From cba@atl.hp.com Wed Oct 5 05:44 PDT 1994 Received: from mailer by fshpp1 with SMTP (16.8/16.2) id AA25284; Wed, 5 Oct 94 05:44:53 -0700 Return-Path: Received: from hp.com by UG.EDS.COM (PMDF V4.2-11 #4) id <01HHWN4454A80002BL@UG.EDS.COM>; Wed, 5 Oct 1994 05:43:42 PDT Received: from i3109e.atl.hp.com (s3109e6.atl.hp.com) by hp.com with SMTP (1.37.109.11/15.5+ECS 3.3) id AA120350981; Wed, 5 Oct 1994 05:43:01 -0700 Received: by i3109e.atl.hp.com (1.37.109.8/15.5+ECS 3.3) id AA20888; Wed, 5 Oct 1994 08:42:49 -0400 Date: Wed, 05 Oct 1994 08:42:48 -0400 (EDT) From: Brian Abernathy Subject: Re: Rebuilding 914 ign switch. (fwd) To: jan@UG.EDS.COM Message-Id: <9410051242.AA20888@i3109e.atl.hp.com> X-Envelope-To: JAN@FSHPP1 Content-Transfer-Encoding: 7BIT Mailer: Elm [revision: 70.85] Status: RO Sure. Here it is, in it's entirety. > > > Brian, and my Porschephile friends; > Yes, the switch can be cleaned and reused. > Procedure: > Use an X/acto knife blade to gently pry the 2 tabs on the side > of the switch body apart to separate the contacts from the cover. > Be careful not to flex the nylon too far or the tabs will break. > Use a solvent to clean the center and outer contacts on both > halves of the switch. You may have to use a pencil eraser to scrub > the oxides off the contact zone, an ink eraser works best. > Re-lube with silicone grease and reassemble. > End procedure. > > The switch body is keyed so you cannot mess it up. The center contact > is silver plated and is the starter contact. While you have it apart > inspect carefully for heat warpage that might cause mis-alignment of > the internals and aggravate the fail mode. > > I've posted this before about the cause of this failure: > There is no spike supressor diode across the starter's engagement > solenoid. The ~300V spike is enough to fritz the contacts over time. > Adding a 1n4004 or 4005 in proper polarity will permanent fix. > > Not sure, but all 9xx cars may share in this.. > > -kyle > Let me add a couple of comments: First, if you have not pulled it out of your steering column yet, remember that there is an interlock, which prevents the steering wheel from being moved when the switch is in the "off" position. Second, once you have the entire sleeve out, there is a small screw in the cylinder body. That screw is all that is holding the switch in place. I found that a screwdriver that was designed for eyeglass repair is the perfect size. Third: He mentioned x-acto knives. I used two small flat-blade screwdrivers. There are two places where the switch could actually come apart. The first one is near the top of the switch, but it is not the one you want. The actual place is closer to the middle. I found that if I put one small screwdriver under one tab, then slowly working the other one around the second tab would do the trick. Fourth: Hold the switch upright, with the plug facing down. There are several SMALL parts, including three springs, which will probably want to vacate their confinement. Last: The contacts in mine were not oxidized, but they were badly pitted. I took a piece of emory cloth about 1/4 inch wide, and wrapped it over the end of my finger. Then, I carefully polished the contacts. Emory cloth can leave a conductive residue, so be careful. Hope that helps. I hope to get my '74 914 working while this fall weather is still here. -- ______________________________________________________________________________ Humanoid creatures who abide in a | Brian Abernathy vitreous structure should never | Hewlett-Packard Company attempt to apply kinetic force to | Atlanta Response Center a petrous formation. | Internet: cba@atl.hp.com | CIS: 70223,167 ______________________________________________________________________________