GSXR brake caliper rebuild
Discussion
You can remove ally corrosion by polishing it (gently) with wire wool. Use a plastic scraper or something to get the wire wool into any grooves and clean off the white gunge. Wash it all with meths or brake cleaner to get the grit and metal scrapings off.
As others have said, that piston is FUBAR and needs to be renewed. You have a 150mph bike there, do you really want to ride it when the piston is chewing up the seal? OK, only when you change the pads, but come on.
Like the other poster, I was thinking about comp air but that only works on single piston brakes. If one piston is stuck then it won't work once the other piston (s) are out. You can get round this by not popping any single piston until they are all moving but this is a faff. The internal pliers will work, not had to use them myself.
Red brake grease on all the rubber sliding parts on reassembly. No oil, it rots the rubber. WD40 works short term but it's a bodge.
As others have said, that piston is FUBAR and needs to be renewed. You have a 150mph bike there, do you really want to ride it when the piston is chewing up the seal? OK, only when you change the pads, but come on.
Like the other poster, I was thinking about comp air but that only works on single piston brakes. If one piston is stuck then it won't work once the other piston (s) are out. You can get round this by not popping any single piston until they are all moving but this is a faff. The internal pliers will work, not had to use them myself.
Red brake grease on all the rubber sliding parts on reassembly. No oil, it rots the rubber. WD40 works short term but it's a bodge.
I believe WD40 is 8 parts paraffin or white spirit and 2 parts 3 in 1 oil or similar, I wouldn't let it near any brake rubber parts, try soaking an old seal in WD40 and see what happens.
Back on topic you can scrape away at alloy calipers with cocktail sticks, toothbrushes, sharpened bits of plastic etc, try scratching the caliper where it doesn't matter, if it leaves a mark, don't use it.
Brake cleaner aerosol is good and cheap enough, better than Meths we once used although you cant drink left over brake cleaner.
I often use a cheap Lidl dremel with tiny brass rotary brushes to clean out the grooves, investment less than £25, but you still need to get right into the corners with something pointed.
Now might be the time to replace your brake lines if they are old as well.
Back on topic you can scrape away at alloy calipers with cocktail sticks, toothbrushes, sharpened bits of plastic etc, try scratching the caliper where it doesn't matter, if it leaves a mark, don't use it.
Brake cleaner aerosol is good and cheap enough, better than Meths we once used although you cant drink left over brake cleaner.
I often use a cheap Lidl dremel with tiny brass rotary brushes to clean out the grooves, investment less than £25, but you still need to get right into the corners with something pointed.
Now might be the time to replace your brake lines if they are old as well.
As you say WD40 is a solvent and light oil mixture. The solvent is actually naptha, which is the lighter bit of petrol. You're dead right it will ruin rubber, as I say I've seen it used as a bodge to get an almost-ruined caliper through an MoT, but we all know that it's on a one-way trip.
For the past 33 years I have used WD40 to clean my chains, clean chain lube off the rear wheel and swing arm, I even use it after I have used brake cleaner on the seals
My track bike had done 8 thousand miles on track when I decided I had got my money's worth out of it.
The chain wasn't lifting off the sprockets and was less than half way through its adjustment .
The only brake caliper seals I have replaced in my bikes over the last 25 years were on my 32 year old. 125 which I have owned for only 18 months
I can't be arsed to argue the toss about the ingredients of WD40. But you lot are wrong.
My track bike had done 8 thousand miles on track when I decided I had got my money's worth out of it.
The chain wasn't lifting off the sprockets and was less than half way through its adjustment .
The only brake caliper seals I have replaced in my bikes over the last 25 years were on my 32 year old. 125 which I have owned for only 18 months
I can't be arsed to argue the toss about the ingredients of WD40. But you lot are wrong.
battered said:
As you say WD40 is a solvent and light oil mixture. The solvent is actually naptha, which is the lighter bit of petrol. You're dead right it will ruin rubber, as I say I've seen it used as a bodge to get an almost-ruined caliper through an MoT, but we all know that it's on a one-way trip.
"Rubber" covers a massive range of materials, some of which may be affected by WD40, many of which will not.
You generate many times higher pressure by squeezing the brake lever than a typical air compressor will produce. 170 psi won't do anything at all if a caliper piston is well stuck.
Thanks for further suggestions.
I am quite happy that most of the caliper grooves are cleaned and I don't think the little bit of corrosion will negatively effect anything. After all - the calipers were working nicely before I decided to strip them.
New pistons and seals arrived today - so I will coat seal with red grease and slot them in place. I will then put some brake fluid around piston and push them in - should they be ALL the way in or does it not really matter?
Also - whats the deal with cable tie-ing the brake lever following a brake bleed?
I am quite happy that most of the caliper grooves are cleaned and I don't think the little bit of corrosion will negatively effect anything. After all - the calipers were working nicely before I decided to strip them.
New pistons and seals arrived today - so I will coat seal with red grease and slot them in place. I will then put some brake fluid around piston and push them in - should they be ALL the way in or does it not really matter?
Also - whats the deal with cable tie-ing the brake lever following a brake bleed?
battered said:
As you say WD40 is a solvent and light oil mixture. The solvent is actually naptha, which is the lighter bit of petrol. You're dead right it will ruin rubber, as I say I've seen it used as a bodge to get an almost-ruined caliper through an MoT, but we all know that it's on a one-way trip.
If it's Naptha why does it not declare this on the MSDS? WD-40 is relatively benign, Naptha by contrast is not. It's horrible stuff. http://www.wd40.co.uk/Files/EUF0002_0017_19-01-201...
http://www.novachem.com/Product%20Documents/Naphth... (Just an example MSDS)
Also WD40 state;
"WD-40® Multi-Use Product can be used on just about everything. It is safe to use on metal, rubber, wood and plastic."
http://wd40.com/faqs
So if you can prove it damages rubber I'd advise you make a claim as they are liable as manufacturer for advising improper use.
This comes up a lot and it's b
ks, the most likely reality is the rubber seals are already damaged, the WD40 clears the grease and grit that are holding it together and it comes apart.Looking at the data sheet I would say it was a heavy naptha, the boiling point and upper and lower explosive limits tie in with this.
The other clues are the mention of C9-C11 hydrocarbons which are heavy naptha and also that it mentions naptha in the data sheet.
The Germans insist on knowing what is in hazardous products and it is claimed to be 60-80% heavy naptha. This is similar to lighter fluid for a petrol lighter.
https://en.wikipedia.org/wiki/Wd40
The other clues are the mention of C9-C11 hydrocarbons which are heavy naptha and also that it mentions naptha in the data sheet.
The Germans insist on knowing what is in hazardous products and it is claimed to be 60-80% heavy naptha. This is similar to lighter fluid for a petrol lighter.
https://en.wikipedia.org/wiki/Wd40
Biker's Nemesis said:
I am conducting my own clinical test by dropping a rubber seal into a plastic cap of WD40 at 9am this morning.
How long should I leave it there?
I took a video of it which I posted on FB.
To dissolve about 4 million years should do it.How long should I leave it there?
I took a video of it which I posted on FB.
You might need an extra memory card.
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