Mikes Brakes

[Kickstart]

Hi

Mike came round tonight so that we could bleed his brakes. Had a quick session with them, then decided to clean the calipers up a bit. At this point we found this brake connector:-

https://www.alfa-pages.co.uk/TempPicture/mikesBrakes.jpg

Guess who isn't riding home tonight.

Lesson for today - don't touch alloy connectors on braided steel hoses.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[McJamweasel]

Holy shit!
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BCF: Be yourself, just don't be an arse.

[MarJay]

Race fittings... anodised...



Lucky man...
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British beauty: Triumph Street Triple R; Loony stroker: KR1S; Track fun: GSXR750 L1; Commuter Missile: GSX-S1000F
Remember kids, bikes aren't like lego. You can't easily take a part from one bike and then fit it to another.

[Sparks!]

He don't have much luck with brakes and stuff does he (or was the split line Col.? and wasn't it mike with the fooked car wheel?)
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Current Toys: 06 Yamaha WR250F | Nissan 350Z GT | Tech 4 Homes

[McJamweasel]

The split line was me, the fooked tyre was him.
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BCF: Be yourself, just don't be an arse.

[Robby]

What is it with north and brakes.

[jayluvmito]

aluminium fittings tend to have a habit of splitting hence being sold as 'race use only'
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one day...

[WildGoose]

nothing to me with me

although that might explain the fade they used to have

it was pointed out from the garage, that altho he didnt fail the MOT because of them, he would advise me to change them
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So in other words, he stopped you for being flagrantly in posession of a motorcycle in direct contravention of the Hippies, Darkies and People Whose Face I Don't Like The Look of (Police Powers) Act. 1976

[Mr C]

I guess it's different metal corrosion between teh steel and aluminium

a bit of electrolyte in there (salt water) and off you go - rotting away underneath you



they're ok for race use because if they get wet they will be changed and if they don't they'll probably be changed anyway


mine are all stainless steel on Hel lines
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187.3bhp = 201mph

[Kickstart]

Hi

I mentioned them to Mike some time ago. Lucky he came round to bleed the brakes and so this was noticed. We were wondering who fitted the hoses, so if not Goose then presumably Box Hill Motorcycles.

Think the main problem with the alloy fittings is that as they are tightened up it is inevitable that some of the anodising is scratched off, so allowing corrosion to start on the unprotected alloy.

By the way, the other caliper was almost seized onto the pins it slides on. The brakes now have very little travel and work well. Pity we will have to bleed them again tomorrow.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[WildGoose]

they were on the bike from purchase, i would be surprised if box hill did it to be honest, unless the rubber hoses were really bad

in which case they may have been installed in early 90's whenever the bike was first used, then may have been sat in a crate on a dock (as the typical grey import saga goes according to magazines) to corrode away

who knows, a bit slack on my part, but the brakes were always good enough
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So in other words, he stopped you for being flagrantly in posession of a motorcycle in direct contravention of the Hippies, Darkies and People Whose Face I Don't Like The Look of (Police Powers) Act. 1976

[Kickstart]

Hi

Suspect that they were UK sourced and not Japanese sourced. Not heard of a Japanese import coming into the UK with braided hoses already (not sure they are legal at all in Japan, those ones would certainly be illegal in many countries).

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[Claud 14.7 to 1]

[Mr C]

now I'm sure someone will come along with a far better explanation that I can possibly come up with given that my metallurgy is at least 12 years old


every metal has a kind of electrical potential, and they are all different
... scratch that - here's an explanation of galvanic corrosion from a good googling


Galvanic corrosion tends to occur when dissimilar conducting materials are connected electrically and exposed to an electrolyte. The following fundamental requirements therefore have to be met for galvanic corrosion:

Dissimilar metals (or other conductors, such a graphite).
Electrical contact between the dissimilar conducting materials
(can be direct contact or a secondary connection such as a common grounding path).
Electrolyte (the corrosive medium) in contact with the dissimilar conducting materials.
When placed in an electrolyte, different metals/alloys assume different corrosion potentials (refer to the galvanic series in seawater). It is this potential difference that is the driving force for galvanic current flow. The less noble material in the galvanic couple will become the anode and tend to undergo accelerated corrosion, while the more noble material (acting as a cathode) will tend to experience reduced corrosion effects. However, in some cases, chemical species produced at the cathode can degrade certain cathode materials.

basically a current flow is set up (electrons moving from one metal to the other) which results in the degradation of one of the metals.. this is pretty much how batteries work

it wouldn't matter if the line was stainless or not as the connector is ally and would have a similar galvanic potential difference to either steel or stainless steel - the result would be the same

I dare say a stainless steel hose with an ally connector would suffer accelerated corrosion, actually making it worse as I think Chromium is further away from Aluminium on the galvanic scale - although I couldn't swear to that (the main difference between mild steel and stainless steel is the addition of chromium inclusions)

the key to avoiding this in engineering terms is to make sure that wherever you have metals in contact, you should try and make sure that they are not too dissimilar in terms of galvanic potential, obviuosly steel and aluminium are a fair way apart (as an example, zinc and carbon are 1.5 volts apart, this is why zinc carbon batteries are 1.5 volts as a single cell)


in summary

keep yer tarty aluminium brake bits - they are dangerous, they rot and they aren't as strong as steel in the first place, but hey I'm sure you'll feel the benefit of the 0.1 grams saved in weight

make sure your banjo and other connectors are stainless or at least steel you know it makes sense
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187.3bhp = 201mph

[Zx6man]

when in all weathers on my old zzr600, the brakes were stripped every week to keep em in good nick, I used to do them while waiting for the missus to get ready for work. A lot of folk tend not to check their bikes over if nothing seems wrong.

[Claud 14.7 to 1]

Ok i see, so the salt water would be acting as the electrolyte. The addition of electricity, in this case is not required. The difference in the metals would be enough to cause the corrosion (with the addition of salt water soultion)...

The key is to keep metals that are in contact, identical in material. TBH i would have thought that all the parts used would have been stainless steel anyway, obviously not.

Interesting and helpful, thanks Mr. C!

I vaguely remember this stuff from GCSE chemistry...

[Mr C]

yes you see, the stuff they teach you at school does often have a real world application


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187.3bhp = 201mph

[Mr C]

and having thought about this, I have just been out and fitted the rear Hel line that has been sat in my garage for aeons

probably be sliding around with the rear all locked up now as the OE one was shite
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187.3bhp = 201mph

[Kickstart]