Ever seen this before?

“Regular” being once every 5-6 years if the brakes on my black Inbred are a gauge.

For those saying the brake fluid is corrosive then what do you think it is in contact with inside the brake? – edit see this already covered a few times!

Problems with car brakes are caused by water getting into the fluid and causing corrosion from within. This should not really happen to aluminium.

From the picture it looked like a crack from the hose banjo. Maybe there was a defect in the material or from manufacture that has cracked when the bolt was tightened? Or maybe the banjo bolt has been impacted, cracking the caliper. Would need to take a better look tbh.

edit: and yes, probably a lot of corrosion from road salts, maybe fertilisers from fields etc etc. Once you have corrosion pits it is only a matter of time and it is under high pressure and the crack follows the fluid path so it will crack somewhere around there when weakened or a mounting point due to braking forces – A caliper is so small with no excess that they can pretty much break anywhere.

Teamslug has it…

Thats why none of his other bikes or ours have the same problem, it isnt from outside causes, thats why I said let Hope see it in my earlier post, pretty sure they see more alluminium parts than we can ever dream of.

I didnt want to say the word “defect” as I have respect for Hope products, and i doubt this issue is any fault of theirs.

Wouldn’t there be corrosion on the disc rotor, or on the contact points between the rotor and it’s alloy spider as well then?

IS MY WHOLE BIKE GOING TO CRUMBLE INTO DUST?????

lol, possibly. It doesnt have to occour at the interface between 2 metals, they don’t even have to touch. Look at stuff like ships anodes, they have a lump of magnesium or zink bolted to the back of the boat and that stops the entire ship from rusting! And if working on a boats electrics you have to be very carefull about not connecting an earth wire to anything that could form part of a galvanic circuit. There have even been cases of boats suffering problems simply by plugging into the marrina powersuply which then links their earth to the marrina, and anyone elses earth, so a small fault on someone elses boat can lead to your propler litteraly dissolving!

Thats why none of his other bikes or ours have the same problem

I’ve got some mavic rims, a cannondale frame, a 1950’s quill stem and a pannier rack that all look like that. My money’s still on road salt, accelerated by some galvanic action (maybe even from stainless brake parts).

I knew wooden bikes were the answer…never heard of galvanic corrosion in the early 1800’s. I’ll get my chisels out!!!!

Tinsy I didn’t want to imply anything regarding the quality of Hope products as i’m one of there biggest fans..just trying to get to the bottom of it and throw a few things in the pot for folks who might know a bit than me. I think Hope would certainly pick up on something like that, maybe ‘manufacturing defect’ is the wrong phrase….replace with ‘ material defect’……

teamslug, your bang on the money I think… 🙂

My two-pen’oth…

I cleaned an aluminium component up once using steel wire-wool and the corrosion was horrific afterwards. The steel particals got into the alum and the elements did the rest.

Any history of cleaning the underside of the caliper with wire-wool or a wire brush?

I’ve had a Mono Mini post mount corrode quite badly quickly, as a result of road salt. It appeared to be a galvanic (yes Cynic-Al!) reaction with one of the steel bolts. The corrosion took about two days after being out on the road in really salted conditions and I think there was some snow left on the caliper, in a cold shed so it didn’t dry out, which created just the right environment.

I don’t doubt it could happen Hamish, but it happens where there is contact between the 2 metals.

Here, the mounting tab in the pic is perfect and the rest of the caliper is ****ed.

You may be right but the caliper was mounted to an adapter – which may have been a sufficiently different alloy to cause an issue.

To be honest it was more the smug LOL that got me. 🙂

Confession time. 😳 I checked the front caliper in the cold light of day and it has some corrosion, but not nearly as bad, in the exact same place. So my earlier statement that it wasn’t affected is wrong. Sorry.

Both calipers are now packed up and will be getting posted to Hope by Mrs Beagleboy tomorrow.

“Regular” being once every 5-6 years

One very 5-6 ride more like it 😉

juan, if you found the brakes needed “refilling” then they were broken and leaking.

Confession time. I checked the front caliper in the cold light of day and it has some corrosion, but not nearly as bad, in the exact same place. So my earlier statement that it wasn’t affected is wrong. Sorry.

That reduces the chance that it was a material/manufacturing defect. Does sound like you’ve ridden through something – and that would be something other than just road salt.

Lots of interesting theories, but you have all overlooked alloy weevils.

