I have a 1980 300SD with about 290K miles. I change oil and filters and do little else to the car. Recently the engine started making a new ticking noise. Before I identified the source, the ticking disappeared. Simultaneously, I lost all vacuum. I looked at the vacuum pump on the front of the engine and see that it has self-destructed. The case is cracked, with pieces missing. What is involved in replacing this pump? Is there another underlying problem that has caused the pump failure? Thanks.[/align]

 

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FI, thanks for the reply - good advice.

After removal, it's apparent that the 2 8mm 8.8 grade bolts holding the cam plate to the timing chain sprocket backed out.One of these then slammed into the guts of the pump. The head was battered and bent at a 30 degree angle. The piston connecting rod, roller assembly, and half of the rocker arm were gone. The large spring was distorted and pushing directly against the cam plate, galling it.The aft (lower) spring retainer was fused to the spring. It looks likethe offending bolt head swept the pump parts around to the 7 o'clock position, where they were punched through the case of the pump.Some (but not all) debris was found on and around the tach sensor and AC compressor. I figure I’ve left the rest on the road. Timing chain sprocket and damper are in good shape. I have not dropped the pan. There was no evidence that any debris entered the timing chain cavity. Top end of the pump – valves and piston (except for conn rod) are in good shape. I have run the engine with no further trouble.

I need a new pump and probably a new cam plate. And a couple of new 8mm bolts!

EOM - finally. Jim