Delco (black distributor cap) or Bosch (brown distributor cap)
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How often should I replace rotor arm and cap

Post by will broad » Fri Feb 09, 2018 7:21 pm
Joined: Mon May 30, 2016 4:29 pm
Posts: 19
As the subject says, as I have not replaced my distributor cap and rotor arm for a few years now

Re: How often should I replace rotor arm and cap

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Post by Phil Bradshaw » Club admin » Fri Feb 09, 2018 8:43 pm
Joined: Sun Sep 02, 2012 7:15 pm
Posts: 3371
As necessary. Neither are service items for regular replacement like contact breaker points (but still need to be checked).

Delco D300 contact breaker distributor (black cap): replace rotor when central contact loses its springiness, cap when carbon button in the top works loose.

Bosch JHFU4 electronic distributor (brown cap): replace rotor arm when internal resistor fails, cap when carbon button is worn down or its spring has deteriorated.

Both: replace when contacts in cap or on rotor are past cleaning back to bright metal; replace cap and HT leads if terminals become corroded.
  • What is real is not the external form but the idea, the essence of things. Constantin Brâncuși

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