Where do the O seals go?

[Vetus Ossa]

I removed the bolts holding the calliper as, I was having trouble stopping pad rub on the rotor.
I cleaned every thing up, and copper crested the threads put it all back together and set the pad gap again.
All good now with no rub.
When i looked down onto the floor underneath the calliper I, saw the two pictured O seals on the floor, that has to be part of the assembly,
Question is, where do they go, and are they necessary/essential.
Cheers if you can help.

[531colin]

No picture of O rings?
Are they seals, or the paired cup & dome washers that let the calliper seat on the mount other than exactly parallel with the mount?
Haven’t explained that well but hopefully it’ll do?
….. like Vee brake blocks so you can set the angle to the rim

[Cyclothesist]

Colin they're sitting on the chainstay under the caliper

[Cyclothesist]

2 thoughts:
- they're off something else and not important
- they're piston seals that have popped out and are important.
Put the wheel back in and check the brakes work without leaking.

[Cyclothesist]

No picture of O rings?
Are they seals, or the paired cup & dome washers that let the calliper seat on the mount other than exactly parallel with the mount?
Haven’t explained that well but hopefully it’ll do?
….. like Vee brake blocks so you can set the angle to the rim

[slowster]

..that has to be part of the assembly...

Not judging by the EV doc.

https://dassets.shimano.com/content/dam ... -4544A.pdf

I would be reviewing what else I had undone/worked on in addition to the caliper, and also what tools I had used. For example, similar size O rings are used on many derailleur hanger alignment tools, although I am not suggesting that is where the O rings are from in your case

[Vetus Ossa]

The brakes are 100%
The seals are too small to go over the bolts without stretching, so confused, not unusual for me tbh.
Something Colin said about dome washers has me thinking as there was one under one of the mounts, between it and the frame.

[Stevek76]

I think they may just be intended as 'helper' things to stop other things falling off the bolt, so probably below the 3 washers.

But are not critical, just makes it less annoying to dis/reassemble.

[Brucey]

I wonder, could it be intended that the 'o' rings go on the split pin, either side of the spring? This way, when the pads are worn, it might bring the disc OD into (noisy) contact with the spring, thus alerting the rider.

[Vetus Ossa]

I wonder, could it be intended that the 'o' rings go on the split pin, either side of the spring? This way, when the pads are worn, it might bring the disc OD into (noisy) contact with the spring, thus alerting the rider.

Don't think so Brucey, but Stevek76, has me thinking that maybe they went here (see pic) to hold the lot together and came off the bolt when I withdrew it??

[Brucey]

I wonder, could it be intended that the 'o' rings go on the split pin, either side of the spring? This way, when the pads are worn, it might bring the disc OD into (noisy) contact with the spring, thus alerting the rider.

Don't think so Brucey, but Stevek76, has me thinking that maybe they went here (see pic) to hold the lot together and came off the bolt when I withdrew it??

surely they are too small for that?

[Vetus Ossa]

I wonder, could it be intended that the 'o' rings go on the split pin, either side of the spring? This way, when the pads are worn, it might bring the disc OD into (noisy) contact with the spring, thus alerting the rider.

Don't think so Brucey, but Stevek76, has me thinking that maybe they went here (see pic) to hold the lot together and came off the bolt when I withdrew it??

surely they are too small for that?

Agreed they look too small, but took a bolt out and it stretched over easily enough, did look stretched so maybe it doesn’t go there.

[531colin]

An O ring between the frame and the brake is the last thing you want, isn’t it? That needs to be 100% firm contact.
It looks to me that Vetus has part of a set of dome/cup washers under a bolt head; no use at all, you need dome/cup washers BOTH sides of the calliper on both bolts to be able to change the angle of the calliper relative to the adapter.
Has somebody been messing about with it?

Look at the other brake and see if there are any pesky O rings visible.

[Vetus Ossa]

Noted Colin, thank you.
It is set up as it came to me from the shop new, but will check out what you mention.

[PH]

It looks to me that Vetus has part of a set of dome/cup washers under a bolt head; no use at all, you need dome/cup washers BOTH sides of the calliper on both bolts to be able to change the angle of the calliper relative to the adapter.

I thought the same, I can't see the purpose of them where they are, yet they're like that in the Shimano exploded diagram posted above.