Harry Muff Posted November 25, 2010 Report Share Posted November 25, 2010 Got my red rubber grease through the post so I thought I'd have a go at pushing out the pistons a bit and cleaning them... Oops. Started out OK; cleaned the back one by pumping the back pedal until I could see a clean part of the piston and went at it with brake cleaner and a tooth brush before smearing the piston with red rubber and putting it back together. Next up was the left front 4 piston Tokico. Started out cautiously as they didn't want to come out very far. With each clean they came out a bit more. Problem was, some wanted to come out more than others... Just as I thought I was at the finishing line and had a good amount of each piston showing and shiny clean, I pushed one in a bit and... you guessed it, the one next to it shot out and and made a bit of a mess on the floor. Fuck. So, no point fucking around now; the calipers might as well be drained and disconnected so I can split them and rebuild them. This is, however, (not to mention rather obviously) my first time at this and I don't know what to do. Do I need new seals and all that? Or can the ones in there be cleaned up? And just how much of a cunt is it to put fresh brake fluid in to the entire front end? And how much is all this likely to cost me? You see, the bike's due for its 12,000 mile service and I'm wondering if I should just get Doble's to pick it up and pay them to do the whole lot. I have the Haynes manual, but I've been bitten before by that. Help! Link to comment Share on other sites More sharing options...
jaycee Posted November 25, 2010 Report Share Posted November 25, 2010 Its not a hard job, just an unpleasant one, I detest the way brake fluid seems to get through even 2 pairs of gloves. Seals aren't that dear, just take your time, be methodical. The bleeding bit can be a pain in the arse sometimes though. Edited to ad: next time, put a 13mm spanner between the pistons, that way you can pump the pistons quite far out, but they will still be seated. Link to comment Share on other sites More sharing options...
Jazoli Posted November 25, 2010 Report Share Posted November 25, 2010 Its easy enough to do, bleeding can be a pain but if you push the fluid through from the caliper (with a syringe) it'll be easier to bleed. top tip for next time is to use a bit of wood in between the pistons as you push them out, that way they will all come out the same Link to comment Share on other sites More sharing options...
Harry Muff Posted November 25, 2010 Author Report Share Posted November 25, 2010 top tip for next time is to use a bit of wood in between the pistons as you push them out, that way they will all come out the same Tried that, but some of the pistons didn't want to come out so the opposite ones did instead. This meant that I could hardly see part of one, but too much of its opposite one. Link to comment Share on other sites More sharing options...
Harry Muff Posted November 25, 2010 Author Report Share Posted November 25, 2010 Just been looking at prices on Wemoto. How many seals are there? It has big ones and small ones FFS. The pistons all look the same size so what's that about. I'll have a look in the Hayne's after dinner as it's covered in the usual grease and shit. The book that is... Link to comment Share on other sites More sharing options...
Harry Muff Posted November 25, 2010 Author Report Share Posted November 25, 2010 Which side is it? I have a perfectly good spare caliper sitting in the garage, if you can't be arsed to re-do the seals in yours? Cheers for the offer mate. Everything seems ok with the calipers and pistons though so it'll just be a learning experience. Incidentally, will I need new crush washers if I'm taking the calipers off completely? Link to comment Share on other sites More sharing options...
mattyzx6r Posted November 25, 2010 Report Share Posted November 25, 2010 Incidentally, will I need new crush washers if I'm taking the calipers off completely? Im not sure if there re useable but if you need to get the bike sorted quick, just take the full lever, lines and calipers off in one peice then rebuild your calipers with the banjo + hoses still attached? I would of thought someone would offer a complete rebuild kit consisting of dust seals, fluid seals, crush washers etc? If no one does its my idea, but ill go halfs with you if you do all the work. Link to comment Share on other sites More sharing options...
gurninman Posted November 25, 2010 Report Share Posted November 25, 2010 Cheers for the offer mate. Everything seems ok with the calipers and pistons though so it'll just be a learning experience. Incidentally, will I need new crush washers if I'm taking the calipers off completely? I never replace the crush washers - being a pikey, I just re-anneal them in a hot flame.... Link to comment Share on other sites More sharing options...
