Is there a trick to putting o-rings into the front caliper?

[Spudly]

I finally got around to getting the Passive Aggressor back on the road and ordered all the bits I think I'll need, including carb diaphragm, float bowl seal, front brake pads and so on.

When I pulled the front pads off, the piston looked like this:

https://i.imgur.com/RHUnjgF.jpg

Looked a lot worse than this actually, because when I last had the thing apart I stupidly used rubber grease on it and the high temperatures had turned it into a rock hard coating of stuck brakingness.

Obviously I needed a new one.

So, after various parts screwups and so on, I ordered the new one, along with the piston seals and other bits I'd missed the first time.

So, now I have the caliper off the bike and I've cleaned it up a fair bit with my dremel and wire brushes etc and the inside of the caliper actually looks pretty good.

Now I'm trying to put everything back together and I feel like a giant gynecologist at a midget sexual health clinic. Is there a secret to getting these o-rings into their channels? I thought I had it once but there was absolutely no way the bucket itself was going to enter the caliper.

I have 500g of copper grease and a big G clamp, but from what I've seen on my research, it really shouldn't take all that.

Help me BCF, your my only hope.
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The Old Apprentice

[Vincent]

You're 100% sure they're the right seals? Have you still got the old ones and something to measure them accurately with?

Are the grooves completely cleaned out of any oxidisation?
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Space Is Deep

[Spudly]

Cheers for the reply.

From what I can tell they are definitely the correct ones - can't really compare to the old ones because they fell apart when I was removing them. The replacement piston is correct and the seals came attached to the piston (bought as a kit). The bottom slot in the caliper is shiny clean, the top one seems clear, but it's still discoloured and in all likelihood has a couple of lumps and bumps in it which aren't helping.

I have a feeling I'm going to have to get that properly cleaned aren't I?
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The Old Apprentice

[Islander]

They can be awkward to fit but should go in place with a bit of careful manoeuvering. If they won't fit then you've still got some corrosion in the grooves. Stick a bit of red rubber grease on them before you fit them - it'll help them seat,

[Vincent]

Yeah......you'll need to get the grooves back to the original metal. It doesn't take much to make the seals catch on the piston and get pulled out.

If you have any bits of the old seals, at least you could check the depth.
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Space Is Deep

[Raffles]

You don't want to be using Copaslip on your brake pistons/seals. I only ever use clean brake fluid as a lubricant for such tasks.
As others have said, your going to have to remove all of the crud from inside the grooves in order to be successful.
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A good loser will always be a loser.

[Spudly]

Right then thanks very much guys. I'll pull the dremel thingy out again tomorrow and see if I can get rid of that corrosion gunk.

Awkward bloody thing it is. I'll try for some photos tomorrow as well.
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The Old Apprentice

[slowlydoesit]

[c_dug]

I've been cleaning up some callipers in my spare time at work, I've found the right angle end of a scribe to be the best tool for cleaning the seal grooves.

https://www.cutwelmetrology.co.uk/images/ww/product/7230-zi.jpg

Assuming you don't have such a tool to hand you could probably replicate the effect with a bent nail or something.
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I am a bellend, I am a man of constant sorrow, I am a gummy bear, I am a rock.

[Rogerborg]

Nearest supermarket, toothbrush section, look for a dental pick. If you're lucky it'll come with a mirror, which is also handy for various spannering purposes.
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Biking is 1/20th as dangerous as horse riding.
GONE: HN125-8, LF-250B, GPz 305, GPZ 500S, Burgman 400 // RIDING: F650GS (800 twin), Royal Enfield Bullet Electra 500 AVL, Ninja 250R because racebike

[kramdra]

Your doing it wrong. Dremel/wire brushes have no place near a caliper unless your trying to strip the paint from outside


Removing seals - best tool is a wooden match, cut the head off with a slight concave curve. This is essential for master cyl seals without damaging them. Toothpicks or plastic are a poor substitute, too weak and metal can damage them.

Dont use metal to clean the seal grooves. Kitchen scourer is ideal, but clean caliper well afterwards to remove abrasive particles.

Give Seals a very thin coating of red grease, if you can see it, its probably too much. Seals should fit nicely into place and stay there. It takes some effort to remove them.

Pistons should slide in easily with moderate thumb pressure.

Fill system with a syringe from the caliper bleed nipple as its far easier.

[sickpup]

[Spudly]

Apparantly there is a song that goes:

Finished with my woman 'cause she would not help me with my bike

And luckily for me I'm not going to be that guy.

I was in the living room swearing, cursing at the damn thing and genuinely considering buying a new caliper from Suzuki when my wife came in from her dad's place, saw my rage and sent me off to the shop for beer.

While I was gone, she fitted both seals into the caliper. She went in dry, no lube apart from what was already on it (not much), but the thing is in!

I married the right one!
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The Old Apprentice

[Islander]

You do realise you have to hand back all your man points now, don't you.

[Rogerborg]

Songs: but she don't like Firefly?

Probably fitted them back-to-front to cash in on your life insurance.
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Biking is 1/20th as dangerous as horse riding.
GONE: HN125-8, LF-250B, GPz 305, GPZ 500S, Burgman 400 // RIDING: F650GS (800 twin), Royal Enfield Bullet Electra 500 AVL, Ninja 250R because racebike

[Raffles]

[Spudly]

[Vincent]

[Itchy]

If they absolutely do not fit, check if your bike is stock.

I had been riding my CBR around for at least a year, then parts I bought for it didn't quite fit, puzzled I looked at parts numbers.

It had a firestorm front wheel (which meant the std CBR discs did not fit), and 3 pot brakes.

The rear swing arm was off a later bike and was therefore a bit longer as well.
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Spain 2008France 2007Big one 2009 We all die. The goal isn't to live forever, the goal is to create something that will. In the end, your life will flash before your eyes. Make sure it is worth watching.

[Spudly]

I wanted to wait till the caliper was completely back together before completing this thread. Thanks for your help, a combination of advice from here and some offline help managed to get things back together properly.

The parts were definitely right for the bike, but I suspect the bits which came off were in fact the original parts - considering it's a 2006 model, it would explain the condition of the old parts and the incredible amount of cleaning which had to be done in order to make them fit.

Getting the bucket in was the last challenge. On the youtube video, the bucket seemed to just slide in with a gentle twist and some brake fluid to lube it. Mine needed a machinist's press at a friends precision toolmaking factory. Now it's in, the bucket moves nicely and appears to be making a nice seal, so the o-rings weren't unseated by the press, so with luck, I'll be putting it all back on the bike tomorrow and having it work properly.
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The Old Apprentice

[TUG]

The trick is to place your thumb on it bang in the middle and press it gently with some rubber grease or if you're in a tight spot some brake fluid, it will just slide right in no bother.

EDIT: You had to use a press to get it back in properly? Wait... What? That doesn't sound right?
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Haz ER-5, innit!