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Post by headcoats on Apr 10, 2020 21:31:18 GMT 1
Mine were a fecker to do (fronts) then found pistons weren't right , so had to take then all apart then start bleeding all over again Then yesterday found rear caliper bleed nipple was weeping !!!
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Post by mak595 on Apr 10, 2020 23:06:49 GMT 1
Weird thing is, on my 31k, i had the brakes done in 20 mins with no hassle, zie tied the lever again tonight, might try bleeding the calipers again tomorrow
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Post by veg on Apr 10, 2020 23:26:27 GMT 1
My ap Lockheed calliper took days to bleed they are notorious for it, forget vacuum bleeders etc it just takes time keep pumping as others have said then use cable tie or wire leave lever over night then keep repeating then when you get to the point of smashing the f**ker up with a lump hammer it’ll miraculously work, took my about 3 days. Sometimes I think theres no rhyme or reason to it. Back in Feb I fitted my new APs to the 350 and had them all bleed up and ready to go in around 20 minutes! One thing is for sure, from (most) women to brakes, persistence always overcomes resistance.. Bryan My calliper is upside down for all intents at the bottom of the anti dive so its not in a normal position its weird that seem to have a life of their own.
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Post by JonW on Apr 11, 2020 1:37:07 GMT 1
Always worth checking the joints, usually at the splitter if you have one fitted. Ive lost count of the times that shit brakes can be attributed to leaks, no matter how small, at the joints there. A nip up of the banjos and another zip tie to the bars and viola, good brakes.
So much so now that I take a bit of garage paper wipe to the front tyre now and see if it leaks overnight when cable tied to the bars. A wipe round the joints with paper also easily shows if there are any leaks there.
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Post by darboots on Apr 21, 2020 12:08:13 GMT 1
Brakes on my LC2 are being a biatch.
Completely stripped and repainted the calipers. New seal kits and stainless pistons from Powerhouse.
Front has a BN YBR125 master cylinder but just will not bleed through. Clean fluid coming from calipers. Lines and calipers tapped to release trapped air. Lever pumped in short bursts to release air. PTFE on bleed nipples. Braided lines throughout. 4 days later.... Still no brake.
Rear was also not bleeding, but found a seized master so waiting for a NOS master to be delivered.
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Post by midlifecrisisrd on Apr 21, 2020 12:44:30 GMT 1
Ybr may be too small for your master but don't think that's the prob
It doesn't matter if you thread tape the bleed nipples. If the bottom of the nipple isn't seating correctly it will vent through the hole in the middle
Have you tried forcing fluid back up the way by either pushing the pistons back or via a tube on the bleed nipple
Also crack the banjo at the master with the lever pulled in till you get some fluid out then nip back up and release the lever
Steve
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Post by darboots on Apr 21, 2020 14:50:42 GMT 1
Thanks Steve.
I am trialling the YBR master, but yes, may need to refurb the 31K master and refit that. (It looks like it's been down the road on one corner of the 31K master as the corner is ground off - so need to build it up with 'instant metal' and file it back!)
I've only breifly tried reverse filling with a syringe as the force opens up the tubing and spits fluid all over the calipers from the nipple. I imagine the nipples have to be much more 'open' to reverse fill, so will have to retry.
I will also crack teh top banjo and give that a try.
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Post by headcoats on Apr 23, 2020 7:36:23 GMT 1
Have you taken the calipers off the forks and moved them around at different angles while bleeding and tapping the caliper bodies to move bubbles?
Put a piece of thin wood between the pads so Pistons don't pop out !
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Post by darboots on Apr 23, 2020 9:34:29 GMT 1
Have you taken the calipers off the forks and moved them around at different angles while bleeding and tapping the caliper bodies to move bubbles? Put a piece of thin wood between the pads so Pistons don't pop out ! Yep, done that too.
Reverse bled them last night and all seemed to go well. Still no 'feel' at the lever, but the missus called me in to make dinner at that point! Will have another go probably tomorrow (shopping run this evening).
