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LM2 rear brake travel

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Ianboydsnr View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Ianboydsnr Quote  Post ReplyReply Direct Link To This Post Posted: 02 Feb 2015 at 11:08
Originally posted by Lemon 2 Lemon 2 wrote:

Would be tempted to drill that little critter out Ian, using the centre of the broken bleed screw ( which appears to be obstructed at the moment) a series of small drills taking it out to just under the thread inner diameter and not so deep as to damage the tapered sealing area of the caliper, some releasing fluid and small screwdriver or file tang the remains should unscrew.

I don't intend to do anything, until such a time as is necessary, it works fine at the moment, then I will drill a hole in it, then hammer in a splined socket, using heat around the area, and hopefully undo, if that fails, I will mill it out, possibly to M7, and tap it to take a bleed screw! Wink
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Lemon 2 View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Lemon 2 Quote  Post ReplyReply Direct Link To This Post Posted: 02 Feb 2015 at 11:25
Soz fella, teaching an old dog to do new tricks and that .
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Ianboydsnr View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Ianboydsnr Quote  Post ReplyReply Direct Link To This Post Posted: 02 Feb 2015 at 12:22
Originally posted by Lemon 2 Lemon 2 wrote:

Soz fella, teaching an old dog to do new tricks and that .

No need to be sorry fella, posts are seen by old dogs and new dogs alike, it all contributes to the knowledge held by the forum!Wink
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Tim Stanbridge Quote  Post ReplyReply Direct Link To This Post Posted: 18 Apr 2015 at 21:19
Hi, I'm back. Have only just returned to this problem after a heavy two months' workload 
'Have renewed the M/cyl seals, etc today with an overhaul kit from Gutsibits and I am, as I write with one hand on the iPhone, fruitlessly bleeding the system without much success. 
BUT.....have not tried the reverse caliper-to-M/cyl method yet.
Also, has anyone tried the vacuum-sucking-from-the-caliper-bleed-nipple with one of those kits? I got one for the Hillman Imp a few years ago but I eventually gave up using it in favour of the 8 year old son on the brake pedal-me on the spanner combo.
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Pigford View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Pigford Quote  Post ReplyReply Direct Link To This Post Posted: 19 Apr 2015 at 10:05
Broken bleed nipples are a common issue - just had fun with the rear caliper on my LM2 Confused  I had to replace the bit of steel pipe as it split at the caliper union - so used some Goodrich braided hose.

Tried drilling the nipple out as it was fused into place! On the pillar drill okay, but the dodgy bit is cleaning out the last bit at the bottom, where it seats! Gave up in the end & loctited a short s/s M6 bolt in it to ensure it wouldn't leak.

Carefully bled it with caliper high as possible and it seems okay - or at least as good as it was before.


Edited by Pigford - 19 Apr 2015 at 10:07
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Tim Stanbridge View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Tim Stanbridge Quote  Post ReplyReply Direct Link To This Post Posted: 20 Apr 2015 at 21:08
LATEST NEWS!!

Bled the system yesterday with the vacuum pump method - drawing the fluid through the system from the F/L bleed nipple, then the rear bleed nipple (fitted an integrated banjo/bleed nipple from Gutsibits).
Got a firmish pedal.....which was nice...... then tried the old bunge-cord-holding-the-brake-pedal-down-overnight-trick . Result - unbelievably hard pedal!! But......still quite a lot of travel. 
Still it's a heap better than before and it now has an MoT!
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Mike H View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Mike H Quote  Post ReplyReply Direct Link To This Post Posted: 21 Apr 2015 at 14:33
What's this business with the double banjos on the back of the M/C?
"Chicken nuggets don't dance on a Tuesday."
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Jerry atric Quote  Post ReplyReply Direct Link To This Post Posted: 21 Apr 2015 at 15:50
More to the point, what's the trick with the bungee? Never heard of it, does it just slowly release tiny bubbles in the fluid? Serious question.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Pigford Quote  Post ReplyReply Direct Link To This Post Posted: 21 Apr 2015 at 18:32
Originally posted by Jerry atric Jerry atric wrote:

More to the point, what's the trick with the bungee? Never heard of it, does it just slowly release tiny bubbles in the fluid? Serious question.


It holds the passageways open so any air can find its way out Wink
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Mike H View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Mike H Quote  Post ReplyReply Direct Link To This Post Posted: 22 Apr 2015 at 00:35
I would have thought the exact opposite. With the piston permanently depressed, channel(s) to the reservoir are closed off.
  

"Chicken nuggets don't dance on a Tuesday."
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Mike H View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Mike H Quote  Post ReplyReply Direct Link To This Post Posted: 22 Apr 2015 at 00:41
Originally posted by Tim Stanbridge Tim Stanbridge wrote:

Waaaaaaayyyyyy too much travel on the rear brake. Front brake is fine and the original dual line system has been retained.
Has anyone a list of faults that I can use to solve this problem. My first thought is dodgy fluid in the rear part of the system.....
Thanks

 
Have you by any chance fitted new brake pads or have otherwise disturbed the caliper pistons?
 
Excessive pedal/lever travel can often be attributed to pads needing to bed in and caliper pistons settle. (I have experienced this with cars too.) After some use, this happens and the 'feel' at the pedal or lever hardens up noticebly and the travel shortens.
 
HTH

"Chicken nuggets don't dance on a Tuesday."
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Tim Stanbridge View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Tim Stanbridge Quote  Post ReplyReply Direct Link To This Post Posted: 05 May 2015 at 21:33
Originally posted by Mike H Mike H wrote:

Originally posted by Tim Stanbridge Tim Stanbridge wrote:

Waaaaaaayyyyyy too much travel on the rear brake. Front brake is fine and the original dual line system has been retained.
Has anyone a list of faults that I can use to solve this problem. My first thought is dodgy fluid in the rear part of the system.....
Thanks

 
Have you by any chance fitted new brake pads or have otherwise disturbed the caliper pistons?
 
Excessive pedal/lever travel can often be attributed to pads needing to bed in and caliper pistons settle. (I have experienced this with cars too.) After some use, this happens and the 'feel' at the pedal or lever hardens up noticebly and the travel shortens.
 
HTH


Well, I got this tip (the bungee chord trick) from somewhere on this forum and it has worked. If it has challenged physics law, I'm not too bothered either way. - I've got my MoT ;)
Anyway........how did we get here?
1. took bike for Mot in February - failed on a spongy rear pedal
2. tried bleeding the brakes conventionally - no better, in fact a lot worse.
3. bought a new Brembo overhaul kit - still no better
4. used a vacuum pump to draw brake fluid through the system from the M/C - good pedal.
5. bungee chord trick for a week = rock hard pedal
6. MoT pass - TT 1st week here we come!



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Ken-Guzzibear View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Ken-Guzzibear Quote  Post ReplyReply Direct Link To This Post Posted: 05 May 2015 at 21:40
reverse fill has always worked I learned this yrs ago got help from a Guzzi mechanic he told me the old Brembo calipers often get air trapped behind them ... takes under 1 min each brake caliper The ONLY  time this did not work the mast cyl was knackered it was a new one
The Older i Get, The Better I Was
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