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Re: Big green puddle in Tesco's car park...

Posted: 29 Aug 2009
by mickey taker
we occaisionally get them on here

docchevron1472 wrote:you can attack the back end from beneath, although access is still a bit shit TBH..
:D

Re: Big green puddle in Tesco's car park...

Posted: 29 Aug 2009
by Philhod
:lol: :lol: Read a few copies of VIZ, donkeys years ago. It was it's graphics that were the selling point then.


:? Don't remember any Finnbar though.....probably an age thing :P I' ve retired while you've been away.

Re: Big green puddle in Tesco's car park...

Posted: 03 Oct 2009
by mat_the_cat
Finally got round to changing the offending cylinder, and this is what I found:
Image

The wall hadn't corroded through, but the rod from the piston to the rear arm had snapped just after the ball joint and was contacting the arm in a different position. Hence when the suspension was on maximum, the piston had travelled past the first rubber seal and the return pipe was seeing full hydraulic pressure. I've kept the old cylinder, as I can see nothing wrong with it - all it needs is a new rod and gaiter and I'll have a usable spare. I guess that when the other side corrodes through again I'll just swap the gaiter and rod onto it.

Re: Big green puddle in Tesco's car park...

Posted: 03 Oct 2009
by Philhod
Had it snapped or had it corroded almost through?

I've always thought the gaiter does more harm that good.

Re: Big green puddle in Tesco's car park...

Posted: 04 Oct 2009
by mat_the_cat
Definately smnapped, although I'm so pissed now I can hardly type! I replaced both struts about 3 years or about 50k miles ago, and everythig looked in good nick when I replced the spheres in the summer (also I did the rear arm bearings the previous year).
Breakage was clean, no signs of corrosion. It had actually dug a recess in the arm where the rod was pressing, so must have been doining it for a while...

Re: Big green puddle in Tesco's car park...

Posted: 04 Oct 2009
by smiffy
I need to find a pair of rear cylinders, mine are just about fucked!

Re: Big green puddle in Tesco's car park...

Posted: 04 Oct 2009
by Philhod
I've had success digging them out and welding them up TIG, but unless I can get into college I have no TIG set now :x

Re: Big green puddle in Tesco's car park...

Posted: 04 Oct 2009
by Way2go
Philhod wrote:I've had success digging them out and welding them up TIG, but unless I can get into college I have no TIG set now :x
Is this failure not a sign of fatigue then that's indicative of the whole thing starting to crumble? :?

Re: Big green puddle in Tesco's car park...

Posted: 04 Oct 2009
by Philhod
No. The aluminium corrodes in specific places, somewhere around the btm of the gaitor.

Seeing as aly doesn't corrode much, in dry conditions, I always wonder if it doesn't "sweat" inside

Oh, and repairing with magic metal lasts about 48 hrs :)

Re: Big green puddle in Tesco's car park...

Posted: 06 Oct 2009
by mat_the_cat
The ones I've seen there has been a tide mark inside the steel housing that supposedly protects the strut, where this has filled up with mud/water. I reckon this has led to galvanic corrosion of the aluminium (basically if 2 metals are in contact with each other, either directly or via water then the 'lesser' metal, in this case aluminium, will corrode)
I'd previously drilled a couple of drain holes to hopefully prevent this...time will tell

Re: Big green puddle in Tesco's car park...

Posted: 06 Oct 2009
by docchevron132
Bi-metallic corrosion...
I wondr if bi-sexuals get the same thing?
Ya know, corroding flanges due to juices of varying make up...

Re: Big green puddle in Tesco's car park...

Posted: 06 Oct 2009
by Philhod
Yeah,! It's due to a current passing through the frame all the time.

Back in the 70's they used to put aly trim roung wheelarches etc. then wondered why rust appeared :roll:

They developed a blue paint primer to stop the reaction.... electrophoretic or something like that.

Re: Big green puddle in Tesco's car park...

Posted: 07 Oct 2009
by Way2go
The Fin Stabiliser systems we supplied for boats contained a block of ally in the outer pod which was known as a sacrificial anode as that was attacked by electrolytic action rather than the metals of the mechanism. It was something as the name suggests that needed to be replaced periodically.

Re: Big green puddle in Tesco's car park...

Posted: 07 Oct 2009
by Philhod
Anode that [coat]

Re: Big green puddle in Tesco's car park...

Posted: 07 Oct 2009
by Vanny
they do that on barges in a big way, massive huge sacrificial chunks.