Front brake caliper overhaul...

[Blapper]

So after I did the front fork oil change on the SV, I though 'while I have the front up, I suppose I could service the front calipers'. I've seen it written on this forum about yearly overhauls and thought 'nah, that's ott innit - I don't do enough miles, rarely get wet and never salty' and they seem to work just fine. Bike's only done 8500 miles. But on the other hand, I haven't done them yet, the bike is 15 years old and the previous owner didn't say he had serviced them...

Wow! I found one seized piston, a whole tube of copper grease had been used and the calipers were full of jelly - looked a right mess. I suppose I should have done it when I changed the brake lines.

So new piston and a set of seals ordered, brake fluid and RRG in stock, will be interesting to see if they feel different when reassembled.

The moral of this story is: This forum is great for advice - take it! =D>

[sl0th86]

Whoaa! Yeah i had a look at mine to try to get rid of that squeaking but mine seem ok phew!


Sent from my iPhone using Tapatalk

[SV650rules]

The only place copper grease should be used is on rear of pads - even then proper Molybdenum grease is better, proper silicone brake grease should be used on gaiters , slide pins and seals, normal greases made from hydrocarbon base will cause seals to expand and will damage them.

[tom_e]

Silicone grease isn't great when used in a metal on metal situation such as the slide pins, I'd pack them with RRG.

[SV650rules]

Silicone grease isn't great when used in a metal on metal situation such as the slide pins, I'd pack them with RRG.


Red rubber grease is for rubber to rubber and rubber to metal, not metal to metal, it is just a non-petroleum (vegetable and silicone) base grease , not really a good metal lubricant - when I ordered new slide pins for my car brakes they came with a sachet of white silicone brake grease. If you want to really get it right use a ceramic or molybdenum loaded PTFE grease on slide pins, but I have used TRW silicone white brake grease on cars and bikes for years and never had a problem.

[Blapper]

This looks like a decent deal that covers all bases:
http://www.ebay.co.uk/itm/Castrol-Red-Rubber-Grease-Lithium-Copper-Set-Brake-Caliper-Piston-Seals-O-Rings-/191849135082?hash=item2cab197bea:g:DDoAAOSwL0NXENb H

[Craig380]

So new piston and a set of seals ordered, brake fluid and RRG in stock, will be interesting to see if they feel different when reassembled.


How much is a rebuild kit (seals & piston), out of interest please?

[nutzboutbikes]

Silicone grease isn't great when used in a metal on metal situation such as the slide pins, I'd pack them with RRG.

Silicone grease is fine to use in a metal to metal situation except when a high melting point grease is needed, not sure were you got that information from buts its wrong.

[nutzboutbikes]

Red rubber grease is for rubber to rubber and rubber to metal, not metal to metal, it is just a non-petroleum (vegetable and silicone) base grease , not really a good metal lubricant - when I ordered new slide pins for my car brakes they came with a sachet of white silicone brake grease. If you want to really get it right use a ceramic or molybdenum loaded PTFE grease on slide pins, but I have used TRW silicone white brake grease on cars and bikes for years and never had a problem.



I to use silicone grease on the slide pins/bolts & on the caliper seals when fitting them no problems here either.

[Blapper]

@Craig380 - £46 for a stainless steel piston and four sets of seals. From now on the cost will just be grease and brake fluid as the calipers will not be getting in such a state.

What about Lithium Grease chaps? Is that petroleum derivative based?

[SV650rules]

What about Lithium Grease chaps? Is that petroleum derivative based?

Both lithium grease and vaseline are petroleum based.

[tom_e]

Silicone grease is fine to use in a metal to metal situation except when a high melting point grease is needed, not sure were you got that information from buts its wrong.

https://www.acc-silicones.com/applications/lubrication.ashx
http://www.abbeysupply.com/Abbey_Silicone_Gun_Grease1.html

Both recommend not using on metal to metal contact.

[Blapper]

OK, so silicone grease is no good for the sliding pins, what about ceramic grease?

[nutzboutbikes]

http://www.ebay.co.uk/itm/271642430344?_trksid=p2060353.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

[Bibio]

RRG is fine for everywhere on callipers and yes that includes the back of pads and sliding pins. the only place i recommend using copper grease is blind holes for the pad retaining pins. btw if pads have anti squeal shims then you should never use a grease on them as well, that defeats the purpose of the shims, the shims should be dry.

