Are caliper seals square in section, or what?

[TamSV]

Having rebuilt a score of calipers over the last couple of years, for myself and others, I'm probably coming to this question a bit late.

Every manual I've looked at (and a fair few peeps on internet forums) say the main seals are wedge shaped in section and need to go in a certain way. But every seal I've actually used, OEM or pattern, have been square.

So far I've been chucking them in any old way (after convincing myself they're square) and neither me, nor anyone whose brakes I've worked on, has been involved in a fiery ball of death type incident.

I've mostly worked on Tokico calipers from various Suzuki's but a couple of Nissin calipers have also been through my hands. I'd swear all the seals are square. I've just spent 15 minutes staring cross-eyed at a new Tokico seal. It's bloody well square.

So am I fick, blind or what? Do some calipers differ? Has the design of seals changed at some point? Are people on the internets talking sagely about a job they've never actually done?

Answers from trustworthy sources are requested, because if it turns out I'm wrong I've got some brakes to check before the afore-mentioned fiery ball of death occurs.

[squirrel_hunter]

That is an interesting question.

I do check seals to see if they have a taper before I install them. But off the top of my head I can only remember encountering one set of OEM seals that were. However I can't remember what bike that was from...

[yorkie_chris]

The manuals are full of sh*t, they're mostly square except for some odd ones. I think MZ may have been wedged.

[speedyandypandy]

Didn't know there where anything else than square seals. I've yet to service the old brembo, AP and nissin 2 pots I have(I think I have 10 front and 5 rear calips laying about) wonder what I'll find there?

[jambo]

As above.
I suspect the same diagrams have been doing the rounds for some time, being ported across to the next manual as they are generally accurate. I'm certain that there are tapered seals, but they're not from any of the bikes I've worked on.

Jambo

[NTECUK]

All our (Nissan) car ones are square.
Reff EBC brake artical
" it is worth remembering that pad retraction in any caliper is totally reliant on seal 'pull-back'. Caliper seals are essentially square in cross section"
http://image.mustangmonthly.com/f/9166102+w750+st0/mump_0209_understanding_ford_brakes_11_z_disc_brak e_caliper_piston_seal.jpg

[Sid Squid]

On occasion I have encountered a seal that isn't square in section - but it's been quite obvious, no squinting needed to discern so.

[Viney]

Mine are round. Hth

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[TamSV]

Thanks for the reassurance. I rebuilt another org'ers calipers at the weekend and obviously I would hate for something bad to happen to him.....he still owes me beers. :)

I had been looking at another forum where a couple of people I would normally listen to said the seals on the RGV were tapered, which made me wonder, as the OEM set I've got in the garage for that very bike looked extremely square to me.

I suspect some people are staring at these seals until they begin to imagine a taper. :rolleyes:

[muzikill]

I used a set of jewellers loupes to double check mine during my caliper rebuild and they were fine either way.

[Sid Squid]

I've tried mic./vernier on them in the past, awkward - they're rubber. Always square as a square thing, unless they're not, but you can tell straight away if that's the case.

[johnnyrod]

I did that too, turned out I had just done a crap job on the calipers and rebuilding them properly fixed the problems!