dann2707 Posted October 31, 2012 Report Share Posted October 31, 2012 (edited) Helllloooo! Basically, I'm having a bit of a problem bleeding my rear hope mono trial. The brake bleeds as it should, by attaching a clear bit of pipe to the banjo bolt on the caliper, etc etc after multiple pumps, probably around 15 or so there are no major air bubbles circulating only ABSOLUTELY tiny bubbles as in like pin willy sizes however after a few pumps there were none pretty much. However, that's not the problem, once bled the brake still feels pretty gash compared to the front brake which feels crazily good, barely have to pull it for it to lock. The back still feels squishy however it does hold, but still it almost pulls to the bars. The problem is that once the brake has been bled, after around 2 mins or so massive air bubbles comes out of the banjo bolt despite it being fully nipped up, not just a few bubbles, LOADS! They are definitely coming out of the hole in the banjo bolt and not raising up the clear tube. They only come after pumping the brake. The brake THEN still stays the same, squishy as before. It would make sense if the brake has an air leak and that is where this air is coming from however why is air coming out of the bolt even though it is fully tightened? Any ideas on a fix? Me and Jaaaaase have been at it for a few hours with no solution. Thanks in advance. If I can think of any other symptoms, problems i've noticed i'll post. Edit - Worth noting i've changed all the seals, both in the caliper and lever. Edited October 31, 2012 by dann2707 Quote Link to comment Share on other sites More sharing options...
trials bros Posted October 31, 2012 Report Share Posted October 31, 2012 U have hit all the right points there Dan.Come on Lads help him out as I have scratched my head until it hurts. 1 Quote Link to comment Share on other sites More sharing options...
dezmtber Posted October 31, 2012 Report Share Posted October 31, 2012 Zip tie the lever for a few hours if its got a leak it will show you where. If its not got a leak it will sqeeze the air into smaller bubbles which will flow back to the highest point in the brake system and into the resevoir and fix the brake basically. If this doesn't work then I would suggest replacing all the rubber parts and a fresh bleed. 1 Quote Link to comment Share on other sites More sharing options...
trials hoe Posted October 31, 2012 Report Share Posted October 31, 2012 is the bleed nipple letting air seep back in? have you tryed a bolt rather than the bleed nipple? (maggie slave bleed bolt things fit) when i got the pistons out of my mono mini (using a foot pump) the rubber seal poped off the top of the nipple, so some air got past it, could be worth a try. 1 Quote Link to comment Share on other sites More sharing options...
Hessy Posted October 31, 2012 Report Share Posted October 31, 2012 (edited) DANNN... Hi Couple of possible things to try that could possibly work because it sounds as though air's trapped. Knock all the hoses, caliper and lever with something, handle of a screw driver etc, this helps to dislodge any air. Make sure that when putting the top cap and diaphram on that it is rolled towards the pointy end, make sure fluid overflows so no air can get in. Another thing to try could be lowering the lever below the level of the caliper, so the air rises, make sure the bleed nipple is the highest point and only undoing the bleed nipple the minimum amount needed for flluid (and air to come out). I'm asuming all fittings are tight. I found this worked well and got air rising out of the lever, was to keep the nipple closed and with something between the pistons squeezing the lever a couple of times then continue bleeding. Final thing before 'closing' the system push the pistons flush to the caliper and make sure your calipers alined properly and your pads are centred over the disk properly (no movement from the disc when the pads contact) Jed Edited October 31, 2012 by Hessy 3 Quote Link to comment Share on other sites More sharing options...
trials bros Posted October 31, 2012 Report Share Posted October 31, 2012 Jed is Mr hope. Ur the man. Quote Link to comment Share on other sites More sharing options...
dann2707 Posted October 31, 2012 Author Report Share Posted October 31, 2012 (edited) Cheers for the replies so far! Didn't think to put the caliper higher than the lever for a few bleeds. Still though, it doesn't explain what is happening with the bleed nipple. Might give that magura fitting thing a go but it's going to be hard to see when there is no air escaping. How would it have failed though? Edited October 31, 2012 by dann2707 Quote Link to comment Share on other sites More sharing options...
trials bros Posted October 31, 2012 Report Share Posted October 31, 2012 Jed is Mr hope. Ur the man. Also dan I remember my dad doing that what dez said with the zip tie. That does work but do leave it over night. Quote Link to comment Share on other sites More sharing options...
Jake. Posted October 31, 2012 Report Share Posted October 31, 2012 The other day when I took my wheel off, when I put it back on again the brake felt very squishy and pulled back to the bars, after a minute or so of pumping the lever it was back to normal... Tried that? Quote Link to comment Share on other sites More sharing options...
trials hoe Posted October 31, 2012 Report Share Posted October 31, 2012 (edited) if your giving the maggie bolt a go, empty the system and bleed from the caliper up untill you see fluid in the lever res, nip the cover up on the res and then tighten the bolt up on the caliper end (worst case senario is a bit of fluid flows back out through the caliper) then top up the res accordingly. this worked for me when i did it with mine also giving everything a good lot of tapping help loosen up any tiny bubbles too as said above. Edited October 31, 2012 by trials hoe Quote Link to comment Share on other sites More sharing options...
dann2707 Posted October 31, 2012 Author Report Share Posted October 31, 2012 Out of interest why didn't you just do the normal method when doing the maggy bolt way? Just because you couldn't see the air coming out I guess? Quote Link to comment Share on other sites More sharing options...
trials hoe Posted October 31, 2012 Report Share Posted October 31, 2012 (edited) just seemed like the right way to do it realy,you could use clear hose on a barbed fitting too. just nip up the res cover to stop the flow when switching to the bolt. Edited October 31, 2012 by trials hoe Quote Link to comment Share on other sites More sharing options...
