tinyurl.com/7hh6wy
(pic link valid for 1 week)
In use (Punto heater switch) it had become harder to turn in cold weather to the point of risking shearing of the shaft. Strange though, it was still very stiff even with the backplate off. In other words - with just the ball and spring on the shaft in engagement.
I notice that there`s no grease on the ball or the housing on the right it works in. Grease it? Modify the spring tension - putting it outside design parameters?
Incidentally - I fitted a new one before noticing the old one was designed to be DIY friendly (£20 ;-( notice those integral housing clips. A certain manual said "Prise down" had I done that the central dash panel would have sheared the horizontally engaging lugs on the dash...
Great isn`t it? Can`t help thinking there is a gap in the market for better quality manuals.
I don`t really `need` help of course, but would be interested in what technical chat may develop
(as always ;-)
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As a certificated bodger of long standing I would chop a couple of coils off the spring, reassemble and test. If still too stiff, dismantle, chop two more off
- spray liberally with wd40 and reassemble.
should do the trick.
Happy Motoring in the coming year Phil I
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From the picture it is not obvious (to me) what keeps the rotating contact pushed against the 'backplate', am I missing something? was it concave and /or sprung?
The other questions that have to be asked,
did the spindle run freely in its 'bearing' when the ball is removed?
was the pressure exerted by the spring/ball only producing only a 'indexing or detent' feel or if the spindle was worn was it resulting in additional stick/slip 'friction' on the shaft?
Good to see a repairable part - are other Fiats like this? (reason will become obvious over the next few days!)
p
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I would smear some silicone grease on the shaft and its contact points in the housing. Also clear up the electrical contacts with some isopropanol and give them a smear too.
If you snip the spring you might just end up with a sniff switch and zero-to-little detent.
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contacts with some isopropanol and give them a smear too.
Smear with silicone grease? IIRC it is an insulator!
p
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Smear with silicone grease? IIRC it is an insulator!
And a corrosion inhibitor. If you install it dry you may have contact but you might get oxidation (caused by micro-arcing) and eventual contact loss. Greasing it will insure the oxidation doesn't happen.
Worked wonders on my wiper motor.
Edited by mfarrow on 02/01/2009 at 11:39
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I'm going to hazard guess here, and i'm going to put it to you the defendent Oilrag in this case, that whilst the good Lady Oilrag was out performing the good works (and bless her heart for the oh so needed work)
you took advantage of her absence and put exhibit 1 'a dismantled Fiat heater switch' upon the missing ''did you say 'missing' Rumplole?'', yes mylord upon the the missing Lady Oilrags kitchen table and then proceeded to take pictures of the exhibit in question.
You then no doubt removed the evidence and cleaned the table before the good Lady returned and upon close examination of her table could discern unusual stains...how do you so plead?..:)
Take him down.....
Edited by gordonbennet on 02/01/2009 at 12:03
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Hi Guys, thanks for the interest ;)
Guilty GB....But.... I`m allowed free range with engine bits though in the conservatory - in fact I`m encouraged because I usually give Lady OR a bill for servicing work on her car - at garage rates - then give her the money saved, folded in the bill, which often buys another ring/jewellry/watch - outright.
Naturally, i`m considered almost as a living God to be able to do that - as all of her same age - late thirties - female friends have to give it to the garage.... Who says DIY and thorough half time and distance servicing doesn`t pay?
;-)
1)The shaft turns freely
2)the detent action seems to be causing the resistance to turning the shaft
3)The two halves of the housing pressure clip together - producing a loading on the electrical contacts.
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Hi Guys thanks for the interest ;) the bill which often buys another ring/jewellry/watch - outright.
You are 2nd from the top of my SWMBO's hero list and She is well impressed. Top man.
We should start a school for education in how to treat a woman, these youngsters haven't a clue, that and their long term or non term car servicing..;)
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Regards to Lady GB too... Bet she has the least salt encrusted chassis in the area - thanks to your good self.
When are you going to post some pics of the workings of those sturdy beasts that you both drive. was there a sort of drain plug device - perhaps in a cupboard in the kitchen?
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Just got it off the kitchen table in time...............
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When are you going to post some pics of the workings of those sturdy beasts
drain plug device ]]
Am waiting for the mileage to get to half the recommended, and i'll fit and photo the fumoto oil drain valve in place and working, at present its residing on a bookcase in the living room.
2000 miles to go, we have cut back greatly on our mileage, and are becoming quite reclusive, a trait we are both happy to let be as we live in a very quiet hidden part of our town, i think we've done 5 miles since Christmas Eve.
I'll have to polish the surrounding undertruck area to give the impression of good maintenance too i suppose.
