(06-06-20, 01:05 AM)Grahamm link Wrote: I spent an entertaining evening learning how to strip down, clean and rebuild the front brake calipers from my FZ6 and then getting a not very nice surprise...
The first problem was that, on one caliper, the smaller of the pistons would come about half way out, then, no matter what I did to block the larger one, the small one simply wouldn't shift any more.
Eventually I used a G Clamp to push it back in, kept the other one completely blocked, put something in the way of the smaller one, but so it would stop further out than it had gone before, then gave it as much pressure as I could from the bike pump I was using and, thankfully, it popped far enough out to get past whatever was making it stick.
I then "walked" them out by putting thinner blocks in front of them until they'd both got past the inner seals and I could just wiggle them out with finger pressure.
So I got everything cleaned up, new seals in place etc and started to reassemble it, but I couldn't get the pads to go back into place.
I know they were stiff when they came out, but I figured that was because they hadn't been cleaned for ages (or at all!) and they were on the sides that originally came from, because I was very careful about that, but I couldn't get them to fit back in place as they kept getting stuck.
Finally I looked up the code on the back of them and found the pads on a Russian website. It also had the details of the dimensions and some pictures of the bikes they were for.
I looked at the pictures. FJR, R6, R1, a 125... FZ6 Fazer? Nope, no FZ6 Fazer...!
So I tried looking up the dimensions for the FZ6's front brake pads...
The sizes of the ones I have are 94.0 x 41.0 x 10.0mm
The FZ6 pads are 93.8 x 40.3 x 9.8mm
So whatever Foccer put the pads on the front brakes, put the wrong damn ones on!!!
:2guns
Ok, they are literally just about 0.2mm too big and they still work because I've been using them for years, but they wouldn't go back easily.
I then spent ages carefully grinding down the ends with a Dremel, shaving a fraction of a mil off, checking the fit, taking another tiny bit off, re-checking, rinse and repeat until they fit properly into the caliper bracket.
Unfortunately I think the place that put the wrong ones on isn't in business any more (they've been on there for a while), so there's no chance of going back and giving them a bollocking
Lot more common than you think, pads being the wrong size. Most are slightly too small which lead to them twisting in the body, after a while they start wearing away the caliper body and then jam, some just jam and the pad wears to a taper.
I hope you got all I mean all the crap out of the seal rebates.
(06-06-20, 10:52 AM)Gnasher link Wrote: [quote author=Dudeofrude link=topic=6412.msg315897#msg315897 date=1591280433]
Good....means I'm not riding like a dick then ??
Oh dear, you don't have to ride like a dick not to have chicken strips, seems you're somewhat touchy about that :rolleyes your get there in time, perhaps.
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(06-06-20, 12:46 PM)Dudeofrude link Wrote: Oh dear, you don't have to ride like a dick not to have chicken strips, seems you're somewhat touchy about that :rolleyes your get there in time, perhaps.
Now what was it we used to say at a the track, oh yer "all the gear and no idea" :rollin :rollin :rollin :rollin
Three words Raw, Nerve, Hit never mind. Some people on this site nowadays are just so touchy :rolleyes bring back the good old days!
(06-06-20, 12:59 PM)Gnasher link Wrote: [quote author=Dudeofrude link=topic=6412.msg315945#msg315945 date=1591444018]
Oh dear, you don't have to ride like a dick not to have chicken strips, seems you're somewhat touchy about that :rolleyes your get there in time, perhaps.
Now what was it we used to say at a the track, oh yer "all the gear and no idea" :rollin :rollin :rollin :rollin
Three words Raw, Nerve, Hit never mind. Some people on this site nowadays are just so touchy :rolleyes bring back the good old days!
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??? Gnasher i dont know what Boris has done today to get your knickers in such a twist but chill out.
The original reply was meant as a tongue in cheek response.... hence the winky face emojis.
I really couldnt care less what you think of...well anything really so youd have a hard time hitting a nerve ??
WTF Boris has to do with it, you've lost me there :groan I haven't thought about him for days to be honest, clearly you have. :rolleyes He does have that effect on some people.
