Shimano brake calliper information

The Rookie

I have the parts breakdown and technical instructions off the Shimano website for my new (to me) Shimano brakes, however the parts breakdown doesn't give much info on the parts of the calliper itself (body, seals, pistons etc) just the bits that bolt to it (hoses, pads, pin, bleed screw etc) am I missing something?

I have two questions I'm trying to answer
1/ Front is a Saint M800 calliper, looks like it may be the same as an XT M775 or possibly one of the XTR's, can anyone confirm if it is? (knowing Shimano it will be a mix and match, for example the pad retaining pin is a different Pn to XT and XTR!)
2/ Rear is a Shimano XTR M965 calliper, looking at this advert http://singletrackworld.com/forum/topic ... imano-spds it looks like the the only difference between front and rear callipers is the mounting 'leg length' for disc sizing, can anyone confirm that? (rear having longer legs for '+20mm' 160mm discs, front being sized conventionaly for a direct fit for 160mm discs, anyone confirm that?)

nicklouse

2. IS mount calipers? yes for the same size disc you have different mounts due to the 20mm difference. covered in the FAQs. So a rear caliper for a 160 will need a 180 if fitted to a IS fork.

1 what do you really want to know? yes it will work with any shimano lever assy.

The Rookie

Thanks Nick, I was pretty certain on point 2 just clarifying.

Point1, Just trying to understand the make up of the calliper in terms of parts compared to XT or XTR really, what is 'chop and change' able between them as I have the XTR 965 front and wondering if any parts are worth robbing from it if they improve the M800 (PM forks).

For info they're likely to be paired to some M775 XT levers I've got coming, athough I'm considering a pair of the earlier dual control (well single casting mounting) levers - M755 - I know that all Shimno callipers work with all levers.

nicklouse

well as the main difference is the caliper its self i would say dont bother and sell it.

The Rookie

I may just sell it, but they aren't worth much so if I could improve the M800 I'd rather do that, or even just keep it for component spares...I presume you mean the main difference is the calliper body (casting)?

Is there anywhere manuals for stripping the calliper (removing pistons, changing seals etc) as I can't find any on the shimano techdocs site, also something with service part numbers, or are they just considered a black box item?

The Rookie

As my Question appears to have slipped attention, what I'm trying to find is any instructions for stripping the calliper down (removing pistons), what tools I may need etc etc....is do Shimano sell it as a 'black box' item that if it fails you just bin it?

supersonic

Does the Shimano tech docs cover the parts? Worth a look.

The Rookie

No they don't, in the tech docs it lists every part number except the calliper body with pistons/seals etc and closure plug, all the peripherals are on their like bleed screw, Banjo bolt and seals etc....

mister p

Shimano callipers are not designed to be taken apart hence why there are no details of internal parts on any of the tech docs. From memory M800 callipers are the same as M765 callipers but in a different colour.

Yes the legs on a rear IS XTR calliper are longer than the front IS. There was an option of 140mm on the rear with XTR, all you do is put the front calliper with the shorter legs on the rear.

The Rookie

Thanks Mr P sir, I had sorted the IS calliper options now and understand that (160rear with rear calliper, 140 rear with front, 160 front with front calliper and 180 front with a rear calliper, and then adaptors on top LOL!).

Thanks for the info on the callipers, PITA but there you go, I had sussed it was 'very similar' to the M765 XT, which I have the docs for as well, shame I was loking forward to upgrading it with some XTR bits!

mister p

I am unsure as to why you would want to strip a Shimano calliper. You would have to buy an entire calliper to get the parts so I would just put that whole unit on instead of risking wrecking two callipers.

The Rookie

Because I have PM mount forks, the M800 body is PM, but the XTR IS, so on the opposite line of thought, why if they are 'better' (aka lighter - I don't know? do you) would I not fit the XTR internals from a calliper I can't conveniantly use into the one I can? The main benefit of just using the XTR calliper (weight) will likely be offset by adding an adaptor and 2 bolts, so that's pointless, but if I can lighten the M800 calliper before fitting that would be a bonus.

Maybe I'll get a cheaper one to pull apart as a learning exercise!

mister p

The difference in weight between an XTR and an XT / Saint calliper of that age is tiny. Most of the difference comes from using Ti backed pads in the XTR. So stick Ti pads in the Saint, same result for minimum bother.

njee20

You're considering the comparative weight of pistons and seals? Chapeau, that's a new level of nerdyness!

The Rookie

PMSL, not sure your meaning that as a compliment!

Point is as an engineer I like to explore all my options, as someone who can't justify throwing money at my bike (I'm not a good enough rider) I like to get the very best out of what I have rather than just getting out the checkbook, so yes if I could save say 5g a piston by swapping I would, heck I weighed all three BB cable guides I had when building the bike to use the lightest!

Mr P, good point on pads, being the main difference, still I'll check the weights when I have the bits!

njee20

Kool Stop used to do alloy backed pads, which were lighter than ti. Dunno if they still do. Superstar did them for a while, but they stopped.

The Rookie

Uberbikes still do...not much dearer than steel, but only Organic from the quick look....will check again!

But then ally backed AND lighter pistons........

Plenty of people split 2 piece callipers and pop the pistons out (avids), so why not a 1 piece......

njee20

Not all Avids are two piece, you can still pop them out, but spares are available if you damage a seal or something. I'd not fancy rebuilding a brake using old seals, totally pointless affair.

The Rookie

Not all avids, no.......

Thanks for all the advice, once I've got the bike running on the new brakes I'll decide whether I'm going to strip the spare XTR or sell it on.....

Maybe be generous and upgrade the daughters front XT to XTR......