eventually disabling power brake assist, climate control, and some transmission shifting issues.

This modification allows for the pump hose and bracket bolt to separate completely.

On the E-series vans (and RV’s, etc), the vacuum pump is located on the passenger side of the engine front.  It mounts to the cylinder head with three 3/8″ diameter mounting bolts.

The vacuum supply hose drapes down from the engine bay ceiling and connects to the top of the vacuum pump.

The pump has an inlet on top that allows for the hose to connect with a clamp.  That is precisely where the problem lies.  That mounting bolt rubs on the hose, thus over time, ruining its ability to hold vacuum pressure.

Here is the location of the bracket hole that is causing all this trouble:

One way to fix this is to run a countersunk bolt in there.  I didn’t want to bore out a 45 deg countersink in that bracket.  So instead, I used a Dremel to grind out about 3/16″-1/4″ of material in that bolt hole.

There is still plenty of meat to that bracket, so it shouldn’t affect the structural integrity of the bracket.  By deepening the hole, the bolt sits inside the hole, and avoids the hose all together.

Once ground down, I sanded the whole bracket and gave it a new coat of high-temp paint:

I reinstalled the bracket on the cylinder head to see how it fits.  Thankfully, the deepening of the hole didn’t require me to get a shorter bolt.  You may need to chase your threads prior to installing this modified bracket.

That’s about it.  Reinstall the vacuum pump and it shouldn’t clash with the hose anymore.

 

 

 

 

No warranty. You are responsible for your vehicle. For novelty use only. Not responsible for anything or anyone. Not responsible for damage to your vehicle, you, or anyone or anything.

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