ozzydog Posted May 28, 2010 Share Posted May 28, 2010 Hello everyone, I am wondering if I may ask for your help again please? I noticed a problem about 8 days ago,when braking the front felt like it was grabbing at low speed and it made the bike pull to the left. Other than that they were working ok. It was already booked in for MOT the next day and was given an advisory on the front brake, the tester said one of the discs was warped but didn't know which one.I didn't get a chance to look at it till this monday due to work and a mate came over and measured the runout? on the discs and said they are not warped. I then took the pads out and found that on the right caliper one of the lower pistons was sticking slightly in the out position and so thinking this may be the problem I put some copper grease round it and gently worked it back and forth putting a large piece of metal between so the pistons didn't come to far out. This seemed to free it off so I put new pads in and replaced calipers to then find I suddenly have no pressure Since then I have bled the brakes repeatedly but can't get the pressure back only if I pump the lever and then it just goes. I made sure the level did not go down below the minimum level at any point but I can't figue out why I lost pressure in the first place. It does not appear to be leaking anywhere yet its taking in air? Also the piston is now sticking again and I have just found out that there are no seals or anything avaliable for these calipers, does this mean the seals are reusable or that if a seal goes it requires new calipers which to me sounds crazy I would be really grateful for any advise you may have as panic is now starting to set in, I am due to leave for the IOM TT in a few days and its really not looking good Many many Thanks for any help and very sorry for the long post Heather Link to comment Share on other sites More sharing options...
gstallons Posted May 28, 2010 Share Posted May 28, 2010 To get the calipers bled, I would start with the right side first. Mount or hold the bike in an upright position then gravity bleed this (r.h.side) caliper til there are no bubbles coming out of the bleeder screw. Tighten this screw then go to the left side. Repeat the process. Please maintain a full reservoir of fluid or you will take longer to do this. After you are satisfied the calipers are bled pull the brake lever until you have a good brake. You can test for a sticking caliper now by loosening the caliper mounting bolts and see which caliper is stuck. The problem will be caliper pad pins,caliper piston(s) or both. I don't know if caliper kits are available for these or not. There are only two things you can use in or on brake hydraulic components.Brake fluid or brake grease. NOTHING containing ANY petroleum products or distillates. If you own a temp. gun you can check front brake rotor temps. to see if one is hotter than the other. Do this after you are satisfied you have safely put everything back together and go for a trial run. You don't want to hear anything falling off your bike at highway speed do you? Link to comment Share on other sites More sharing options...
moscowphil Posted May 28, 2010 Share Posted May 28, 2010 Are you sure the sponginess is down to air in the system, and not because the caliper is sticking? If one side of the caliper won't move when you operate the brake, the side that will move just ends up pushing the disc away from it, so it doesn't feel solid. Have a very close look at the disc as you apply the brake - it shouldn't move sideways at all. if it does, a seized caliper is probably the problem, not an air lock. I have to say I've never re-built one of these calipers, so can't be much more help than this I'm afraid. Link to comment Share on other sites More sharing options...
GuzziMoto Posted May 28, 2010 Share Posted May 28, 2010 The seals are reusable as long as they are not leaking. It sounds like yours might be leaking. I have never tried using copper grease on caliper pistons but I have always been told the same as mentioned previously,t don't use anything but brake fluid and brake grease on anything that is internal to the system. Seals and o-rings that contain brake fluid should not touch anything other then brake fluid of brake grease. It sounds like you need to rebuild or replace that caliper. Brembo stuff is likely hard to get but that is a caliper that has been around for a while and if you can't find seals for it (try looking for them based on measurements) you should be able to find a used caliper around. Good luck. Link to comment Share on other sites More sharing options...
savagehenry Posted May 28, 2010 Share Posted May 28, 2010 Check here, just in case... www.yoyodyneti.com ...and good luck Link to comment Share on other sites More sharing options...
guzzimeister Posted May 31, 2010 Share Posted May 31, 2010 The seals are reusable as long as they are not leaking. It sounds like yours might be leaking. I have never tried using copper grease on caliper pistons but I have always been told the same as mentioned previously,t don't use anything but brake fluid and brake grease on anything that is internal to the system. Seals and o-rings that contain brake fluid should not touch anything other then brake fluid of brake grease. It sounds like you need to rebuild or replace that caliper. Brembo stuff is likely hard to get but that is a caliper that has been around for a while and if you can't find seals for it (try looking for them based on measurements) you should be able to find a used caliper around. Good luck. Hi I used to work in the brake industry. I suspect you have contaminated the seal with the grease and it is damaged. You have nothing to lose by blowing the pistons out of the caliper and soaking them all in brake fluid for 24 hours. There is a fair chance this will restore th contaminated one so long as it is not physically damaged. If it is, you wilol not get another seal from Brembo because they ceased to supply seals for calipers or master cylinders for recent product after an exepensive product liability action in the US which they lost. Apparently some twat put cheap aftermarket seals in as a repair, crashed and sued Brembo cos they didn't tell him not to do it. Another option is to measure the piston and do some research and try a seal from another barke brand. The seal is very simple, just a square section O-ring, which is made by gring a rubber tube accurately to size on a mandrel and then slitiing it into individual rings. Try your local Are or girling supplier you might be lucky. Failing all of this, plenty of calipers on Ebay but most at silly prices. Let me know how you go. Cheers Guzz Link to comment Share on other sites More sharing options...
