Wallie Posted April 27, 2014 Report Share Posted April 27, 2014 So i swapped out the lines on the 636 for some new stainless ones. No issue with installing them, apart from I can feel the lever pressure increase whenever you put some heat into the discs. The lever just goes ultra sensitive but returns to normal after a taking it easy for a mile or two. I have rebled both calipers and the m/c, all with fresh fluid and have no air bubbles. Any idea's as im stumped? Link to comment Share on other sites More sharing options...
gsxr renegade Posted April 27, 2014 Report Share Posted April 27, 2014 Too much fluid in the reservoir? Link to comment Share on other sites More sharing options...
Wallie Posted April 27, 2014 Author Report Share Posted April 27, 2014 Already checked, its in the middle of the upper and lower level. Link to comment Share on other sites More sharing options...
kaighn80 Posted April 27, 2014 Report Share Posted April 27, 2014 What grade of fluid are you using? Link to comment Share on other sites More sharing options...
Enzo200500 Posted April 27, 2014 Report Share Posted April 27, 2014 Do you have aftermarket levers? I shimmed out the lever on my RG500 to improve the standard lever pressure. Worked like a dream until 6 miles down the road and the front started to seize up. Turns out the pads were just rubbing enough to generate lots of heat and you could actually feel the pressure building on the lever! Wheel turned fine when stone cold in the garage. Cue roadside strip of front brake lever, problem solved! Link to comment Share on other sites More sharing options...
Wallie Posted April 27, 2014 Author Report Share Posted April 27, 2014 What grade of fluid are you using? Dot 4. Was given for free when i brought the lines. Do you have aftermarket levers? I shimmed out the lever on my RG500 to improve the standard lever pressure. Worked like a dream until 6 miles down the road and the front started to seize up. Turns out the pads were just rubbing enough to generate lots of heat and you could actually feel the pressure building on the lever! Wheel turned fine when stone cold in the garage. Cue roadside strip of front brake lever, problem solved! I've heard of that before but I have standard lever fitted! Link to comment Share on other sites More sharing options...
Rich Posted April 27, 2014 Report Share Posted April 27, 2014 Do you have aftermarket levers? I shimmed out the lever on my RG500 to improve the standard lever pressure. Worked like a dream until 6 miles down the road and the front started to seize up. Turns out the pads were just rubbing enough to generate lots of heat and you could actually feel the pressure building on the lever! Wheel turned fine when stone cold in the garage. Cue roadside strip of front brake lever, problem solved! It's not heat that directly causes this, it's the fluid return hole in the master cylinder being covered due to the piston not returning fully. Some aftermarket levers can cause this, as can not having enough free play at the lever (same difference). It will freewheel when cold but as the fluid warms up and expands the pads will jam on due to having no return to the reservoir. This is why it's so important to have a small amount of play between lever and piston as the consequences can sometimes be very nasty! Link to comment Share on other sites More sharing options...
Wallie Posted April 27, 2014 Author Report Share Posted April 27, 2014 You've still got air in the system, probably in the m/c. Ill have another at bleeding it, but when i did it the other day it was pure fluid that was coming out. Is there a better way of bleeding it apart from the usual pipe into a jar method to get stubborn air out? Link to comment Share on other sites More sharing options...
lorenzo Posted April 27, 2014 Report Share Posted April 27, 2014 Try putting either the caliper or the master cylinder as a funny angle so that the bit you're bleeding is at the highest point. Also, push the pads back into the caliper, you can get air trapped behind the pistons. Link to comment Share on other sites More sharing options...
kaighn80 Posted April 27, 2014 Report Share Posted April 27, 2014 If your not getting any more air out get a zip tie, pump the shit out of the lever so it's pumped right up then zip tie the lever back to the bar, walk away and leave it over night, next day cut the tie. Any air that was in the system will now hopefully have floated back up the line and be waiting in the master cylinder to be released into the reservoir. Worked for me loads of times. Link to comment Share on other sites More sharing options...
Wallie Posted June 10, 2014 Author Report Share Posted June 10, 2014 So bit of an update, not really had chance to use it so only just got around to sorting it. I have tried using the zip tie overnight trick, flushed the master cylinder through multiple times and tried bleeding the master cylinder at the highest point as well as both calipers. But get any sort of heat back into it and you can feel that there's too much pressure in the system. There is absolutely no air in the system, it is coming out pure fluid. Im thinking either its in my head or a duff master cylinder. I've got to go 200 miles back to Wales tomorrow so im going to take it easy and see how it fairs. Link to comment Share on other sites More sharing options...