(06-06-20, 01:37 PM)Gnasher link Wrote: So was mine different sense of humour, I guess.
WTF Boris has to do with it, you've lost me there :groan I haven't thought about him for days to be honest, clearly you have. :rolleyes He does have that effect on some people.
Well I guess we will have to come to the conclusion that neither of us is very funny then ?
Have a good un ?
(06-06-20, 10:59 AM)Gnasher link Wrote: Lot more common than you think, pads being the wrong size. Most are slightly too small which lead to them twisting in the body, after a while they start wearing away the caliper body and then jam, some just jam and the pad wears to a taper.
Well one of them on one of the front calipers is substantially thinner than the other, I think because one was *very* stuck, so only one pad was actually doing the braking!
Quote:I hope you got all I mean all the crap out of the seal rebates.
I do too, although, surprisingly, the old seals were actually in very good shape, given they've been in there since new :look
The Pad Springs were a bit manky, but still working. I was thinking of getting new ones, but they were about £25 each which is absolutely ridiculous, so I put the old ones back.
There were some bits of crud on the outer edges of the pistons which, despite lots of brake cleaner and scraping with a plastic biro cap, wouldn't shift, but that's outside the bores anyway, so fortunately wouldn't affect anything.
Tomorrow I should be refitting them and using the vacuum bleeder kit to fill the system and then I might actually get to ride it again for a little trundle around the block to make sure everything works properly (after static testing first...!)
(07-06-20, 12:12 AM)Grahamm link Wrote: There were some bits of crud on the outer edges of the pistons which, despite lots of brake cleaner and scraping with a plastic biro cap, wouldn't shift, but that's outside the bores anyway, so fortunately wouldn't affect anything.
You can get this off with a piece of wet and dry. All 8 of mine had a pretty thick line around the rim but managed to get them all back to almost new.
I used a bit of 1500 wet & dry then polished them up after with some metal polish and a soft cloth to make sure they were nice a smooth
Tedious work but worth it ?
(07-06-20, 08:19 AM)Dudeofrude link Wrote: You can get this off with a piece of wet and dry. All 8 of mine had a pretty thick line around the rim but managed to get them all back to almost new.
I used a bit of 1500 wet & dry then polished them up after with some metal polish and a soft cloth to make sure they were nice a smooth
Tedious work but worth it
The pistons are nickle cadmium coated, where there's pitting/corrosion the coating has been damaged, the corrosion will spread no matter what you do. Any pitting/corrosion lower than 6/7mm from the edge will render the piston unserviceable, any pitting/corrosion that sits below the dust seal when the piston is retracted will start recorroding and cut the seal/s. This can happen within weeks of you servicing them and they'll be sticking eventually seizing.
This is another factor you should consider when using non OE pistons. The coating is microns thick, AM pistons are cheaper because the coating is thinner and softer, I've seen these AM pistons corrode just sitting in air! If you use the bike daily and ride in rain or the odd salt covered road, AM pistons will seize in quick time unless you keep them coated, even that will not stop them corroding.
This is why car brake pistons have rubber boots that cover all but the top few mm.
(07-06-20, 09:47 AM)Gnasher link Wrote: [quote author=Dudeofrude link=topic=6412.msg315980#msg315980 date=1591514344]
You can get this off with a piece of wet and dry. All 8 of mine had a pretty thick line around the rim but managed to get them all back to almost new.
I used a bit of 1500 wet & dry then polished them up after with some metal polish and a soft cloth to make sure they were nice a smooth
Tedious work but worth it
The pistons are nickle cadmium coated, where there's pitting/corrosion the coating has been damaged, the corrosion will spread no matter what you do. Any pitting/corrosion lower than 6/7mm from the edge will render the piston unserviceable, any pitting/corrosion that sits below the dust seal when the piston is retracted will start recorroding and cut the seal/s. This can happen within weeks of you servicing them and they'll be sticking eventually seizing.
This is another factor you should consider when using non OE pistons. The coating is microns thick, AM pistons are cheaper because the coating is thinner and softer, I've seen these AM pistons corrode just sitting in air! If you use the bike daily and ride in rain or the odd salt covered road, AM pistons will seize in quick time unless you keep them coated, even that will not stop them corroding.