gstallons Posted May 31, 2010 Share Posted May 31, 2010 Hi I used to work in the brake industry. I suspect you have contaminated the seal with the grease and it is damaged. You have nothing to lose by blowing the pistons out of the caliper and soaking them all in brake fluid for 24 hours. There is a fair chance this will restore th contaminated one so long as it is not physically damaged. If it is, you wilol not get another seal from Brembo because they ceased to supply seals for calipers or master cylinders for recent product after an exepensive product liability action in the US which they lost. Apparently some twat put cheap aftermarket seals in as a repair, crashed and sued Brembo cos they didn't tell him not to do it. Another option is to measure the piston and do some research and try a seal from another barke brand. The seal is very simple, just a square section O-ring, which is made by gring a rubber tube accurately to size on a mandrel and then slitiing it into individual rings. Try your local Are or girling supplier you might be lucky. Failing all of this, plenty of calipers on Ebay but most at silly prices. Let me know how you go. Cheers Guzz And what did you do in the brake industry? I'm not a smart*** I would like more input in this area and on this subject. When I am working on brake hydraulic/rubber components I use a Raybestos brake assembly fluid. Any comments? Link to comment Share on other sites More sharing options...
pasotibbs Posted June 1, 2010 Share Posted June 1, 2010 It maybe a caliper seal issue but sometimes air can become trapped in the master cylinder , slightly loosen the master cylinder banjo bolt and squeeze the lever with a rag held to catch any fluid drips(fluid or air should leak out) tighten and repeat a couple of times, then wash the area with water to avoid any fluid on paint/plastic issues !!! Don't think the V11 is too bad but on some bikes the calipers bleed best if they are held so the bleed screw is at the highest point to avoid air locks. good luck hope you make the TT ok. Link to comment Share on other sites More sharing options...
jrt Posted June 1, 2010 Share Posted June 1, 2010 I've had marginal success removing air by the old 'pump and ope/close' the bleeder valve. A vacuum bleeder works mo' betta. Link to comment Share on other sites More sharing options...
guzzimeister Posted June 3, 2010 Share Posted June 3, 2010 And what did you do in the brake industry? I'm not a smart*** I would like more input in this area and on this subject. When I am working on brake hydraulic/rubber components I use a Raybestos brake assembly fluid. Any comments? Hi since you ask, started off as a quality manager and ended up after 11 years running the specialist brake division of Continental Teves (brand name Ate), 2nd biggest brake producer globally. Any brake assembly fluid is OK, mineral oil is the killer. In the brake industry mineral oil seals as used by RR and Citroen among others are coloured bright green to avoid confusion. Happy to provide further input Guzz Link to comment Share on other sites More sharing options...
savagehenry Posted June 3, 2010 Share Posted June 3, 2010 Hi since you ask, started off as a quality manager and ended up after 11 years running the specialist brake division of Continental Teves (brand name Ate), 2nd biggest brake producer globally. Any brake assembly fluid is OK, mineral oil is the killer. In the brake industry mineral oil seals as used by RR and Citroen among others are coloured bright green to avoid confusion. Happy to provide further input Guzz So YOU are one of those faceless people who are making me look older, and go bald/gray before my time. Yes, I work on a bunch of dies for "youse guys". Link to comment Share on other sites More sharing options...
guzzimeister Posted June 3, 2010 Share Posted June 3, 2010 So YOU are one of those faceless people who are making me look older, and go bald/gray before my time. Yes, I work on a bunch of dies for "youse guys". Not me boss, I'm one of the good guys ;-)Don't work for them now anyway, but still in the bloody automotive business. Even murderers get parole after 30 years.... Link to comment Share on other sites More sharing options...
gstallons Posted June 3, 2010 Share Posted June 3, 2010 Hi since you ask, started off as a quality manager and ended up after 11 years running the specialist brake division of Continental Teves (brand name Ate), 2nd biggest brake producer globally. Any brake assembly fluid is OK, mineral oil is the killer. In the brake industry mineral oil seals as used by RR and Citroen among others are coloured bright green to avoid confusion. Happy to provide further input Guzz Feel free to blab. I trust your input. Link to comment Share on other sites More sharing options...
ozzydog Posted July 9, 2010 Author Share Posted July 9, 2010 Hello again, just want to say a big thank you to you all for your advice and give you an update. As some of you said, it wouldn't bleed as the pistons where sticking intermittently on one side of the righthand caliper, we stripped it and found that both sticking pistons were badly scored, we cleaned it all out but it was shot, mild panic then set in but by luck my friend found a caliper on ebay with about 10 minutes left to bid and won it for £15! The caliper was in good condition and so it went straight on and the brakes then bled fine and we made it over for the TT (which was brilliant ) with no further problems. However riding to work the other day I felt the front brake binding and had a quick look and it seems that 2 pistons on the other caliper are now not returning so will strip it and have a look this weekend, don't fancy our chances of getting that lucky on ebay again though. Anyway thank you again for your great advice and tips and sorry for always asking questions and not being able to give anything back thank you again Heather Link to comment Share on other sites More sharing options...
gstallons Posted July 9, 2010 Share Posted July 9, 2010 Your learning is our reward. Link to comment Share on other sites More sharing options...
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