Harry Muff Posted November 25, 2010 Author Report Share Posted November 25, 2010 They get slightly squashed every time you torque the banjo up, so they will eventually thin ou. They are pennies to buy, so I just chuck 'em and fit new ones. Where can I get some though the right size for a bike? I'd rather not go online as the postage will cost more than the washers. Link to comment Share on other sites More sharing options...
rsv chris Posted November 25, 2010 Report Share Posted November 25, 2010 I got a halfrauds copper washer box with over 100 various sized copper washers. some in there will do the job. Also you mention the bike has done 12k miles the seals should be in good nick, if it wasn't leaking before and the pistons are not scored/corroded, absolutely no reason not to reuse seals. Don't remove them to clean behind them as should be clean on this mileage bike. Do you ride it through the winter and salt? Or is it a mainly fair weather bike? Did the pistons come out easily? If yes to all this, carry on. A roughly 15mm socket placed inbetween pistons( layed in lenghtways) stops em popping out, stable horse door bolted! Link to comment Share on other sites More sharing options...
Harry Muff Posted November 25, 2010 Author Report Share Posted November 25, 2010 Unfortunately, I use it all year round in the shittiest of weathers. Saying that, apart from the pistons themselves being dirty and sticking, overall they seem fine. So I'm going to just push the piston back in and bleed the system and see if they leak. Why? Well, £72 to replace all the seals and fluid is why... Fuck that. Each seal and dust seal is £5.42 on Wemoto. Times that by 8 then add in fluid and the little caliper mounting seals. Then the torx bit to take them apart... I only wanted to clean them for fuck sakes! Link to comment Share on other sites More sharing options...
gurninman Posted November 26, 2010 Report Share Posted November 26, 2010 They get slightly squashed every time you torque the banjo up, so they will eventually thin ou. They are pennies to buy, so I just chuck 'em and fit new ones. When they're properly fucked, I pinch Jools's ones and make her buy new Link to comment Share on other sites More sharing options...
Evilchicken0 Posted November 26, 2010 Report Share Posted November 26, 2010 You can get the copper washers from a car parts shop in one of those "handi bits" type packs - if you can't get any let me know (before lunchtime) and try and pick some up for you. Link to comment Share on other sites More sharing options...
Harry Muff Posted November 26, 2010 Author Report Share Posted November 26, 2010 I appreciate that Boris. First thing I'm going to try though is to just get some brake fluid and simply rebleed the system. The insides of the calipers seem in good nick so I'll try that first and see what happens. Link to comment Share on other sites More sharing options...
Evilchicken0 Posted November 26, 2010 Report Share Posted November 26, 2010 I appreciate that Boris. First thing I'm going to try though is to just get some brake fluid and simply rebleed the system. The insides of the calipers seem in good nick so I'll try that first and see what happens. That should be fun for you !!! Leave the top of the reservior off and jiggle the level a little. The air bubbles will come out in the res keep doing it till you get some pressure in the system then bleed normally. This is a lot eaiser than bleeding at the caliper or master cylinder. Link to comment Share on other sites More sharing options...
Harry Muff Posted November 26, 2010 Author Report Share Posted November 26, 2010 Right then. Just got back from fucking around with it. Success. I think... Pushed all the pistons in that came out without any difficulty. Gave the pistons and calipers a good scrub. Then I squeezed them all out again as far I could safely do it. Greased them up with red rubber. Pushed them all in. Wiped away all the excess. Put the pads back in and mounted the calipers. On to the bleeding. Bled the caliper I hadn't had any probs with first. No bubbles. Bled the second one. Lots of bubbles as expected. Slight pressure at the lever. Not good. So bled the master cylinder. Lots of bubbles and lots more pressure at the lever. Went back to do both the calipers again. Bubbles from both of them and pretty much normal pressure at the lever. Going to leave it all over night and bleed the cylinder followed by both calipers again tomorrow. And that should be that as long as the piston seals stand up ok. Next test after that will be the first ride. Keep an eye on the obituaries... Link to comment Share on other sites More sharing options...
Harry Muff Posted November 26, 2010 Author Report Share Posted November 26, 2010 I wonder if any of this will make any difference to the actual braking performance... Link to comment Share on other sites More sharing options...
Harry Muff Posted November 26, 2010 Author Report Share Posted November 26, 2010 Its worth doing for the fresh fluid alone. It's been in there for less than a year though... Link to comment Share on other sites More sharing options...
