Ball joints

[Guinney1971]

This might be something that Rich Hanlon could have a look at, as he deals with metal fatigue as part of his job - might be worth having a chat to him - he might be able to assess the failed ball joint(s) and let you know.

This next part is a bit OT, but in a way echo's what Chris was saying. We brought the Avantime out of storage last year to put her back on the road (and get the LPG conversion done), and she went into Renault for a 36k service and MOT. At this point, the car had done 32,000 miles in 7 years, so nothing really for a modern car.

We were told that she'd failed the MOT on play in the steering arms. Apparantly a common failure on Espace's (the Avi is based on the Mk3 Espace) and on Laguna's. We'd noticed a 'bump bump bump' when going on full lock, for instance when manouevering in a carpark, but didnt realise what it was. On the Avi (and Laguna and Espace), you cannot just replace the steering ball joints at Renault, you have to replace the whole lot, arms and all, at £300 a pair (plus fitting of course). There was that much play in the arms that you could wobble the front wheels back and forth!

Also, this is a problem that in the main only affects the 3.0 V6 Avi, not the 2.0 Turbo apparantly due to the wheel sizes - the 2.0 Turbo has 16" rims, the 3.0 V6 has 17" rims that are also wider - with the option of 18" wheels too (they look the mutts nuts 8) )

[stunned_monkey]

Rissy Wrote:Tried to phone Martin. He's changed his number. I've obviously bugged him one too many times! ha-ha!

Just a quick note - my mobile is the same as it has always been and I can now use it at home. BT are a buch of useless ****wits and actually cut us off rather than let orange take the line over, so we had to wait 2 weeks to be reconnected and THEN only with a different number :twisted: Anyway, just use my mobile number now. (although am up to my eyes in exams right now)

Yours has failed due to good old fashioned wear, Stu's is another example of a failure of one of DMCH's new joints. The threaded part simply isn't strong enough. Also looks like a lovely example of crack propagation....

[Rich Hanlon]

Quote:as he deals with metal fatigue as part of his job

Well, keep the fracture surfaces in good condition, drop them in a jiffy bag and I'll take a look in my spare time. Sounds nasty. Might be able to tell if its an initial material defect or a corrosion pit etc that was the initiator, as Martin says it's probablt good old crack prop stuff thereinafter.


da/dn = a(Delta)K^n and all that...

[Chris Williams]

Quote:da/dn = a(Delta)K^n and all that...

:? :? :lol:
Chris

[stunned_monkey]

Beach marks are a dead giveaway of crack propagation prior to ultimate failure.

[Guinney1971]

this is quite serious really, and if it is an 'inferior' metal that is being used to make these for the DeLorean, it makes you wonder how many other sorts of cars that the same material is being used to make ball joints and other components for ..........

[Rich Hanlon]

Quote:Beach marks are a dead giveaway of crack propagation prior to ultimate failure.

Indeed so! Nasty eh?

Depending on the spacing you might be able to tell if it was High Cycle fatigue - rapid crack growth at low amplitude (eg caused by a vibration) or low cycle fatigue - fewer cycles at lower speed - (eg once per speed hump or something) - but with a greater stress reversal each time.

However, having said that, that's all acedemic really, neither is satisfactory! Yet another one for the black museum!

(I already have a fossilised 40 year old Morris Minor fuel line, a old timing chain about 1/2" longer than a new one, a rusty Nissan Micra ball joint that pulled out of its socket rather than the tapers splitting, a supposedly new Allegro master cylinder full of corrosion pits right along the inner bore, and a (literally!) molten set of Renault points in my personal collection!!)

As the bloke at the garage next to where I work says - "I hate cars, me..." :wink: