I may be looking at the problem differently; but, even with an Electric Vacuum pump he will need to remove the defective one from his Engine before parts of it fall into the Timing Chain and causes some serious damage to his Engine.

At the very least he would have to pull the pump off and take out the parts that could fall into the Engine and put it back on or have some sort of plate made to cover the hole.

There would be 2 loss of vacuum problems. No Power Brakes and No Vacuum to soften the shifting of an Automatic transmission; also he would have to lift the Hood and apply the Manual Shutoff to shut off the Engine.

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84 300D, 82 Volvo 244Gl Diesel