Oil pump failure(probable cause ?)

[iamchappy]

I had the intermediate shaft on my 79 3.0 sc engine break at the circlip splined shaft today at the front of the engine, What could of caused the pump to seize like that, I had driven the car very easy for about 30 minutes stopped at a friends, the car sat maybe another 20 minutes and it failed driving 2 blocks home, When I reached my driveway the oil pressure was gone and sounds of a bad rod knock present. Examination of the drain plug and sump screen showed nothing abnormal?.

[Jim Sims]

Have you already taken the engine apart!?

The first thing that comes to mind is that it ingested a bit of debris that jammed it abruptly; shock loading broke the shaft.

The second possibility is one of the layshaft bearings was bad/starved for oil (plugged oil passageway?) and seized.

Finally, the layshaft could have simply reached the end of it's fatigue life; how many miles are on the engine?

Good luck. Jim

[iamchappy]

No the engine is still in the car, the engine was rebuilt about 50,000 miles ago and runs very smooth and strong outside of the pump failure, the engine runs great, I think there are around 156,000 on the engines life the rebuild took place at 106,000.
I cant imagine how it could ingest any debris. how small a particle would it take to seize a pump.

[KlaasyT]

I had the same failure on my 72t. A tooth broke in the pump shearing the layshaft at the circlip. This car had been sitting about 15 years and it was an initial attempt to bring it back to life.
I couldn't find any debris other than the tooth.I'm thinking it was fatigue in my case. Needless to say every thing came apart.