This is why car brake pistons have rubber boots that cover all but the top few mm.
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Very true.... if its corrosion.
But I've found in most cases with the many I've done in the past it's not actually corroded it's just a very hard baked layer of brake dust. I have had some in the past where I actually had to use a dremel to get through it but once I did the actual coating of the piston was spot on.
But yeah once they have started to corrode your much better to replace them
Next time you, clean off the baked on dust as you call it, put the piston under a strong magnifying lens. What you'll find is a tiny pit in the cadmium, the dust is clinging to corrosion, as the coating is damaged. How does is get damaged, crud allowed to build up in the dust seal, crud contains grit and salt which is a crystal, over time coating is worn away.
That's why these brakes need to be rebuilt every 2years or 18k. If you're riding in all weathers I recommend you do it every year.
07-06-20, 11:34 AM (This post was last modified: 07-06-20, 11:42 AM by fazersharp.)
To my mind. That crud line mark's the max extent of the piston travel, so that crud wont be going past the seal, it's a dust seal by pushing the crud to the crud line it's doing what it is supposed to do. And as the pads wear the crud line will get further away.
But I can see an issue when new pads are fitted and the old crud line is now directly under the dust seal.
Having said that I have brought new pistons for my rear before I have started stripping it down, if the pistons are absolutely fine I will still fit the new but sell the old ones on.
I don't do rain or threat there of. dry rider only with no shame.
(07-06-20, 08:19 AM)Dudeofrude link Wrote: [quote author=Grahamm link=topic=6412.msg315977#msg315977 date=1591485124]
There were some bits of crud on the outer edges of the pistons which, despite lots of brake cleaner and scraping with a plastic biro cap, wouldn't shift, but that's outside the bores anyway, so fortunately wouldn't affect anything.
You can get this off with a piece of wet and dry.
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Well, they're back in the calipers now and I'm not going to take them apart again right now as I want to get them back on the bike and refill the system so I can test out my new braided lines :thumbup
(07-06-20, 11:14 AM)Gnasher link Wrote: Next time you, clean off the baked on dust as you call it, put the piston under a strong magnifying lens. What you'll find is a tiny pit in the cadmium, the dust is clinging to corrosion, as the coating is damaged.
The crud on mine was definitely on the surface as I checked by using the "clip" from a plastic biro cap to try and scrape it off and it was catching on the crud when I ran it across the piston.
In any case, it's outside the caliper body when the pads are in place, so it's not going to damage the seals. It probably would be even if I put new pads in, but they don't need replacing at the moment.
An excellent early morning run today. Must have been 50 odd bikes at The Chalet, which was open, as we shot past at around 8 o'clockish. I image Whiteways may have been open too judging by the number of bikes in the Arundel roundabout area. Went by Goodwood and Tangmere, before riding through East Meon, naturally stopping at Loomies. Well the petrol station next door. A few cops about including one on an unmarked bike. The blue lights being the giveaway. Fortunately not for our benefit. Took the A272 back to Cowfold, then some B road action across to the A22 and home. A short day today. Only196.8 mile, not the usual 200+ :lol
Whizz kid sitting pretty on his two wheeled stallion.
I've finally got the brake calipers cleaned and hooked up to the braided pipes, but due to feeling crap for some reason, couldn't do much more than that
Also I still need to clean the downpipes and put them back on the bike before I can put everything else back on the rear end, so it'll have to wait for another day.
I did try out a very useful technique, however...
Getting the rear wheel back on has, at times, been an absolute foccer of a job. In the past it's taken me over half an hour of swearing and cursing and trying to prop it up or hold it with my legs etc
But, recently, on Facebook, someone suggested a bloody brilliant idea: Use a ratchet strap around the rear of the bike to lift the wheel up to the right level, then pop the axle in, push it most of the way through, a little bit of wiggling to get the sprocket side in the right place and push the axle the rest of the way through, job's a good 'un :thumbup
The pipes are now back on the bike, but I didn't take a pic of that
(At some time I've *really* got to get around to trying that experiment with the effects of Autosol vs Harpic on corrosion resistance...)
