I have been driving this year with a flaky starter solenoid. It takes a few times to engage the engine sometimes when starting. I ruled out the key switch by shorting the screws on the fender awhile back.

I ordered a new Bosch Solenoid (part # 31035). I have a SR70X Bosch starter with the solenoid on the bottom cause of the trap. I pulled the solenoid today and had to drill out the screw heads since they were stuck and stripped. I got some new screws M5x.8 45mm long and installed the new solenoid. When I got it back in I turned the key and just got a click on the relay on the drivers fender and also could feel the starter solenoid click but not engaging of the engine or spinning. I tried it a few times with the same result. Pulled the starter again and put the old solenoid back on the starter. I put the starter back in with the same result I have been having for the past year. It clicks and then spins sometimes before engaging the engine and starting.

It seems like the solenoid is engaging but not pulling the piece back to push the ring gear out that turns the flywheel. What should I check next? What caused the flaky solenoid? I clean my old solenoid inside with steel wool and lightly oiled it and it didn't seem to help at all.

Any suggestions?

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85 300D Turbo