Wallie Posted June 14, 2014 Author Report Share Posted June 14, 2014 Bump. Link to comment Share on other sites More sharing options...
Guest Posted June 14, 2014 Report Share Posted June 14, 2014 I fucking hate bleeding brakes, this post is bought to you by no help at all, and pointless post sorry. Link to comment Share on other sites More sharing options...
BudgetBoy Posted June 14, 2014 Report Share Posted June 14, 2014 Pressure seals in the calipers or MC getting past it. (provided you have no air trapped anywhere) Link to comment Share on other sites More sharing options...
Wallie Posted June 14, 2014 Author Report Share Posted June 14, 2014 I fucking hate bleeding brakes, this post is bought to you by no help at all, and pointless post sorry. Its easily the worst job to do on bikes, i hate it. Pressure seals in the calipers or MC getting past it. (provided you have no air trapped anywhere) Thanks mate. Im going to strip it and rebleed with completely fresh fluid in the week and then look at those. I thinking it wouldn't be anything in the callipers as it seemed to be fine with the old lines (albeit lacking in bite). Link to comment Share on other sites More sharing options...
Guest Posted June 14, 2014 Report Share Posted June 14, 2014 That and the fact braided lines are not the bolt of lightning they are touted to be... Totally agree, a properly rebuilt set of calipers, correctly matched master cylinder, and good pads with fresh fluid will make night and day difference. I only ever buy braded lines as they are cheaper than buyin OEM ones. Link to comment Share on other sites More sharing options...
Wallie Posted June 14, 2014 Author Report Share Posted June 14, 2014 Make sure all the joints are TIGHT. Or better, torqued to spec. Anytime I have ever had issues with lever sponge that's what I found. That and the fact braided lines are not the bolt of lightning they are touted to be... I wasn't expecting miracles, i just wanted the lever firming up slightly. Just a thought, could over tightening create too much pressure? I left my torque wrench at home so just tightened everything it as tight as it would go (I know a tit move). Link to comment Share on other sites More sharing options...
Wallie Posted June 14, 2014 Author Report Share Posted June 14, 2014 To be clear, are you saying that the brake lever is firm with the brakes cold and that when the brakes heat up the lever gets firmer or doesn't come back as far? If this is the case then I can only think of 3 reasons as to why this could be; 1.) Air in the brake fluid 2.) Water in the brake fluid 3.) The master cylinder piston is too far down the bore with the brakes released and not allowing the brake fluid to escape up into the reservoir as it heats up. 1 and 2 can be solved by fresh decent fluid from a brand new unopened bottle and proper bleeding. 3 can be investigated by looking at the fluid level in the reservoir as the brake lever is pumped - does it bounce up and down in time with the lever? When cold the lever feels fine. Any heat and the lever firms up becomes too firm and feels over sensitive. The problem is when it cools down the pressure drops aswell and it suddenly the lever will return to the bar. The bikes been outside all morning and the fluid has heated up in the sun so feels really firm. The fluid level doesnt move at all with the lever so you may be right about with the m/c. Link to comment Share on other sites More sharing options...
Wallie Posted June 14, 2014 Author Report Share Posted June 14, 2014 Is the hose from the reservoir to the master cylinder kinked by any chance? No kink at all. Link to comment Share on other sites More sharing options...
Wallie Posted June 14, 2014 Author Report Share Posted June 14, 2014 Right cap off and the the bleed nipple open a negligable amount of fluid came out but no sort of flow, or did you mean completely remove the nipple? I did slightly pull in the lever and fluid came out but there was no real drop in m/c level that you would expect. This has also relieved the 'extra' pressure and it feels like a normal lever now. Link to comment Share on other sites More sharing options...
Wallie Posted June 14, 2014 Author Report Share Posted June 14, 2014 That tells me your master cylinder piston is too far down the bore of the master cylinder and is blocking the reservoir port (called the "bleed port" in the diagram below) from the rest off the system - or something else might be blocking the port.... With the brakes off the master cylinder should be in this state... ..so if you were to take the reservoir cap off at the top and open a bleed nipple at the bottom fluid should come out of the bleed nipple at fair rate because of the head from the fluid in the reservoir (think a water tank in your loft and opening a tap downstairs). Right that makes sense, thanks for that. So its looking like a either a rebuild or new master cylinder. Link to comment Share on other sites More sharing options...