RRG is not a silicone grease its a vegetable based (synthetic) grease with additives designed for rubber to what ever. its primary purpose is to keep the rubber form drying out and to form a barrier against ingress of water. think of it as a very very thick pure synthetic oil. RRG is also very high temp melting point. the reason its red is so that you dont go putting it on high speed bearings such as wheel bearings by mistake due to it not having anti wear additives. its fine on slow speed stuff like sliding pins though.

think about how much the sliding pins actually move.. its ermm about 1mm at a time for the piston stroke and over a total wear of pad about 4-5mm. the piston and the sliding pins have a direct coalition of movement.

top tips:
dont go mad with RRG, you only need a smear of the stuff. when coating the seals rub the grease into the seals by putting RRG between thumb and fingers and rubbing the seal all round. pack the clean seal recesses with RRG, install the prep seals then remove excess RRG with your finger.

coat the piston in a very very lightly in RRG then slide into calliper.

same goes for the gators, lightly coat the rubber in RRG inside and out. smear some RRG on the sliding pins then assemble into dry holes, do not under any circumstances pack the sliding pin holes as it causes suction which cases pads to rub on discs.

but most of all make sure that the seal recesses on the callipers are meticulously clean from 'furring (oxidisation of the alloy)' which is the cause of the calliper piston seizing in the first place.

once done i would recommend commuters and high mileage riders do it once a year, low mileage and garage kept bikes every 3 years.

my rule of thumb is for every new front tyre i do the front callipers and for every 2 new rear tyres i do the rear calliper. the wheel is off anyway so the callipers are off i might as well while i'm there. this just happens to be once a year for me.

[SV650rules]

RRG is fine for everywhere on callipers and yes btw if pads have anti squeal shims then you should never use a grease on them as well, that defeats the purpose of the shims, the shims should be dry.


anti-squeal shims are quite hard stainless and normally teflon coated, the whole idea of teflon coating is to allow pad to move relative to piston (and stop the squeal), and the hardness of shim stops the piston digging into soft steel back of brake pad and stopping it moving laterally , putting a copper or molybdenum grease between end of piston and back of pad is a good thing and if you buy OEM pads they will normally supply a sachet of moly grease for that very purpose - but they always say don't put the grease between back of pad and the shim.

I find the 'ears' that locate the pads can often be too big to fit the location slots and need a bit of filing, they should be a slightly loose fit to allow then to slide easily and apply a bit of moly or copper grease when assembling, if the lugs bind up in the slots (and sometimes corrosion can make them do this even if you are careful when fitting them) they can negate the 'self-centreing' action of the calipers and stay in contact with the disc, which can generate a lot of heat.

Here is PDF link to TRW PFG110 white silicone brake grease, it says it is suitable for everything (including slide pins and bushes) except back of pads and brake pad supports (ears), and they make a tougher moly grease for that purpose.
http://www.partinfo.co.uk/files/XZS120GB.pdf

I think the warning about silicon not to be used in metal to metal bearings is a warning not to use it in highly stressed rotary (ball and roller) bearings instead of normal grease because the film strength of silcone is lower, and it does not have the high-pressure anti-scuff additives that 'proper' grease has (RRG carries the same warning). Just like you would not put copper grease into a normal bearing because its sh!t at lubrication and is mainly an anti-seize compound.

[Bibio]

that grease is very contradictory. it says its for rubber components in contact with DOT?? brake fluid but the actual packaging states that 'do not use as a general rubber grease on hydraulic components' well ermm callipers are hydraulic components so its no use.

stick to RRG, its tried and tested for the purpose it was designed for.

dont file anything, if the part wont fit properly then return the part as its not right.

there is no need to place grease at the location tabs and especially copper grease, if you put grease there then its just a potential contamination spot that water can wash out onto your discs.

[Craig380]

This whole thread got me thinking: why don't brake calipers on cars seem to need such regular maintenance? They don't seem to be sealed or protected from the elements any better than on a bike.

For example, a few years ago I owned a Passat PD130 diesel from new, for 5 and half years and 70,000 miles. When I sold it, it still had the factory brake pads and discs, and the brake fluid had never been changed, yet the brakes never gave me a moment of worry.

Yet there's no way I'd run a bike for anywhere near that length of time with stripping the calipers and changing the fluid (I changed brake fluid on my SV shortly after buying it, as well as greasing the slide pins etc).

[Bibio]

This whole thread got me thinking: why don't brake calipers on cars seem to need such regular maintenance? They don't seem to be sealed or protected from the elements any better than on a bike.