Also managed to get the 31K master cylinder (mostly) stripped, but how does the brake switch come out? It appears to be a press fit (no retaining screw visible), but does that unscrew in itself? Or does it unclip somehow? It's an early 31K LC2 if that makes a difference.
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Post by shergar on May 18, 2020 20:44:57 GMT 1
Get a length of clear plastic tube, fit one end on the caliper fix the other end in the master cylinder making sure it's secure and immersed in to the brake fluid within the master cylinder so you have a fully closed circuit. Release the calliper bleed nipple and pump the brake lever, top up the master cylinder as required. Used this method every time it's never failed me even with the Triumph calipers. do you have to change from one caliper to the other at some stage ? iv just tried this method on just one side i got a lot of air bubbles from the end of the hose in the master cylinder and then they seemed to stop but still no hard brake leaver also filled res up about 5 times any advice please ? ta
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Post by shergar on May 19, 2020 14:18:49 GMT 1
any help on this issue lads as i two cannot get a leaver . i have now just noticed a b.fluid drip on the under of the front left caliper seems to be coming from piston area but hard to say for deffo and also i have renewed seals and pistons all round help please .
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Post by veg on May 19, 2020 14:28:46 GMT 1
Brakes are my pet hate everyone always says oh they are easy. My ap Lockheed calipers were an absolute b*****d to do. So I always leave levers under pressure overnight wrap wire around either bars or pegs or something suitable to keep them under pressure when not working them. Secondly always have a plentiful supply of fresh fluid and hoses into the fluid from the calipers then pump unlock then lock the bleed nipple it took me 3? Days I think in total to do my front and a similar amount of time to do the rear, I tried fluid pumps, reverse bleeds, all manner of specialty equipment and ultimately what worked was the above method. Sorry I can not be more helpful but those that say they do them in minutes must be fluid gods. It’s perseverance and just when you’re at the point that the big torque wrench is going to be used to re sculpt your bodywork they seem to work.
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Post by stusco on May 19, 2020 14:38:42 GMT 1
I always bleed both calipers back and forth until no bubbles this doesn’t guarantee a lever but you know there’s no air trapped at the caliper,if it’s leaking air will get in
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Post by shergar on May 19, 2020 21:28:27 GMT 1
checked earlier and its the bleed nipple leaking when closed tight .
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Post by headcoats on May 19, 2020 21:34:15 GMT 1
Are they stainless steel aftermarket nipples as I have found out and a few others that the angle seems wrong on the taper that is supposed to seal tight
There is a seller doing titanium (looks standard angle) ones on fleabay or try standard genuine ones ?
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Post by mak595 on May 19, 2020 21:57:57 GMT 1
checked earlier and its the bleed nipple leaking when closed tight . Try a new nipple from powerhouse, they have always been good quality.....
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Post by hoist1 on May 19, 2020 22:16:21 GMT 1
A lot to read through so not sure if this mentioned anywhere, someone suggested to me years ago while bleeding and when tying the lever to the bar to not use up all the travel. Can’t remember the explanation but has always worked for me. Think it was to do with the orifice but that could just be my dirty mind.
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Post by chrisg on May 19, 2020 22:54:13 GMT 1
If everything is ok (caliper and M/C) then it can only be air in the system. Tape the lever to the bar and leave over night, as mentioned.
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Post by hoist1 on May 19, 2020 23:17:01 GMT 1
A lot to read through so not sure if this mentioned anywhere, someone suggested to me years ago while bleeding and when tying the lever to the bar to not use up all the travel. Can’t remember the explanation but has always worked for me. Think it was to do with the orifice but that could just be my dirty mind. And I only ever use the old fashioned pipe in a jam jar method.
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Post by shergar on May 20, 2020 20:43:15 GMT 1
new nipples are the next step as the ones in are s/steel . i suppose im wasting my time and all you lads time ontill i do this .
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Post by roach3 on May 20, 2020 23:44:17 GMT 1
unrelated but i remember me and a mate picking up brand new 350f1s at the same time after a couple of days both bikes front calipers started leaking at the bleed nipples went back to the dealers white city in salford and they couldnt stop em leaking. they even had a yamaha technician come up from mitsui and even he couldnt stop em leaking. both bikes had front calipers replaced under warranty.
