Insufficient lever travel

[Hairsy]

If you’ve had the system apart, rebuilt with second hand replacement components in place, and now you’re still getting old fluid out of the replaced components then you haven’t bled the system fully.
 

At this stage, I would remain optimistic that a thorough bleeding could solve your problems.

 

Just one question - did you replace all the copper crush washers with new?

[k3lv]

Still no joy even with the correct caliper this time ...I've bled the things every way possible, and I can still pull the lever to the bar , it's about half way when the brakes bite ....they pass an MOT brake test but , fail MOT  because the lever reserve travel . 

[Simon Davey]

You say you haven't changed the lever, but is it possible it's bent? 

If it's bent or damaged at the pivot point, it won't be noticeable. 

How far do you have to stretch your fingers to grab it? 

Can we have a picture.. 

[k3lv]

1st pic is where it sits (on number 1) 2nd pic is where pressure really starts to build 

[Simon Davey]

Blimey, I'm sorry I missed this. 

If that's where the pressure starts, it looks perfectly alright, but yes, coming back to the grip is puzzling.

I wish I could help.

[k3lv]

On 22/02/2024 at 18:37, Simon Davey said:

Blimey, I'm sorry I missed this. 

If that's where the pressure starts, it looks perfectly alright, but yes, coming back to the grip is puzzling.

I wish I could help.

Hi thanks for the reply , yeah it is puzzling indeed , the new MC rebuild kit I put in decided to die ....so that was fun , although I think the seal was a little too large so it must have snagged an tore , new MC kit went I today but still pull the lever back to the bar (easily) .......is there any difference between a 600 and 750 MC ? 

[k3lv]

Just tried vacuum bleeding ....again and still only gets to a certain point and nothing .....tried reverse bleeding but could not get the fluid in ....fresh out of ideas now .....might just search eBay for a MC 

[RideWithStyles]

just

Edited May 14, 2024 by RideWithStyles

[Simon Davey]

I just cant help feeling that it's the wrong lever.

Looking at the second picture where it starts to apply pressure, the lever has already moved the piston in quite some distance, but shouldn't it have only moved the piston a small amount?

It's like the angle of the lever isn't quite right.

Or, the wrong MC.

Edited February 28, 2024 by Simon Davey

[k3lv]

Yeah my 1st thought was maybe a 600 MC had been put on by mistake....but measured the piston at 15.8mm which is the right diameter for the 750 , the stroke is really long then it applies pressure right at the last minute.....even with the lever off and me using something else to push it in ....I'm out of ideas now.

[Simon Davey]

You've got the membrane (don't know what it's really called) under the lid of the MC?

Just can't think where the heck is that pressure disappearing off to????

[RideWithStyles]

the

Edited May 14, 2024 by RideWithStyles

[Stu]

@k3lv have you got the tociko calipers on the bike?

 

If so get rid of them! they are shockingly bad 

 

You can get a set of nissin calipers that bolt straight on and are much better 

[k3lv]

Simon , yeah got the little membrane that's in good condition no tears or holes . 

 

Ride, yeah ive double checked things like that ....it's usually something like that to catch me out , but all is good 

 

Stu, yeah it's the tokico calipers, I keep looking for nissin calipers but can never find any that will fit 

[RideWithStyles]

if 

Edited May 14, 2024 by RideWithStyles

[RideWithStyles]

those

Edited May 14, 2024 by RideWithStyles

[k3lv]

Well I took for MOT and it passed all the brake test it was just the lever travel ...as it could touch the bar , had a play today another bottle of fluid down and still the same result.......however I stuck a nut between the MC piston and the lever ,6mm was too much it made the bike very hard to push , put roughly an 8mm bolt between the lever adjustment bit and that was better but not as good as shimming the piston . Anyone else got an old srad to compare levers ? 

[husoi]

Why not drill a 2.5mm hole where the lever pushes the MC piston. make a M3 thread and insert a wee bolt.

Then you can adjust the bolt to your desired position.  

[k3lv]

43 minutes ago, husoi said:

Why not drill a 2.5mm hole where the lever pushes the MC piston. make a M3 thread and insert a wee bolt.

Then you can adjust the bolt to your desired position.  

already on it  .....but I don't own a drill bit or tap small enough , so gonna get them ordered

[Simon Davey]

That's a great idea. Just a grub screw would be perfect. 

[husoi]

3 minutes ago, k3lv said:

already on it  .....but I don't own a drill bit or tap small enough , so gonna get them ordered

I would offer my taps but not worth the distance.

[Hairsy]

Can I please suggest caution. That solution might get you the brake lever you want for now but you haven't actually identified the problem that you're solving.

 

I'd be super nervous about masking the symptom without first understanding the problem. In the list of critical functions on a bike, the front brake is pretty high up the list!

 

I'm really sorry that I can't offer any suggestions - but do be cautious.

[k3lv]

22 minutes ago, Hairsy said:

Can I please suggest caution. That solution might get you the brake lever you want for now but you haven't actually identified the problem that you're solving.

 

I'd be super nervous about masking the symptom without first understanding the problem. In the list of critical functions on a bike, the front brake is pretty high up the list!

 

I'm really sorry that I can't offer any suggestions - but do be cautious.

Yeah this is gonna be my last resort and short term fix until I can either solve the issue ....or replace the entire system

Edited February 29, 2024 by k3lv

[k3lv]

45 minutes ago, husoi said:

I would offer my taps but not worth the distance.

Would be a great ride though

[husoi]

Not the first time the friction bit of the lever gets worn enough to start to give problems.

A good inspection of both the lever and the end bit of the MC piston for extra wear should help the investigation.

 

and yes @k3lv can't go wrong with a trip to Scotland  

Edited February 29, 2024 by husoi