For example, a few years ago I owned a Passat PD130 diesel from new, for 5 and half years and 70,000 miles. When I sold it, it still had the factory brake pads and discs, and the brake fluid had never been changed, yet the brakes never gave me a moment of worry.

Yet there's no way I'd run a bike for anywhere near that length of time with stripping the calipers and changing the fluid (I changed brake fluid on my SV shortly after buying it, as well as greasing the slide pins etc).

they do but due to car brakes being assisted then you dont feel it till they are completely fubar. also the pad material thickness on cars pads is massive compared to bike ones. as for the brake fluid then your average Joe has no idea, if you have ever changed out brake fluid on a car with 50+k then its as black as black can be but this does not transfer up to the rez so you never see the state of it.

[SV650rules]

that grease is very contradictory. it says its for rubber components in contact with DOT?? brake fluid but the actual packaging states that 'do not use as a general rubber grease on hydraulic components' well ermm callipers are hydraulic components so its no use.

stick to RRG, its tried and tested for the purpose it was designed for.

dont file anything, if the part wont fit properly then return the part as its not right.

there is no need to place grease at the location tabs and especially copper grease, if you put grease there then its just a potential contamination spot that water can wash out onto your discs.

It is a brake specific grease safe for DOT fluids and seals, when it states 'hydraulic systems' it means systems using petroleum based oil, which are general hydraulic systems in the broader sense. Being a brake specific grease by a well known and respected Global manufacturer I would be very surprised if it could not be used on brake cylinder seals. Lubricants are being improved all the time as better materials become available, and greases based on vegetable oils have been superseded by silicone / PTFE based compounds, which are better lubricants and have a better temperature range.

Once the tabs on the disc get tight / corroded then pads cannot move and the self-centering does not exist any more and the grease is there to keep corrosion in check. If I had taken back every pad where the tabs did not fit then I would have worn a groove back to the dealer, I always buy OEM pads and even they don't fit first time (they are just stamped out of steel plate, and have a taper as well as rough edges), they do however have a sachet of moly grease in the box for the rear of pads and the tabs. My mate who is a mechanic says it's common practice to check the tabs and remove a bit of metal so that they slide freely.

[Bibio]

i never buy OEM pads as the are wooden and carp the rear ones tend to get brittle and fall apart. Dunlop Pads (DP Brakes) are the best i have used to date.

lost count how many callipers especially SV ones i have stripped and rebuilt. when i started i done it 'old school' not knowing any better but we learn and adapt to find out what works and bring things upto date. if people were to go by the OEM manual then they would use brake fluid for the seals which as we all know is wrong but you still get people doing this and you still get people putting copper grease where it does not belong like the back of pads for instance which is still a common practice in such places as kwik-fit and the likes as that is what the so called mechanics have been taught. you also get people pumping out pistons and cleaning it with brake cleaner thinking that they are fixing a problem, you just have to look on youtube to see that. its amazing the amount of wrong advice people are given on such places as youtube but take as gospel due to not knowing any better.

my advice is based on experience.

[Blapper]

This whole thread got me thinking: why don't brake calipers on cars seem to need such regular maintenance? They don't seem to be sealed or protected from the elements any better than on a bike.

For example, a few years ago I owned a Passat PD130 diesel from new, for 5 and half years and 70,000 miles. When I sold it, it still had the factory brake pads and discs, and the brake fluid had never been changed, yet the brakes never gave me a moment of worry.

Yet there's no way I'd run a bike for anywhere near that length of time with stripping the calipers and changing the fluid (I changed brake fluid on my SV shortly after buying it, as well as greasing the slide pins etc).

I think you may be mistaken there Craig. Brake fluid change is part of the VW service schedule on my Touran, so I expect it was changed in routine service but they never told you. I have a service contract for my car and the fluid change just happens magically in the background.

Plus car calipers have had gaitors that cover the pistons for many years now so the calipers don't get the same bombardment at all.

[nutzboutbikes]

The info here got me thinking so I have been reading up on which grease we should be using when it comes to brakes.


Now the reason I use silicone and recommend it on the slid pins is because that is what the service manual (Haynes) says to use!.


RRG is not a good lubricant and should NOT be used on sliding pins, it can be used on the piston seals that is it.
Some say use brake fluid on the seals, my experience of this has never been good as the fluid absorbs water and turns into a white powder which causes the seals to stick to the pistons.


