Thanks for the tip.

I had been using a manual impact driver with a 3 lb sledge but hadn't thought to add heat. It turns out the heat worked great and I was able to remove the remaining screws.

Luckily, after I removed the front cover and diaphragm I was able to remove the broken screws using a pair of vise grips on the shaft of the screws.

The diaphragm appears to be in good shape with no holes or tears.

I plan on replacing all of the flat headed screws on the top cover with some socket headed cap screws to make things easier if I ever have to dig into this thing again.

Now I'm just waiting for the rebuild kit to arrive.

Thanks again for your help.

I was able to get the vacuum pump rebuilt and back on the car today.

As suggested I finally performed a compression test. Results looked good with all cylinders above 360 psi.

The next step will be checking the timing on the injection pump but I have a question.

Is it important to determine cam chain stretch before trying to time the injection pump?

When your Fuel Injection Pump is re-timed you are timing it to the degress on the Crankshaft so that corrects any Timing Chain Stretch/Gear Wear issues for the Fuel Injection Pump but does not correct any Camshaft Timing issues (that could be corrected with an offset Woodruff Key or a new Timing Chain).

You can get an idea of the Camshaft Timing by extremely exactly lining up the Camshaft Gear Timing Mark with the Timing Mark on the Front Camshaft Bearing Tower and looking at what degrees that pointer points to.

Of course it would be nice to correct the Camshaft Timing first end then do the Fuel Injection Pump Timing.

The above info applies to the 616 and 617 Engines so you should look up the info on your specific Engine to be sure.

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84 300D, 82 Volvo 244Gl Diesel

Thanks for the explanation.

I checked the cam timing this morning and it looks like there is about 5 degrees of chain stretch.

Is there anyway to see if there is an offset woodruff key installed without removing the cam sprocket?

Still trying to track down this smoking issue but I made a discovery this morning that will change my next move for sure.

After performing a diesel purge, I replaced both fuel filters and started the car. As the car idled I cracked each injector line to make sure there was no air in the system. When I got to cylinder 4, the engine did not sputter when I unscrewed the line slightly nor did I see fuel. I continued to unscrew the line until it was completely removed and still, no fuel.

No wonder this car is hard to start.

So what's next, replace the injection pump?

Thought I should chime in and share the ending to my injection pump issue.

It turned out to be a stuck plunger that refused to stay unstuck. I pulled the injection pump from my parts car but it was in pretty rough shape too so I had to track down another option. Luckily, I found a rebuilt pump for a fair price locally and was able to install it today.

Now the car runs like a top and I'm very happy with it.

Believe everything you read about that lower injection pump bolt. It's a tricky one but I was finally able to get to it using a cheap 13mm obstruction wrench.

Thanks for all your help.

Would you mind sharing where you found the rebuilt pump?

Thanks.