a) On an 84 300DT vacuum pump, is it a single or a double diaphragm?

b) Do you require a special tool to replace the diaphragm?

There's evidence of oil in the line which suggests a possible broken vacuum pump diaphragm.

Thanks for your help.

An 84 should have a piston type pump that vents into the crankcase. If you have oil in the main vac line, it isn't from the pump, usually, more likely to be from a leaking vacuum shutoff on the IP.

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

Peter,

Can you r & r the vacuum control valve without removing the IP?

Thanks.

Yes, but you MUST be prepared for a engine run-away on restart -- if the linkage gets screwed up while replacing the shutoff, it can cause the fuel control rack to fall full open.

Larry Bible, I think, had this happen, blew the engine up.

Otherwise, do a search, it's not very difficult to do. Verify that it is bad, first -- any oil in the line going to the shutoff means it's leaking. Will also have slow or no shutoff.

If someone else replace it and didn't clean the lines, you will need to flush the vac lines with brake parts cleaner and replace any softened rubber parts.

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

I am not sure how you can pull it out with the oil filter canister so close?

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