Rewire Ford Focus
in [Car Maintenance]
|
From: Dave Plowman (News) on 29 Jul 2007 12:34 In article <1W0ri.6334$By5.1716(a)text.news.blueyonder.co.uk>, PC Paul <urd2(a)bitrot.co.uk> wrote: > > All the pro crimp tools for RG&B pre-insulated terminals simply flatten > > the terminal - regardless of the pretty pattern they leave on the > > insulation. I'd suggest you actually examine the terminal crimp by > > removing the insulation. > > > http://www.molex.com/tnotes/crimp.html > No way can a 'flattening' crimp tool achieve a good crimp - the best you > can hope for is a crimp that you can't just pull off with your fingers... Yup. Pretty well all others produce a sort of heart shaped crimp - ie they indent the crimp to actually tighten its circumference. You need to do this to produce a gas tight seal over all of the conductor. A pre-insulated type cannot do this as it would pierce the insulation. > The other problem with the preinsulated types is that you can't see the > actual crimp - I've seen many joints where the only electrical contact > is where the connector has just about been squeezed so hard it pierces > the insulation that it's crimped onto. Yup again. I'd suggest those who think them ok cut off the insulation and examine the crimp. And compare to a properly made non insulated type. Chalk and cheese. -- *Beauty is in the eye of the beer holder * Dave Plowman dave(a)davenoise.co.uk London SW To e-mail, change noise into sound.
From: Dave Plowman (News) on 29 Jul 2007 12:39 In article <f8htgk$204$1$8300dec7(a)news.demon.co.uk>, moray <mtb_hyphen_rules(a)hotmail.co.uk> wrote: > >> Well if they make that bad a connection, then why do the big car > >> manufacturer's recommend them for wiring repairs, and use them when > >> contructing looms? > > > > The answer is they don't use them when making looms. Nor have I seen > > any of them recommend them for repairs. Looms don't usually need any > > repairs - and a maker would recommend replacement if accident damaged. > How do you think they join several wires together in wiring looms? Not with those pre-insulated types I'm talking about certainly. Why would they use a 'universal' crimp in production when it's just as cheap - or even cheaper - to use the correct one? > Manufacturer's generally recommend looms be repaired in service, due to > the uneconomical cost of replacing complete looms, although the germans > hate repaired looms, and will always advise complete replacement. Where have you seen a maker recommending those RB&Y crimps for loom repairs? -- *INDECISION is the key to FLEXIBILITY * Dave Plowman dave(a)davenoise.co.uk London SW To e-mail, change noise into sound.
From: moray on 29 Jul 2007 13:17 "Dave Plowman (News)" <dave(a)davenoise.co.uk> wrote in message news:4f0a1574c6dave(a)davenoise.co.uk... > In article <f8htgk$204$1$8300dec7(a)news.demon.co.uk>, > moray <mtb_hyphen_rules(a)hotmail.co.uk> wrote: >> >> Well if they make that bad a connection, then why do the big car >> >> manufacturer's recommend them for wiring repairs, and use them when >> >> contructing looms? >> > >> > The answer is they don't use them when making looms. Nor have I seen >> > any of them recommend them for repairs. Looms don't usually need any >> > repairs - and a maker would recommend replacement if accident damaged. > >> How do you think they join several wires together in wiring looms? > > Not with those pre-insulated types I'm talking about certainly. Why would > they use a 'universal' crimp in production when it's just as cheap - or > even cheaper - to use the correct one? > >> Manufacturer's generally recommend looms be repaired in service, due to >> the uneconomical cost of replacing complete looms, although the germans >> hate repaired looms, and will always advise complete replacement. > > Where have you seen a maker recommending those RB&Y crimps for loom > repairs? Most common ones I deal with are the ones that come with replacement advance solenoids for Bosch VP pumps, plus I've seen them mentioned in official loom repair guides. Manufacturers spec a watertight and mechanically sound repair, which heatshrink butts meet. Plus they offer the advantages of being quicker to fit, and being able to fit them in more inaccesible places than you can solder. Manufacturer's certainly don't advise adding in extra connectors.
From: Malc on 29 Jul 2007 16:44 Guy King wrote: > The message <rcYqi.6170$By5.6081(a)text.news.blueyonder.co.uk> > from "Malc" <malwhite(a)blueyonder.co.uk> contains these words: > >> When I worked for Westland Aerospace the components like resistors >> and diodes on PCBs would have loops formed in the legs to help with >> strain relief. > > I always through those little wiggles were to space the component off > the board rather than sit hard down on the surface. That's certainly > why I used to do it if I had a resistor I knew was going to get > warmer than I'd like. These were a complete 360 degree loop. Probably a combination of vibration resistance and heat dissipation although, as I said they were potted as well. In a compound called X 11/49 if I recall correctly. It had the property that it would expand when setting and crushed the casing of a hybrid circuit that we were testing. That takes some doing as I couldn't even put a tiny dent in the casing with my bare hands. -- Malc If you're swimming in a creek And an eel bites your cheek That's a moray
From: PC Paul on 29 Jul 2007 17:39
Malc wrote: > as I said they were potted as > well. In a compound called X 11/49 if I recall correctly. It had the > property that it would expand when setting and crushed the casing of a > hybrid circuit that we were testing. That takes some doing as I couldn't > even put a tiny dent in the casing with my bare hands. > Eww.. I guess that potting compound must have had redeeming features - I've only ever used ones that didn't expand at all. Got bloody hot, though... Were you making the hybrids, or buying them in? It all gets very strange working at that sort of scale - things melt and stick just from pressure, and you can barely see what you're working on, even with a microscope. And even then, ICs (hybrids just use the bare chips) don't look like they could possibly do anything, they're just covered in grey 1970's curtain patterns... |