This is likely to be a major operation for me to post pics and goodness knows the mess i'm likely to make of the whole thing.
SWMBO's chassis is well treated and kept well preserved through regular wax-hoyling, the exhaust does look a bit naff as i painted it with heatproof silver paint, which appears to be keeping the rust at bay (it was looking pretty rough at one year), but i gave a second coat too soon/late and its gorn crinkly.
I don't suppose too many get under to check the exhaust finish, but i'll take a pic of that so you horrible lot can tease me mercilessly about it.
;);)
just off the kitchen table in time? is that a confession? shouldn't that be preceded by ''its a fair cop guv''
Edited by gordonbennet on 02/01/2009 at 15:55
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"at present its residing on a bookcase in the living room."
I knew it....;)
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I knew it....;)
In mitigation m'lud, the last oil change was performed by the Toyota dealer at first service, i could hardly ask them to fit the thing, even though Toyota Japan approve the Fumoto valve Toyota GB may look somewhat suspiciously at it, but i'm quite convinced the mechanic who services it in Sept will appreciate it (my dealer doesn't hoover the oil out).
And following many comments hinting at possible obsessive servicing i have decided against my better judgement to allow the oil to stay in for 4.5K instead of my more usual 3K. See you lot have taught me to care more for the environment.
I've now run out of excuses..;)
Edited by gordonbennet on 02/01/2009 at 16:15
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1)The shaft turns freely
When unloaded I assume?
2)the detent action seems to be causing the resistance to turning the shaft
Because its loading the shaft/housing bearing point. This has increased frictional surface area two fold, one by wearing the housing to the shape of the shaft, and two by removing the rough surface of the plastic, creating 'stiction' when you try to turn the shaft.
Unlike metal bearings, plastic bearings are not assembled with a usually oiled surface, and any friction heat is not lost locally, plastic being a much better thermal insulator. At the microscopic level, this causes the plastic to heat up and melt. A roughened plastic surface lets the plastic cool through increased surface area and trapped air around the contact point, which is constantly changing as the material rides over the imperfections.
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"When unloaded I assume?"
Yes, It loads up (too much) with just the detent in place and with the back of the switch off. The photo - if Zoomed - seems to show like new surface finish of shaft and housing. Shorten the spring?
There are three choices for grease on the back plate (and detent?) - Castrol HMP - Castrol CL water proof grease (surely not) or petroleum jelly. It occured to me that HMP would be the only one not to run off perhaps - in the extreme heat of Summer..
Anyway, It can`t have anything else due to it not being worth the expense and trouble to go out and get it.
Now ready for rebuild following opinion. ( before the ball gets lost )
;-)
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>>At the microscopic level, this causes the plastic to heat up and melt.
This suggests that you've got more than a passing understanding of the theory of friction & lubrication of solids Mike - is this your specialism?
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is this your specialism?
By goodness no!! In fact I was awaiting you to come along and tell me how wrong I was ;-)
I was trying to draw an analogy with the microgroove record, and my understanding that plastic is comparitively a very good insulator.
There's a lot of discussion (probably Internet urban myth and male cow extrement) surrounding the wear rate of vinyl records and how to reduce it.
Obviously there are several catalysts for this (tracking weight, azimuth, tangency, anti-skate, stylus shape etc) but there is a hardcore of audiophiles who believe wetting the record grooves lubricates the contact point between vinyl and stylus and prevents wear.
There is however a supposed drawback to this. The theory is that as the stylus passes through the grove, it melts and deforms the vinyl inside the contact area (remembering that the force:area ratio is surprisingly high). If you let the material cool by itself, it is likely to return to its original shape; however if there is liquid there to cool it immediately then the groove wall will remain in its worn position.
I have never practised what I've read though, and I've never seen or written it in any engineering journal.
Edited by Dynamic Dave on 03/01/2009 at 19:24
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it melts and deforms the vinyl inside the contact area
Fascinating ideas! - I've never thought about the local friction heating in that context.
The melted zone will be small when compared with the size of the contact, and when wetted, will be smaller still - the liquid will become the dominant heat transfer medium, and may even prevent the melting in the first place.
Years ago, I did some work on the optimisation of a grinding process, and there, the use of coolant sprayed at very high pressure against the direction of the grinding wheel rotation into the cutting area helped to prevent thermal damage to the parts being cut (and cleaned cutting debris out of the pores in the wheel).
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"wetting the record grooves lubricates"
A groove on the shaft then and lubricated by condensation off my hands? (they condense water out of the atmosphere in winter)
How do you cut the groove so that it plays Waltzing Matilda on being moved to position four?
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