[Closed] seized BB7 inboard piston

never had it happen - how long since you last adjusted the inboard pad ?

might it be cross-threaded somehow ?

(plusgas, I assume)

Edit: since you've snapped off the stub you can get it out destructively. Can't imagine that's be hard to do

Mine did the same recently, commuting through two harsh winters just corroded it to a point where it would no longer work! Replaced both calipers. I have 2 new 140mm rotors for sale as a result if interested!

[url= http://cdn.sram.com/cdn/farfuture/bN7LPXFNZN2ShC8NrhYiKlYLc-bVfqiXCPenrf9IoMk/mtime:1316452980/sites/default/files/techdocs/service_manual_bb7__bb5.pdf ]overhaul guide in case you don't have it[/url]

Same issue al.

New ones are entirely different design - funny that

I replaced the knackered ones with deores

Cheers guys - no spares so I'd prefer to save it if I can. The torx bolts appear to be seized also so I can't get the caliper apart.

May shop for new ones then 🙁

Jeez they actually recommend grease in reassembly?

Jeez they actually recommend grease in reassembly?

Mine came with grease in from new, not just in reassembly 🙂

With moving parts in rolling and sliding why would you not grease them?

Cos it will melt?

Think I drilled a couple of holes on a diameter and used circlip pliers to turn a seized pad on the old design. The new design isn't much better, but it does have a hex head you can get a socket on when the pad eventually seizes.
It's the major failing of BB7s; they just don't stand up to year round commuting. Does anyone have first hand experience of the materials in the new Shimano road discs, and how they fare in winter conditions?

I've used an air compressor on the hose connection to get the piston out of the caliper on a car - although, thinking about it, I'm not sure if the pressure is any more than you can apply using the lever as in normal use.

cynic-al - Member
Cos it will melt?

Same here - off to buy a new one tomorrow 🙁

Seems to be the inboard one as it gets adjusted far less than the outboard. it is the easiest to remove and grease up, so that's what I'll do next time. Second one to go, too.

Copper grease on the inside adjuster from new and they will keep going even here riding in salt water on the coast. Leave it dry and it will seize solid in no time, can stll be used with the inner seized, it kinda becomes like a BB5! 🙂
I just aline them by eye (white paper underneath to see the gap either side of the disc)once they seize and keep using them until they rot with corrosion usually for me around 2 years, still amazing low maintenance disc brakes,

Happy to have anyones BB7 calipers that have a seized on the inner for my beach bikes... 🙂

Stripped and rebuilt the winter-affected caliper just recently thanks to the spectacular assembly manual.

But I was forever adjusting them due to wonkey rotors so nowt had the chance to seize.

There should be a BB7 graveyard for this thread 'cause I need a new cap for the adjustable pad side.

you can buy adjuster caps pretty cheap - [s]can't remember where , ebay prob[/s] got mine from tartybikes

I'd say remove as many plastic parts as possible and leave it soaking in paraffin or diesel for several days and see if that manages to free it off.

Coastkid - you're welcome to it but Royal Mail postal prices probably don't make it worth the postage these days. Happy to hand it over on Edinburgh, London, York or Bristol as those exotic locations are where work takes me. Email in profile.

cheers scaredy

Anyone know whether the new spare would fit my old caliper?

Well I drilled out the piston thingy it wasn't too tricky.

However I don't think a replacement is available 😐

However^2 Ultegra calipers look very lovely 😎

Are they the cx75's? Be interested in how you get on with them.

I'll report of I do buy them. They look good, and it seems serendipitous that I get trade price and can justify a purchase!

ANyone know if the new piston would fit in the old caliper?

Wll after some ignored emails and a call, Fisher tell me I cannot get a spare.

Is the caliper any use to anyone without one?

I assume that you've trawled through the evilbay? I managed to get an arm for the outboard piston

Ta - I'll have a butcher's.

cheers for the link Del, something to do on a quiet night.

Presume mine are the 2012 model, inboard piston has always been stiff, normally use torx bolt rather than plastic wheel to adjust, not seized yet probably due to frequent adjustment.

Anyone know wjhy the instructions say rotor should be closer to outboard pad than inboard?
outboard>_|__<inboard
you're pulling the rotor further across then, seems a daft idea.

BAck to this...do the current calipers avoid this seizing problem?

Mine never seize, even after a few years of almost daily abuse. Pretty obvious to me when I bought them that a drop of copper slip on the threads would be a help. Always do this when new pads go in. Silky smooth which they were not as new.

Nice guide to getting a stuck inboard piston out, with plenty of pretty pictures [url= http://www.auntiehelen.co.uk/tag/avid-bb7-disc-brakes/ ]HERE[/url]