refresh caliper seal O ring?

HI,

I finally got round to splitting my rear caliper cos I couldn't get the brake pad pins out. The seal between the two halves is not like a normal O ring, it's more like a rubber washer.

There was some mention on another thread(which I cannot locate) about refreshing rubber seals by immersing them in hot water. Could I do that with this seal? I have ordered the full kit for replacing all the seals but it seems a waste to have to just use the one seal out of it. Yeah, I know I could strip the pistons and replace all the seals but what's the point if they are not leaking and the pistons move freely in the bores?

Oh, I managed to get one pin out intact but the other sheared off at the caliper body so I had to drill that out. Copper grease should be ok to lube the new pins now shouldn't it?

I noticed that the caliper has two bleed screws. Is it the normal procedure to bleed through one and then, when that half is bubble free, to bleed thru the other?

Cheers.

[yorkie_chris]

No idea about the O ring, manual says replace it though.

As for the fluid seals, don't replace them, strip them and lube them though.

The o ring seal should be good to go. Give it a clean and pop it back in. Because of it's shape it should be still in the correct shape and not need reshaping.

If you can get them, replace the pins with stainless steel. You'll never have that trouble again. Also yes, use copper slip grease to put them back in. Every now and then take it back out, clean, re apply new copper grease and put back in again.

Bleeding.

Bleed the outside one first, then the inside one, and then the outside one again for good measure.

[dirtydog]

Originally Posted by ejohnh

HI,

I finally got round to splitting my rear caliper cos I couldn't get the brake pad pins out. The seal between the two halves is not like a normal O ring, it's more like a rubber washer.

There was some mention on another thread(which I cannot locate) about refreshing rubber seals by immersing them in hot water. Could I do that with this seal? I have ordered the full kit for replacing all the seals but it seems a waste to have to just use the one seal out of it. Yeah, I know I could strip the pistons and replace all the seals but what's the point if they are not leaking and the pistons move freely in the bores?

Oh, I managed to get one pin out intact but the other sheared off at the caliper body so I had to drill that out. Copper grease should be ok to lube the new pins now shouldn't it?

I noticed that the caliper has two bleed screws. Is it the normal procedure to bleed through one and then, when that half is bubble free, to bleed thru the other?

Cheers.

If it was me i'd pop the pistons and do all the seals whilst the caliper is apart.
copper grease will be fine for the pins. as for the bleed nipples when i serviced my rear caliper and fitted braided hose i bled from both nipples back and then front

Thanks for advice guys. I got 2 pattern pins coming from Wemoto. Should be here tomo and fitted.

No leaks at all from pistons so I'll use the same seal between the calipers and keep an eye on it.

What was that about refeshing seals though?

There seems to be a definite reaction between the mild steel of the pins (and also one of the clamping bolts) and the caliper metal.

Thanks guys.

[yorkie_chris]

Originally Posted by ejohnh

Thanks for advice guys. I got 2 pattern pins coming from Wemoto. Should be here tomo and fitted.

There seems to be a definite reaction between the mild steel of the pins (and also one of the clamping bolts) and the caliper metal.

Are they stainless ones?

There isn't a reaction, it's the welding gnomes.

[the_lone_wolf]

Originally Posted by ejohnh

...refreshing rubber seals by immersing them in hot water...

how could you?

Originally Posted by the_lone_wolf

how could you?

Ah!! I should be scourged!!

No they are not stainless. Dunno where I would get SS pins from anyway.

Many years ago, before I started in computers, (Devonian?) I did a Mech Eng HNC in Willesden Tech. College. In that course we found out about why and how things corrode, why Galv steel is normally self healing - stuff like that. Giving up electrons and stuff.. The details are vague now but I am sure I recall something about the
electrostatic gradient between different metals or alloys of metals being involved. (blimey how nerdy is that?)

Stuff arrived from wemoto today. Seals kit included a small container of red rubber grease. But no brake pins - apparently they had to order them from Holland FCS! So I cancelled them and gonna pick some up frm Thunderoad. Pain, but got to be done if I want the bike for this weekend.

got the pins from TR.. put caliper back on - Bled it no prob at all. Back on the road.. And I didn't use any of the new rubber stuff!!