'How to' change the calliper seals

I've searched through this website, but am unable to find a simple step by step (ideally with pictures) 'how to' on changing the calliper seals. (ideally for a 2003 K3 bike).
One calliper was binding, so I've cleaned the piston with brake fluid (I'll take it to work on Thursday and Friday) but thought it may be best to properly dismantle the callipers and change the seals. It looks easy and uncomplicated (well no harder than checking the valve clearances etc..) - am I right?

Also why do I need red rubber grease?

Thanks!

[Spiderman]

Not sure if there is a step by step anywhere on the site at the moment. The long awaited "knowledge base" is still a work in progress so for the time being a Hyanes manual might be a good answer.

I've done mine a couple fo times now and the biggest problem has always been getting hold of the gold dust like red rubber grease.

A few months back i put in a call to Castrol's technical helpline as i couldnt find anyoe near me who stocked it, not a single person on their list of "local stockists" had it.
A very nice chap called me back and we had a very nice chat during which he told me this... the red rubber grease is a vegetable based compound that will not interfere with or contaminate the brake fluid where as the other products are mineral based and may do. He went on to ask me if i knew the difference between vegetable based and mineral based to which i honestly answered NO. he said anything vegetable based would keep the seals in good condition and not contaminate the brake fluid...ANYTHING.
I thought i'd be funny and said i'd get the olive oil out then and use that. he laughed and said "got money to burn have you? Why use fabcy olive oil when chip fat will do I wanted to make sure he wasnt just humouring me and he said that he was being deadly serious and there would be no issue. So i did and there hasnt been any problems at all.

He also said that if i ddint feel comfortable about that then there is a guy on ebay who buys in bulk from them and resells it in small zip bags. he actually did a search in ebay for me while we talked and sad "i'll tell you what not to search for and thats "red rubber" cos you'll find lots of off topic things that will keep you amused but wont help fix your brakes, lol.

HTH

Have a look at ebay item number 250208714966

I've just bought a tub.

But why do you need it? The only thing I can think of is to help slide the piston in with the new seal on - in which case why not lubricate it with brake fluid (that can't damage the rubber as it's always in contact with it)?

How hard it it to get the new seal in on the calliper?

It keeps the grooves the seals sit in from corroding, normal grease or copper grease will make the seals swell or wash away and also contaminate the brake fluid. Red rubber grease is waterproof, provides corrosion protection for the alloy caliper grooves and won't attack the rubber seals or brake fluid.

Getting the seals into the caliper are a doddle, getting the piston in is easy too, but like everything that moves, it needs lubricaton not only to make it easier to move, but to provide cooling and corrosion protection - that's where the red rubber grease comes in.

Originally Posted by Aidan

I've searched through this website, but am unable to find a simple step by step (ideally with pictures) 'how to' on changing the calliper seals. (ideally for a 2003 K3 bike).
One calliper was binding, so I've cleaned the piston with brake fluid (I'll take it to work on Thursday and Friday) but thought it may be best to properly dismantle the callipers and change the seals. It looks easy and uncomplicated (well no harder than checking the valve clearances etc..) - am I right?

Also why do I need red rubber grease?

Thanks!

Aidan,

Watch out for the seized brake pad pins.

When you take it apart could you please post the diameter of the O ring that seals the two caliper halves?

Thanks,

John

[flymo]

caliper halves? I dont think they split on a K3, certainly not the front calipers anyway.

They only pistons on one side of the calipers.

Mike

Originally Posted by ejohnh

Aidan,

Watch out for the seized brake pad pins.

When you take it apart could you please post the diameter of the O ring that seals the two caliper halves?

Thanks,

John

whoops!! Ignore it! I didn't read the original post properly - sorry.

[Viney]

Originally Posted by Aidan

But why do you need it? The only thing I can think of is to help slide the piston in with the new seal on - in which case why not lubricate it with brake fluid (that can't damage the rubber as it's always in contact with it)?

How hard it it to get the new seal in on the calliper?

Because its the correct tool for the job. It prevents the pistons from sticking and to prevent the seals from corroding.

A quick how to.

You will need
14mm socket (To remove the caliper)
14mm Spanner (To remove the banjo)
8mm or 7mm Spanner (For bleed nipple)
Longnose pliers
Other pliers to remove brake pins if stuck
A pick of some kind
a scraper of some kind
Can of compressed air
a recepticle to catch fluid
New copper washers
New brake fluid
CLEAN RAGS of the non lint variety

1. Undo bolts of both calipers and let hang
2. One at a time pump lever to move pistons further out of the caliper (Dont let them pop out yet
3. When you are satisfied that the pitons are near the point of coming out Drain the fluid and remove a caliper from the bike one at a time.
4. The pistons should just wiggle out. If not, use the compressed air down the bleed nipple (Open) and put your thumb over the banjo hole. Be careful, the pistons will fly out, so stuff a rag in the caliper.
5. You will then see you have 2 seals. A Dust seal and a main seal.
6. Hoik them out with a tooth pick or similar
7. You will see that there is loads of white stuff. Scrape this out using a pick or a scraper of some kind being careful as not to damage the caliper body or the groove that the seals sit in.
8. Clean with brake cleaner and dry with the compressed air
9. Smear the new seals with the red rubber grease and insert.
10. The haynes states the larger of the seals has to go in only one way, its doesnt, its square in section, not chamfered liek the manual says.
11. Do the same for the dust seal
12. Clean the pistons up using a rag and if you have some scotchbrite
13. Smear the red grease over the piston and slide into its bore
This should cover one caliper. Do the same to the other side.
Clean the caliper up and give the pins a good clean.
14. Re-fit the calipers to the bike and bleed the brakes making sure that the pistons are sliding freely.

Thats a basic guide. you may encounter things along the way, but if you are going to tackle it, then i hope you have some mechanical knowledge. DO NOT DIP THE SEALS IN BRAKE FLUID, use the red grease. I got 2 sachets from a local motor factor (Not halfords) and done many calipers, and still only half way through one sachet.

Excellent stuff Viney- this will really help me when I do my calipers over the weekend, put my new pads on and new hoses.

I assume for draining the old fluid, I can just attach a tube to the bleed nipple and then open the reservoir to let it run out? It's my first time messing with brakes, see.

I get the feeling my pad pins will be well seized- what's the best stuff for un-seizing them? I don't fancy drilling the calipers.

Incidentally, I got some red rubber grease from MGOC at this address-

http://www.mgocaccessories.co.uk/aca...rease_176.html

About ?8.20 for delivery- first class delivery. The 500ml tub will last you forever...!