SamKidney Posted November 1, 2012 Report Share Posted November 1, 2012 As said, calliper above the lever with as fewer bends in the hose. To stop air flowing back in through the nipple, close it just before the lever reaches the end of its stroke. Will stop the flow as its moving out of the bleed nipple. Another method I used is to over fill the brake. I pused the pistons out, so around 3-4mm was showing, then put something between it. After bleeding, I nip everything up, and set it so any air, if any, can rise up to the lever. Following that I remove the res cap, and diaphram, and slowly push the pistons in the calliper back in. A small amount fluid will overflow from the res, and any air that has risen from the lines will escape too. Top up res uf needed, and refit diaphram, by rolling it, and then the cap. Got a rock solid bleed on.my bros rear hope that way 1 Quote Link to comment Share on other sites More sharing options...
dann2707 Posted November 1, 2012 Author Report Share Posted November 1, 2012 Any reason why the bolt is letting air in slash out despite it being nipped up? Quote Link to comment Share on other sites More sharing options...
dezmtber Posted November 1, 2012 Report Share Posted November 1, 2012 The bleed nipple or the banjo with.copper washers. If its the banjo with copper washers. You will need to try sofening the copper. Heat them up to red hot then run them under a tap to quench them. Then refit them they will seal better after that Quote Link to comment Share on other sites More sharing options...
dann2707 Posted November 1, 2012 Author Report Share Posted November 1, 2012 The bleed nipple, sorry! Quote Link to comment Share on other sites More sharing options...
dann2707 Posted November 6, 2012 Author Report Share Posted November 6, 2012 Well I've changed the bleed nipple, all the seals in the caliper and lever (although the bore cap seal from tarty is the larger version so Hope sent me one free of charge). I removed the caliper piston seals again to make sure they were completely clean underneath however there was quite a bit of dirt so I cleaned that to an immaculate condition! Also on the bore cap side piston edges (the edge that is sealed by the seal) I noticed like, what can only be described as like oxidation? So I sanded that off as carefully as I could and fit it back into the caliper, it slid in much easier whereas removing it took so much pressure! Refit everything and rebled it by fitting old pads and fitting a block of metal inbetween them so there was no caliper movement what so ever (before I placed some pliers in the caliper but it wasn't that great of a fit) and It feels absolutely amazing now, barely have to pull the brake and it locks on. So glad it's sorted! Can now ride! My rear brake feels so much better than the front and my front is incredible. Just thought i'd update incase it helps anyone in the future reading this.Oh and another thing to note, when I changed the seals in the lever, I realised I hadn't fit the copper washer and circlip for the piston properly, it was holding but wasn't properly located so the washer was moving around a bit. Not sure if that effected how it was bled though. 1 Quote Link to comment Share on other sites More sharing options...
AdamR28 Posted November 6, 2012 Report Share Posted November 6, 2012 Glad it's seemingly sorted now. If the bleed nipple was leaking previously, then that will have been your issue. although the bore cap seal from tarty is the larger version so Hope sent me one free of charge Weird, sorry about that! Which brake do you have, got a pic? Quote Link to comment Share on other sites More sharing options...
dann2707 Posted November 6, 2012 Author Report Share Posted November 6, 2012 Yup one second. Quote Link to comment Share on other sites More sharing options...
dann2707 Posted November 6, 2012 Author Report Share Posted November 6, 2012 Quote Link to comment Share on other sites More sharing options...
AdamR28 Posted November 6, 2012 Report Share Posted November 6, 2012 Cheers dude. That is really odd. Hope don't make a larger bore cap seal than the one needed for that brake Silly question, but you were trying to put it here, yeah? Quote Link to comment Share on other sites More sharing options...
dann2707 Posted November 6, 2012 Author Report Share Posted November 6, 2012 Very strange indeed haha! Well when I rang up hope asking about the weird bleed nipple thing I told them about the seal and they sent me two bore cap seals, one that fits my brake now and another slightly larger one (the same size that came in the Hope caliper and lever kit) if that makes sense.And sorry, yes, fitting it as per the pic. Basically hope sent me two different sized bore seals. Quote Link to comment Share on other sites More sharing options...
AdamR28 Posted November 6, 2012 Report Share Posted November 6, 2012 I think I see what's happened - you've got a Mono Trial seal and a Trial Zone seal from Hope. The TZ one is a slightly different size as it goes in the caliper rather than the bore cap (http://www.tartybike...zoneborecap.jpg). It's entirely possible Hope have mixed them up when we got our last lot of complete seal kits, meaning you got the wrong one from us - sorry about that. I'll get a partial refund sorted out for you! 1 Quote Link to comment Share on other sites More sharing options...
dann2707 Posted November 6, 2012 Author Report Share Posted November 6, 2012 Thank you very much. Viva la Tarty! Quote Link to comment Share on other sites More sharing options...
dezmtber Posted November 6, 2012 Report Share Posted November 6, 2012 good work, seals replaced is always good. best thing you can do for an old brake everyone should be doing this Quote Link to comment Share on other sites More sharing options...
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