Rich Posted June 14, 2014 Report Share Posted June 14, 2014 Check you have enough free play between the lever and end of the master cylinder piston. Link to comment Share on other sites More sharing options...
Farmfab01 Posted June 14, 2014 Report Share Posted June 14, 2014 This is the same as millemille has just said, but - some Triumph's had this problem on the other forum I go onto & it was traced down to there not being enough room on the brake lever to allow the piston to come back far enough, the solution was to file/emmery a little off the lever until there was a small gap between the lever & piston. Is your lever moving smoothly or binding & not letting the lever return fully? Link to comment Share on other sites More sharing options...
Farmfab01 Posted June 14, 2014 Report Share Posted June 14, 2014 This is off topic I know but, my mate had a braided brake line made up for his proddy TZR125 at the local bike shop, he tried for ages & ages to get it bled up, in the end he got me to have a look, & after a while I decided to blow it out with an airline & out flew a small bit of white paper towel/tissue, now how did that in there? we never found out Link to comment Share on other sites More sharing options...
Wallie Posted June 14, 2014 Author Report Share Posted June 14, 2014 This is the same as millemille has just said, but - some Triumph's had this problem on the other forum I go onto & it was traced down to there not being enough room on the brake lever to allow the piston to come back far enough, the solution was to file/emmery a little off the lever until there was a small gap between the lever & piston. Is your lever moving smoothly or binding & not letting the lever return fully? Lever moves smoothly now but did occasionally 'click' before. Check you have enough free play between the lever and end of the master cylinder piston. How would I check this? I've just had a look and I cant seem to tell from just looking. Possibly, but it's a bit of a coincidence that at the same as changing the brake lines the m/c has become u/s. Is it possible you've pulled some shit down from the reservoir into the m/c when the brake system was drained to change the lines and this is blocking the "bleed port"? EDIT TO ADD: you did remove the bladder as well the reservoir lid when you cracked the bleed nipple didn't you? The other question is how did you bleed the m/c to get all the air out of it? Yes I removed everything from the m/c. Im starting to think there was an issue to with the m/c all along, as it seemed to be fading and would occasionally click when you let the lever out. Im wondering if something has happened with the m/c piston. Jar of fluid with the the bleed valve thing (technical i know), open the nipple and pump the lever a few times, keep the lever in and close the valve. I also tried the other way of only pumping the lever once and holding it in for 30 seconds. It how i have always bleed everything and not had an issue before. Link to comment Share on other sites More sharing options...
Wallie Posted June 14, 2014 Author Report Share Posted June 14, 2014 The m/c has its own bleed nipple. I started at the furthest point being the left calliper, right calliper then the master cylinder. Link to comment Share on other sites More sharing options...
Wallie Posted June 14, 2014 Author Report Share Posted June 14, 2014 2006, its the C1H. Link to comment Share on other sites More sharing options...
blow_away Posted June 14, 2014 Report Share Posted June 14, 2014 It's possible that with all the manual brake bleeding, the master cylinder seals that might have been marginal on an 8 year old bike were worn out? Anyway, now you have an excuse to buy the Brembo master cylinder you've had your eye on Link to comment Share on other sites More sharing options...
Wallie Posted June 14, 2014 Author Report Share Posted June 14, 2014 This is the fiche for your master cylinder If you take the lever blade off and look up inside the master cylinder at the piston (item 43020), it should be pushed as far out of the body as possible and be hard up against the internal circlip (item 92033). If this is correct put the lever back on and see if the piston is being pushed further up into the bore by the lever even in the off position. Thanks, the help really is appreciated. I'll take the lever off first thing in the morning and check. It's possible that with all the manual brake bleeding, the master cylinder seals that might have been marginal on an 8 year old bike were worn out? Anyway, now you have an excuse to buy the Brembo master cylinder you've had your eye on Don't tempt me, im already watching an Accossato m/c on ebay aha. Link to comment Share on other sites More sharing options...
Wallie Posted June 15, 2014 Author Report Share Posted June 15, 2014 This is the fiche for your master cylinder If you take the lever blade off and look up inside the master cylinder at the piston (item 43020), it should be pushed as far out of the body as possible and be hard up against the internal circlip (item 92033). If this is correct put the lever back on and see if the piston is being pushed further up into the bore by the lever even in the off position. The m/c piston is flush against the circlip with the lever off. Its exactly what you say, when you put the lever back in position it pushes the piston further into the bore without touching the lever. Link to comment Share on other sites More sharing options...
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