Caliper bolt seized

stranger12

Hi guys,


Old caliper gone and nipple was stripped

Bought another second hand, seized and stripped .....

Looking around that is common fault as thread is aluminum on evo 8 calipers

I am fes up with this, planning to buy another one. Should i apply grease , will it stop this happening.

I read somewhere they use aluminum paste but not sure what it is

BeenThroughItAll

*aluminium.

You could use ceramic grease or aluminium assembly paste, but only a small smear is necessary.

You could also try reusing the original thread about calipers, rather than a new one.

facade

You can buy aluminium paste anti-seize from a bicycle shop, usually has graphite in as well.

The problem is the different metals corrode if they contact electrically and get any salty water near them (it is what happens to LandRovers) so you want them not to touch. Japanese bikes generally use a weak threadlocking compound to provide isolation, some people suggest a layer of PTFE tape round the threads.

I've never figured out why aluminium paste between aluminium and steel would be any better than nothing TBH, it does work between the aluminium frame & seat post on my 'bike though.

Molyslip do a ceramic anti-seize, recommended for alloy & steel, it is non conductive and is supposed to stop electrolytic corrosion.

I have seen recommendations for a zinc based anti seize, specifically for iron & steel into alloy, but I don't know where to get it from.


On a fixing bolt I use screwlock, I generally just smear copaslip on brake nipples and not worry, but I might try a layer of PTFE tape next time

BeenThroughItAll

facade wrote: »

You can buy aluminium paste anti-seize from a bicycle shop, usually has graphite in as well.

The problem is the different metals corrode if they contact electrically and get any salty water near them (it is what happens to LandRovers) so you want them not to touch. Japanese bikes generally use a weak threadlocking compound to provide isolation, some people suggest a layer of PTFE tape round the threads.

I've never figured out why aluminium paste between aluminium and steel would be any better than nothing TBH, it does work between the aluminium frame & seat post on my 'bike though.

Molyslip do a ceramic anti-seize, recommended for alloy & steel, it is non conductive and is supposed to stop electrolytic corrosion.

I have seen recommendations for a zinc based anti seize, specifically for iron & steel into alloy, but I don't know where to get it from.


On a fixing bolt I use screwlock, I generally just smear copaslip on brake nipples and not worry, but I might try a layer of PTFE tape next time

Some good points - whilst for some reason it's considered 'wrong' to use PTFE tape on bleed nipples, it does help prevent seizing and also prevents air being introduced into the bleeder when using a vacuum device, making the bleeding process much quicker and more efficient.

stranger12

What is this type of drill called?

http://www.fraserbrowneng.co.uk/store/index.php?route=product/product&path=60&product_id=51


Would you take the guy work that it can take a lot of pressure 2000 psi?

Do you reckon helicoiling be string enough to hold the nipple?

It is my life and don't want to it to pop under pressure

molerat

All that kit does is drill out the hole, tap a new thread and insert a bleed nipple adaptor. A correctly fitted helicoil will be fine, aircraft components use them all the time.

kaffenback

Notwithstanding the fact that running a Mitsubishi Evo hardly fits the MSE Forums money saving ethos in the first place

Put a light smear of a copper based anti seize compound, e.g. Copaslip, on the nipple threads. Copper will protect the aluminium from the action of galvanic corrosion when in contact with steel. Also if you repair the internal stripped threads in the caliper, as suggested with a thread insert kit, e.g. Helicoil or Recoil, or get a machine shop to do this, this is probably both cheaper and superior to getting a used or even a brand new caliper, as you will then have a much stronger and more corrosion resistant stainless steel thread, but still do use Copaslip or other copper based ant seize on the nipple threads, hope this helps

BeenThroughItAll

stranger12 wrote: »

What is this type of drill called?

http://www.fraserbrowneng.co.uk/store/index.php?route=product/product&path=60&product_id=51


Would you take the guy work that it can take a lot of pressure 2000 psi?

Do you reckon helicoiling be string enough to hold the nipple?

It is my life and don't want to it to pop under pressure

We went through this in your last thread didn't we?

An Evo with shoddy home-upgraded calipers, an M5, and aspirations to purchase a new GTR/Mustang/E63 AMG.

How very unlikely/interesting.

stranger12

kaffenback wrote: »

Notwithstanding the fact that running a Mitsubishi Evo hardly fits the MSE Forums money saving ethos in the first place

Put a light smear of a copper based anti seize compound, e.g. Copaslip, on the nipple threads. Copper will protect the aluminium from the action of galvanic corrosion when in contact with steel. Also if you repair the internal stripped threads in the caliper, as suggested with a thread insert kit, e.g. Helicoil or Recoil, or get a machine shop to do this, this is probably both cheaper and superior to getting a used or even a brand new caliper, as you will then have a much stronger and more corrosion resistant stainless steel thread, but still do use Copaslip or other copper based ant seize on the nipple threads, hope this helps

Thanks


Only top few threads are gone so i am thinking i could helicoil the top bit only

fishybusiness

Only top few threads are gone so i am thinking i could helicoil the top bit only

Why would you? If you have the tools, do it properly.

No shortcuts with brakes........

stranger12

Didn't feel like waiting so helicoiled it and it is fine

It seems to go all the way down and hit the base / seat of the nipple bleed however it has one thread above the other one.

I know the nipple sitting on base is inportant but how much? Is it the pointy bit that blocks the hole?

If it doesn't sit and block the hole, can fluid come up through the thread!

One bit i am stuck with is, i have around two threads left on top which i don't want to remove as doing so will twist the helicoil and pull it out.

Is it ok to leave that two threads on top?