Dom Posted November 28, 2010 Report Share Posted November 28, 2010 What type of fluid is it? DOT4 or 5.1? I thought 5.1 absorbed moisture more quickly and so required changing more often? Mine is 5.1 and was put in around March - it's already looking much murkier than when fresh.... Link to comment Share on other sites More sharing options...
Evilchicken0 Posted November 28, 2010 Report Share Posted November 28, 2010 What type of fluid is it? DOT4 or 5.1? I thought 5.1 absorbed moisture more quickly and so required changing more often? Mine is 5.1 and was put in around March - it's already looking much murkier than when fresh.... Other way round, the 5.1 is synthetic so it's not hygroscopic. Link to comment Share on other sites More sharing options...
Phil Norton Posted November 28, 2010 Report Share Posted November 28, 2010 Other way round, the 5.1 is synthetic so it's not hygroscopic. Nah mate. It's the 5 that's not hygroscopic. The 5.1 has to be treated the same as DOT3 and DOT4 and changed on normal schedules, so once a year or so. Link to comment Share on other sites More sharing options...
Harry Muff Posted November 28, 2010 Author Report Share Posted November 28, 2010 Actually, I'm running 5.1. Someone on here told me that it doesn't damage your paintwork as much as 4 does. That's the only reason... I'm a clumsy bastard. Incidentally, it looks clear like water even after a year and 4,000 miles in the bike. I had a look at the bike yesterday after 24 hours standing, and the weird thing was that there was brake fluid around each bleed nipple. I gave the system a quick re-bleed starting with the top one, which had a couple of bubbles in it, followed by the front left which also had a couple of bubbles to give up. The right one was fine. I tightened them all up and put the caps back on which, incidentally, were left off over night as they were a bit fiddly to pull off the first time. I'm going to go and have a shufty in the garage and see if the nipples are wet again. Sounds rude doesn't it?! Link to comment Share on other sites More sharing options...
Evilchicken0 Posted November 28, 2010 Report Share Posted November 28, 2010 Nah mate. It's the 5 that's not hygroscopic. The 5.1 has to be treated the same as DOT3 and DOT4 and changed on normal schedules, so once a year or so. Cool - you live and learn (hopefully) Wet nipples sounds nice ... but you find they're peirced then it gets perverse. Give them a blast with some brake cleaner and it should be fine Link to comment Share on other sites More sharing options...
Phil Norton Posted November 28, 2010 Report Share Posted November 28, 2010 If you keep getting wet bleed nipples, even after checking and tightening them, then may find that the seats in the calipers are mullered from having the nipples torqued up too much. I had a second hand set that kept leaking in the same way and no amount of cleaning and tightening could sort the problem. You could try some new nipples, but if the seats are gone then it won't make any difference.... Link to comment Share on other sites More sharing options...
Phil Norton Posted November 28, 2010 Report Share Posted November 28, 2010 Edited due to double post Link to comment Share on other sites More sharing options...
Harry Muff Posted November 28, 2010 Author Report Share Posted November 28, 2010 Dry nipples! So that's a relief. Good pressure at the bar too. I'll ride it at some point, so I'll see if all of this has made any difference at all. Cheers for all your help chaps! Link to comment Share on other sites More sharing options...
kaighn80 Posted November 30, 2010 Report Share Posted November 30, 2010 Dry nipples! So that's a relief. Good pressure at the bar too. I'll ride it at some point, so I'll see if all of this has made any difference at all. Cheers for all your help chaps! dry nips! ooooh chafing! Link to comment Share on other sites More sharing options...
lorenzo Posted November 30, 2010 Report Share Posted November 30, 2010 A bit late on this one but firstly, if your pistons popped out then it probably means your seals weren't mullered and you're OK putting them back in. It's the pistons that are binding that you'll want new seals for. Secondly, on your nipples (either on the bike or on your body, it's not my chest you're fucking about with), try a bit of ptfe tape, that stuff plumbers use. It'll stop them leaking, it'll stop them seizing and it'll mean you don't have to torque them up quite as hard which in turn will minimise the risk of the threads stripping in the caliper, plus a roll will last you forever and only cost about 80p. Link to comment Share on other sites More sharing options...
lorenzo Posted December 1, 2010 Report Share Posted December 1, 2010 How does PTFE tape help stop leaks? the fluid doesnt come up the thread on the nipple, Wrong. It should could up the middle, but it actually comes up both. Link to comment Share on other sites More sharing options...
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