Referring back to my previous post about something where you may have ridden: http://www.npl.co.uk/upload/pdf/corrosion_control_of_agricultural_equipment_and_buildings.pdf

ride through much farmland?

Well, I posted my calipers down to Hope on Wednesday morning. I fully expected to pay for a new pair, but was curious to know what could have caused such severe corrosion. I honestly didn’t expect the postie to drop two brand new calipers off this morning, especially as I’d even managed to lose the receipt, so couldn’t prove where or when I’d bought the brakes, ( Merlin , 24 months ago).

The invoice simply stated corrosion damage. I have simply become a fan of Hope for life. Chapeau Hope

Nice one.

My mate and I bought Mono Minis at the same time years ago. I used mine more, but he had his bike on a rear mounted carrier quite a lot.

Years down the line mine were immaculate. The paint was gleaming and all the hardware was rust free.
His on the other hand were terrible, looked like someone had been at them with the tippex, and all the hardware was rusty.

I’ve seen in on his other bikes. The main difference is that my bikes never get a regular 70MPH salty jet wash on the back of a car going down the MI.

One hundred, and bravo Hope

So would Shimano just replace a caliper with ‘corrosion damage’?

I love great out comes like this!

Hope head set, BB and finishing kit will be order for the new build tonight!

I was just about to walk around the corner to my lbs and buy some shimano xt brakes. However I’m going to get them to order the hopes now

leftyboy – Member

So would Shimano just replace a caliper with ‘corrosion damage’?

Would a Shimano caliper melt like that in the first place?

Same old debate for warranty work- yes it’s great that they replaced the calipers with no hassle. But it’s not so great that they needed replaced. Hope are good at turning failures into successes and hats off to them for that.

Would a Shimano caliper melt like that in the first place?

maybe, who knows, because despite all the speculation we still don’t actually know what caused it.

Yup. Shame Hope didn’t tell us really, I’d be really interested to know myself. All we know for sure, is that it was cool 😉

I know, I’m kinda annoyed, I want closure dammit!

and it would be good to know so that we can all avoid melting our bikes too!

Would a Shimano caliper melt like that in the first place?

Same old debate for warranty work- yes it’s great that they replaced the calipers with no hassle. But it’s not so great that they needed replaced. Hope are good at turning failures into successes and hats off to them for that.
Every manufacturer will have parts that fail given the awesome riding and abuse inflicted on it by the Gods of STw riding..we can guess at the percentage per part but we dont really know. What we do know is that Hope seem to stand alone in just sorting it for you Free of charge…that is worth something.

Junkyard – Member

What we do know is that Hope seem to stand alone in just sorting it for you Free of charge…

Alone? Hardly.

Well I said seem so feel free to big up other companies who behave like this and I will add them to my companies I am happy to buy from list.
[genuine question] Not trolling/arguing so who else would you praise?

Here’s a couple I’ve had personal experience of

Formula- replaced parts on my Oros for free, they’re at least 5 years old. Also when they were changing UK distributors and the parts supply was a bit dicey while stock was changing hands, they sent me a free brake hose kit from italy because I couldn’t buy one locally. Very nice.

Cotic- replaced parts on my Hemlock twice, I’m a second owner and it’s out of warranty anyway, and also being used for stuff it’s not designed for.

Halfords- believe it or not- gave me a brand new wheel for my cheapo mtb when the freehub broke, again I’m second owner and provided no warranty evidence.

OTOH I’ve had pretty variable service from Hope- I’ve twice broken 12mm Pro 2 axles, they’ve revised the part now to stop it breaking but they’ve declined to provide me with the revised parts, they just send me replacement axles which will break again. Last time they did generously offer to sell me the new parts at RRP though…

Turner bikes also have a very good rep for repairs /help/assistance

WTF?! 👿

You mean I trawled through the whole post and I’m still non the wiser? Grrrrr. 😥

2Pure (Crank Brothers etc) – anyone had anything other than a great experience dealing with them?

Specialized seem to be consistently good at customer service.

Fishers are dong a great job with SRAM etc.

Preventative maintenance?

If it were mine Id have noticed it heading south long before the state its in now. I would either have replaced it or spoke with the manufacturer.

How long have you had the part and did you buy it new?

If my brake failed causing me to crash I would want to know why before singing Hope’s praises for simply posting me a working brake. pmsl