Brake Caliper Pistons

[anutz]

So - this is picture heavy...apologies....


I have had a go at with the pistons, had them out, with Wonder Wheels and some razors and wet and dry...


They look ok but some still have some rust or light marking on the edges....nothing that i suspect would cause and issue but i need input as i am a novice!


If i need to replace pistons i shall


Also the rear i had to split as the pistons would not budge and one still will not.....its a bit nackered so am looking for a 1000 rear to stick on...


Anutz!

[unfazed]

If mine looked like that I'd replace them.

[anutz]

All of em?

Some look ok or all buggered?!

[Dave48]

All of em?

Some look ok or all buggered?!


+1
The problem being that the movement of the pistons over time will damage the new seals allowing ingress of dirt/water exacerbating the problem.
Its a considerable expense but apart from routine cleaning/maintenance you wont have to do it again. Unfortunately you have inherited the cost of putting right previous lack of preventative maintenance!

[darrsi]

They're not great, but surely they can be buffed up a lot better than that?
I can understand if there was corrosion on part of the pistons that go into the caliper, but only one of them looks like that could maybe happen, the other 3 are still going to be exposed and not enter the caliper at all so shouldn't cause a problem.
They're unsightly and not perfect but so what, they'll be covered in shit again in no time, no matter how new they look going in.


As i said, one does look suspect though so if that can't be improved then at the very least that will need changing, but i don't think the others are bad enough to cause any problems, unless you buy some mega wide pads.
And use plenty of red rubber grease on refitting.


It's obviously your choice primarily though, and just my personal opinion.


If you ride all year round like i do the edges of the pots tend to look like that anyway, due to the amount of salt on the roads in winter, that's why i recommend cleaning the pistons with a toothbrush, brake cleaner then reapplying with red rubber grease at least once, or even twice a year if you can be arsed.   

[Fazerider]

 
Agreed, that particularly bad piston would be best changed. The brakes should be ok for the lifetime of one set of pads then.
The trouble with attacking them with abrasives is that you may have damaged/removed the chrome plating badly enough that corrosion will really get its teeth into the surface as the pads wear down. I would have heeded the advice about keeping them away from the wet-n-dry.

[anutz]

  well i think i will just replace the lot and start fresh with proper maintanence.....which i have no problem with - turns out a second hand bike is very expensive!
 
Just in the process of getting some idea of price from powerhouse as if i am buyin new pistons and seals i may as well get the done and forget about it
 
I can see what you mean with the abrasives - assume you mean the wonder wheels i used....
 
the wet and dray i assume also is a culprit for removing the fine finish?
 
Anyway will update as i slowy leverage money...

[anutz]

ok so - cannot afford to replace all 4 now so going to re-assemble and see what they are like, they did not leak before just stuck so surely i can get some safe mileage out of them - not going back on the road till and MOT in a few weeks anyway

[darrsi]

You have to be lucky, like i have been before, but sometimes you can pick up a whole caliper in very good working order for much less than it costs to replace parts.


As with all things on a bike though, prevention is always better than cure. 

[fazersharp]

Like has been said the bad bit is outside of the seals so I cant see a problem, rather than red grease (after fitting) would copper grease be better on those ends that are constantly exposed to keep rust at bay now that the chrome has been removed.
Why dont they make them from stainless steel is it just cost.

[anutz]

yep a little copper grease is what my friend suggested - i am just checking that the marks ARE above the fluid seal - one may be right on it so might change one piston....which i can afford
 
 

[darrsi]

    So you reckon putting grease with particles of metal in it being moved tight against rubber seals won't cause any issues? 


As advised, several times, on here, ONLY use Red RUBBER Grease.

[darrsi]

yep a little copper grease is what my friend suggested - i am just checking that the marks ARE above the fluid seal - one may be right on it so might change one piston....which i can afford

Does your friend not really like you? 


Just read that aside from the metal particles causing havoc, copper grease is petroleum based and will make the seals swell causing binding and will eventually cause them to perish.


Nice.......  

[anutz]

clearly he does not - will give it a miss and just re-assemble as normal

[anutz]

i think i might go and snap a few exhaust studs.....that was actually more fun! 

[fazersharp]

    So you reckon putting grease with particles of metal in it being moved tight against rubber seals won't cause any issues? 


As advised, several times, on here, ONLY use Red RUBBER Grease.

I waw thinking on parts away from the seals - like they tell you to do the back of the pads

[anutz]

so was i to be honest, on the bits i removed the chrome finish off etc....?

[Jules-C]

Keep the copper grease away from any contact with the calliper body if possible. It can encourage the aluminium to corrode if there are any scratches in the anodizing.  I normally use non metal based brake greases such as mintex ceratec for back of pads, brake pins etc

[fazersharp]

I suppose if red grease will protect just as well then best to be safe, I just get the impression that red grease is not as robust in staying where you put it as copper grease would be as it is made for assembly, just thinking rubber grease is sort of transulant/ watery  - not quite and dosent seem like it would stand up to the weather.

And if other grease is a no no with rubber - how come you pack rubber gatered joints on your car with non red rubber grease

[darrsi]

I suppose if red grease will protect just as well then best to be safe, I just get the impression that red grease is not as robust in staying where you put it as copper grease would be as it is made for assembly, just thinking rubber grease is sort of transulant/ watery  - not quite and dosent seem like it would stand up to the weather.

And if other grease is a no no with rubber - how come you pack rubber gatered joints on your car with non red rubber grease

Straight from the horses mouth.....


http://www.redrubbergrease.com/

[fazersharp]

I got a tub of the castrol one mmmmmm like a tube of just the ripple bit in raspberry ripple (only thicker, and red and dosnt taste like raspberry, and might kill me if I ate it all)

[anutz]

yes it might kill you if you eat it all....but there is only one way to find out....grab a spoon..... 
 

[Jules-C]

Traditional red rubber grease wouldn't kill you it was based on vegetable castor oil which people used to take to keep themselves regular.

The new ones are often synthetic based.

[fazersharp]

ooo ooo got to go got to go.









to the loo (I ate the tub )

[unfazed]

Some of the marks extend beyond the dust seal when the pistons are pushed home for fitting new Pads.

On the poor advice of copper grease on the Pistons I would have to question the persons knowledge of brakes, brake piston seals and copper grease. I have seen instances of premature wheel bearings fail from fellows coating the axle with copper grease, the copper getting into the bearings. In one case it was when a fellow asked me if he was fitting the bearings correctly after 3 failure in 18000 miles that I realised what he was doing.

The copper grease would more than likely cause premature wear on the seals.

I repeat what I said earlier, if mine were like that I would replace them. 

Brakes are not an item I would ever skimp on and the same applies to tyres.