You cant get 13.6 V at the battery with a dead alt. Bosch alts dont like having the battery removed when they are running. Its a good way to toast the regulator. I can speak with experience on that. Dont do it on any car. What is the real problem? If you have a problem with the voltage dropping back to say 12 V when you turn the head lights etc on with the engine revving over 1000rpm. The first thing I would look at is the lead from the alt to the battery, If you can take the back off the plug on the alt, you could test the alt output voltage, should be approx 13.6v. If a lot less, check the alt brushes. If they are good, then the alt needs looking at further.

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Grumpy Old Diesel Owners Club group

I no longer question authority, I annoy authority. More effect, less effort....

1967 230-6 auto parts car. rust bucket.
1980 300D now parts car 800k miles
1984 300D 500k miles
1987 250td 160k miles English import
2001 jeep turbo diesel 130k miles
1998 jeep tdi ~ followed me home. Needs a turbo.
1968 Ford F750 truck. 6-354 diesel conversion.
Other toys ~J.D.,Cat & GM ~ mainly earth moving