Has anyone successfully repaired a caliper with a set of the pistons on AliExpress? I have cracked the originals in a saint caliper.
A new caliper is ~£100, a set of pistons about £50 (plus luck of the draw getting them from China).
https://h5.aliexpress.com/item/4000449086466.html
Won’t they expand when they get hot? They seem
Expensive to take a chance on.
Everyone knows you don't repair shimano, you just replace it.
If you want to fix a caliper then buy some hope ones.
1) is an expensive fix that may or may not work
2) is it worth risking it when it comes to brakes?
As above you'd be mental to risk £50 and all the time and faff on the dodgy pistons.
New caliper time.
The lack of serviceability is one of the reasons I moved away from Shimano (that and the wandering bite point). I had about 8 dead brakes laying around at one stage and figured that not being able to repair (only replace them) wasn’t terribly good for the environment in the long term.
I bought the kit. The ones I got have a ceramic core inside the alu body, so v little heat transfer.
No way I spent £50 on them. Maybe £18?
I bought them because the failure was a cracked piston, not corrosion around the seal area.
BUT in the true STW style I haven’t yet fitted them so can’t tell you if they work. Soz.
Blob, I'm going to guess you bought the XT/STR single pistons - they're available pretty widely for not much money at all. It only seems one place you can get the Saint ones.
The other alternative is buy an XT m8120 2-pot (or secondhand XTR) caliper and replace.
Just seems so ****ing wasteful.
What about a Magura calliper and go Shigura?
<blockquoteEveryone knows you don’t repair shimano, you just replace it.
If you want to fix a caliper then buy some hope ones.
1) is an expensive fix that may or may not work
2) is it worth risking it when it comes to brakes?
Ignoring the fact that there's a thread on here from a guy who replaced all the seals in a Hope Mini only to find that calliper corrosion meant that they leaked regardless of the seals.
Theoretical serviceability doesn't always turn out to be practical.
Same thing happened to me (just one piston was damaged).
I've just fitted one of these in my 105 calipers and it's holding up so far:
https://www.ebay.co.uk/itm/Hope-Caliper-Piston-X2-/324240375136?_trksid=p2385738.m4383.l4275.c10
From what I've read the Hope pistons are slightly deeper than the Shimano ones so you might struggle fitting pads if you have to do both sides.
Ignoring the fact that there’s a thread on here from a guy who replaced all the seals in a Hope Mini only to find that calliper corrosion meant that they leaked regardless of the seals.
Hope horror stories are few and far between (apart from cranks) and usually end with returning to hope for a replacement. Hopes customer service is legendary.
Funny thing is I only use hope hubs. I don't like their brakes. They look lovely but I'm just used to the feel of shimano and I accept you need to replace bits from time to time and cant service them.
I don't imagine a piston is going to get that hot on a pushbike for expansion of the metal to make any noticeable difference.
Your current piston cracked, and you're still alive, so I don't see the harm in trying an alternative. I don't expect it could break any worse than the crack you already have.
I'm more curious about the join between the ceramic and metal parts, as that could be a point of weakness.
For that price, tbh I'd probably just bite the bullet and do it properly. Maybe sell your current one for spares. Different story if they were £10!
What about a Magura calliper and go Shigura?
I wouldn't bother - given that the shimano levers/master cylinder failure rate is only a bit less than the calipers. Go full Magura.
what shimano calipers are £100??
Saint
Has anyone tried using pistons from cheap shimano calipers?
Just struck me I have a unused MT200 in the shed I could put the pistons into a more expensive set if they fit?
I don’t imagine a piston is going to get that hot on a pushbike for expansion of the metal to make any noticeable difference.
ythey can get up to a couple of hundred degrees c or even more. Never seen a blued disc?
Having said that the alloy body will be expanding as well
I'm afraid I haven't, but expect you'd need a pretty heavy rider dragging the brakes quite a lot to reach those sorts of temps? I don't expect it's something many of us would encounter!