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Discussion Starter #1
My "front-end" saga continues with the discovery of seized brake caliper pistons and brittle caliper piston seals (that have been in there since 2001)

Having never done this before.....Is this piston good for re-use? It seems to slide in and out of the bore ok, but looks a bit pitted/scored?

IMG_20190908_142903.jpg
 

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I would reuse it (but appreciate many wouldn't), never seen brittle seals personally.
The secret is to properly clean the seal grooves in the caliper body, I normally smear in a bit of red rubber grease, wiping away the excess once the seal is in place

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I'd replace - I think there are stainless steel replacement versions available. And as above if corrosion gets in the seal recesses in the calliper that causes the aluminium oxide corrosion to push the seals out to make it bind. So a good cleaning out along with new seals, with some red grease should be good for getting through Winter and beyond.

Coincidently just had to service mine yesterday due to similar - I was able to pump both pistons out quite far using a thin metal plate and then just finally wiggle them out. For really stubborn pistons I have in reserve a piston removal kit to avoid damaging them.

https://www.ebay.co.uk/itm/Motorcyc...ind-Back-Removal-Garage-Tool-Set/323456672541
 

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Discussion Starter #6
ok, so..

red grease for pistons...
green grease for slider pins...
and a different grease for wheel bearings...
 

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Discussion Starter #8
ok, do i use red grease to lubricate the new seals and pistons, or use brake fluid? or do i use both?

>Not many people repack the sealed wheel bearings.

according to the haynes manual i should grease the wheel spindle and put some on the speedo drive thing and on the spacer, i assume this is just normal grease?
 

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I personally use red grease in the seal groove to help keep corrosion at bay, wiping the excess off once the seal in place then a light smear of brake fluid on the seal face to moisten before inserting the piston, as ever, others may have an alternative view.

Anything oily based is fine for the spindle (I've used everything from old engine oil to grease & waxoil) - it's just to stop it corroding to the bearings & spacers.

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Discussion Starter #10
mmm..ok. after researching this opinions seems to differ, some people say use brake fluid and never use grease, others say the opposite!
 

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Red grease is a non-petroleum based grease, for rubber components. Petroleum based products cause them to swell over time, hence not using them on brake seals. If you can't get red grease, you can use silicone grease. I've dealt with a brake refurbishing company called Bigg Red, in Brum, who uses it out of preference; they say that the red grease hardens over time and silicone doesn't. They do thousands of systems for all sorts of vehicles, so I'm happy to take their advice, but you should make your own mind up about brakes; it's your life.

Be sparing with the grease; a thin coating is enough.
 

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mmm..ok. after researching this opinions seems to differ, some people say use brake fluid and never use grease, others say the opposite!
As with most varying advice, read the info available and go with what you feel comfortable with.

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I've been reading up on what grease for brake slides pins, there's so many conflicting opinions. Apparently BMW Cars say no grease required, then there's copper, red, normal, ceramic, silicone etc. I've received silicone from Brakes Int with seal kits but you only get small sachets.
 

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Most places charge ridiculous prices for tiny tubes of silicone grease. But I got a 500g tub from a plumber's merchant for less than £10 ages ago. I don't know what the price would be now, as I'm still using the original tub:D

Just to be clear, I use the silicone grease to give a light coating on the seals and grooves, to make sure they seat properly. Then I wet the cylinder walls and piston with clean brake fluid before assembly. As well as lubricating the piston, it helps free air bubbles from sticking to the dry surfaces, especially the rough-cast base of the cylinder. It's surprising how much air can be held this way; I leave the assembled calipers full of fluid for a while, to let all the bubbles rise to the bleed nipple, before pushing the pistons fully home and expelling the fluid. After a first ride, I bleed them again; there's often still a tiny bubble or two in there.

As far as I know, the red grease is only intended for rubber components, it's not meant to be used as a lubricant for metal-to-metal parts. The same goes for silicone grease. For metal-to-metal moving parts, stick to the conventional petroleum based greases.

One issue with grease on metal brake parts is that the high temperatures will soften or melt it, risking contamination of the friction lining. Some manufacturers avoid this by assembling dry, others use minimal coatings of high-melting point grease, on critical areas only, such as anti-sqeal shims and the sliding faces of the pad carriers or pins. I prefer to use copperslip on steel parts, but that is said to cause corrosion on ali components, so be careful with it. Whatever you put on, winter salt and grime will get in there, and no grease is a substitute for regular cleaning. And with the crappy cast cheese Nissin use, that means an annual strip down.

All the above is a personal view; as has already been said, make your own mind up, and if in doubt, get professional advice or get a professional to do it for you. You could try calling Bigg Red; I've always found them helpful, and as they service most makes, they must be aware of the conflicting views.
 

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I've been reading up on what grease for brake slides pins, there's so many conflicting opinions. Apparently BMW Cars say no grease required, then there's copper, red, normal, ceramic, silicone etc. I've received silicone from Brakes Int with seal kits but you only get small sachets.
What do you mean by slide pins?

There are the pins that retain the pads (for these, I personally use a VERY light smear of waxoil, purely to keep corrosion at bay, as I do the caliper area around the pistons & exposed piston surface too).

For the caliper sliding mounts, anything petroleum based will distort the dust seals in time (so I use red rubber/silicone grease).

Another option is use a Honda or even Haynes & use what they say.

My priority (other than safety) is keeping corrosion at bay.

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I've received silicone from Brakes Int with seal kits but you only get small sachets.
You only need a small amount, just enough for a light smear on the rubber components and maybe the grooves they go in. There's more than enough in the sachets; if you run out, you're using too much! It's not like vaseline, you know......
 

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Discussion Starter #17
well, this subject has certainly divided opinions. i think i will just use brake fluid on the seals and pistons!
 
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