After spending an hour looking about the grease that should be used for the pins is this-
https://www.dowcorning.com/content/publishedlit/80-3507.pdf
It can be purchased here-
http://www.ebay.co.uk/itm/BRAKE-GREASE-FOR-CALIPER-PINS-IF-YOURE-USING-ANYTHING-ELSE-STOP-/252699042913?hash=item3ad6096461


After reading up I have changed my mind about using silicone on the sliders!, a tube of the above grease will shortly be in my tool box.

[Craig380]

I have a service contract for my car and the fluid change just happens magically in the background.


I didn't have a contract on the Passat, and they asked me if I wanted it done at the 2-year service (and asked again every year after that), and I said "no" ... that's how I know it was never changed ;)

[Bibio]

The info here got me thinking so I have been reading up on which grease we should be using when it comes to brakes.


Now the reason I use silicone and recommend it on the slid pins is because that is what the service manual (Haynes) says to use!.


RRG is not a good lubricant and should NOT be used on sliding pins, it can be used on the piston seals that is it.
Some say use brake fluid on the seals, my experience of this has never been good as the fluid absorbs water and turns into a white powder which causes the seals to stick to the pistons.


After spending an hour looking about the grease that should be used for the pins is this-
https://www.dowcorning.com/content/publishedlit/80-3507.pdf
It can be purchased here-
http://www.ebay.co.uk/itm/BRAKE-GREASE-FOR-CALIPER-PINS-IF-YOURE-USING-ANYTHING-ELSE-STOP-/252699042913?hash=item3ad6096461


After reading up I have changed my mind about using silicone on the sliders!, a tube of the above grease will shortly be in my tool box.

that is antifreeze mixed with soap :lol:

RRG is veg oil mixed with fumed silica (both are lubricants in their own right) with a melting point of 250-350c. as i have said its not good for high speed bearings but is good for sliding pins. i seem to remember that the veg oil is good old olive oil... Castrol R springs to mind :smt064

dont waste your money or have the hassle with different greases when one will do.

[nutzboutbikes]

Antifreeze it is however I think it is the Lithium it has added to it that makes it good for metal to metal lubrication, every thing I have read about RRG says it is not good for this type of lubrication.


how I miss the smell of Castrol R.


When it comes to brakes I don't mind spending a few pennies to have the correct product.

[Blapper]

In my experience Haynes manuals are of very limited use.

As I have to buy grease anyway, I'll go for the Dow-Corning stuff. I use their specialised products for other non-bike related jobs and have a lot of faith in them.

RRG for rubber, G-3407 for the pins, maybe a trace of copper grease for the piston/shim interface.

Anybody know if pointy calipers fit curvies?

[SV650rules]

What is not to like about Castrol-R, one whiff brings back so many memories, was based on Castor oil and is actually where the Castrol company name comes from.

[Bibio]

Anybody know if pointy calipers fit curvies?

fronts yes, rear no.

[Craig380]

By the way, are the standard factory-supplied caliper pistons made of stainless steel?

The material looked like stainless when I last gave the calipers a clean & grease ...

[Blapper]

fronts yes, rear no.

Thanks Bibio.

By the way, are the standard factory-supplied caliper pistons made of stainless steel?

The material looked like stainless when I last gave the calipers a clean & grease ...

I've just replaced a piston due to having a rush of blood to the head and using grips on it to get it out as compressed air wouldn't. I got the replacement from Wemoto is stainless, the originals are plated. The originals have a lovely radius on which makes inserting them easy, the Wemoto ones only have a sharp chamfer so requires care.

[Bibio]

bit late now but if you take the callipers off and leave the pads in then pump the front brake lever it pushes the pistons out for you ;)

[Craig380]

I got the replacement from Wemoto is stainless, the originals are plated.

Interesting, ta for that. The caliper pistons on my old 70s Suzi stroker were chrome plated (and badly pitted when I changed them), but the SV ones on mine have that dull, yellowy appearance which made me think they might be stainless.

[Blapper]

bit late now but if you take the calipers off and leave the pads in then pump the front brake lever it pushes the pistons out for you ;)

Aye Bibio, I was annoyed with myself for doing that and straight away formulated a system to free seized pistons (not that they will seize again ;-) ).

[nutzboutbikes]

its amazing the amount of wrong advice people are given on such places as youtube but take as gospel due to not knowing any better.

:smt079

[SV650rules]

:smt079

The internet is full of rubbish, biased opinions and untruths, but just like a heap of dirt it is possible to find diamonds in there, but you have to have a certain level of knowledge in the first place to know a diamond when you see it.

[Blapper]

True. Also true (but less often realised) is that you can find any answer you want to a question if you keep looking...