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Post by midlifecrisisrd on May 21, 2020 8:47:15 GMT 1
new nipples are the next step as the ones in are s/steel . i suppose im wasting my time and all you lads time ontill i do this . Yes you need to make sure everything is totally air tight 👍 Steve
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Post by JonW on May 21, 2020 8:55:18 GMT 1
Take a tissue and also check for leaks round the splitter, often they weep there.
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Post by shergar on May 21, 2020 21:47:00 GMT 1
no splitter jon just straight braided lines .
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Post by shergar on Jun 2, 2020 19:18:57 GMT 1
Get a length of clear plastic tube, fit one end on the caliper fix the other end in the master cylinder making sure it's secure and immersed in to the brake fluid within the master cylinder so you have a fully closed circuit. Release the calliper bleed nipple and pump the brake lever, top up the master cylinder as required. Used this method every time it's never failed me even with the Triumph calipers. do you have to change from one caliper to the other at some stage ? iv just tried this method on just one side i got a lot of air bubbles from the end of the hose in the master cylinder and then they seemed to stop but still no hard brake leaver also filled res up about 5 times any advice please ? ta iv renewed the nipples now and using the long clear line method still no joy . iv taken the cals off and left loose i can see the calipers trying to move but slowly in and out movement but still no leaver any more advice , i hate brakes .
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Post by Deleted on Jun 2, 2020 19:34:59 GMT 1
Couple of reasons brakes don't bleed or the lever is too soft If the master cylinder isn't pumping properly, seals knackered or the piston is seized, then you won't get the air out Fluid isn't flowing out of the master cylinder, passage way blocked Not enough fluid in the reservoir, and it's sucking air Connecting pipe (reservoir to master cylinder) is sucking air. Unlikely as it's only a gravity feed. Air is trapped at Banjo bolts. These need bleeding as well as at the bleed nipples
If the master cylinder is a mis match with the calipers, e.g a single 1/4" with twin disks, it will feel soft The master cylinder is a bit rubbish, like the 350LC master cylinder or it's in need of new seals (see the 1st point) Copper washers are leaking air (unlikely but crushed copper stays crushed so use new ones) or the banjo bolt is loose. They don't have to be wound in with a scaffold pole !!!
I recently had a rear master cylinder that just wouldn't pump. The lever seem to be working fine but nothing. Closer inspection and the piston was stuck. A little heat and it freed off. A rub down with scotch bright and worked perfectly (even on the original seals). Bleed up no problem in 5 mins, using old brake lines and new washers.
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Post by chrisg on Jun 2, 2020 19:45:51 GMT 1
Are you sure everything's built back up correctly. As mentioned I had an issue with a rear MC. The little brass disc was out of place (after the seal) I managed to find this pic and rebuilt back up with no issues. Just a thought.
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Post by veg on Jun 2, 2020 19:53:22 GMT 1
If they are off the forks try tying them higher than the master cylinder then pump the lever and tie it off overnight obviously make sure you have something between the pads of a comparable size to the discs.
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Post by hoist1 on Jun 2, 2020 19:53:51 GMT 1
If air is say trapped in the calipers , try tapping with something that’s not metal like a plastic mallet or large screwdriver handle. I read somewhere recently to bleed with the pistons quite a way out, I do mine with them flush, to me it’s less capacity to trap air. And do try the partial pumping as mentioned by panzermatt plus avoiding pulling the lever back to the bar at any point.
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Post by Deleted on Jun 2, 2020 20:04:33 GMT 1
To force air out of the caliper force the pads apart. Driving the piston back into the caliper is the best way to push air out
Basically if you have to fk about and they don't bleed up in 5 to 10 mins there is something wrong. I would never spend more than 10 mins bleeding brakes, I'd start looking for what was wrong if I didn't get a firm lever in that time. I certainly wouldn't be hitting things or hanging the bike upside down overnight hoping it cured the problem
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