Excessive brake lever travel

[SKD]

I currently have Avid Exilir 1 brakes on my bike, over that past month the brake levels have been travelling much further than I like as it almost touches the handlebars.

The bike is only 4months old and I have just bled the brakes to see if that helps but nope.

I have had the wheels off due to a puncture but I can not remember if this was before or after.

Any help will be great

TIA

 

[Globalti]

Er.... could it be that the pads are just wearing? The principle with hydraulic disc brakes is that - in theory at least - the system should take up the slack as the pads wear by gradually pumping more fluid through from the reservoir to fill the space in the cylinders. Try giving the brakes a couple of really hard squeezes and releasing.

 

[rusty bearing]

Sounds like classic worn pads...The distance the calliper pistons can move is determined as a ratio between piston diameter and activating piston (master cylinder piston) diameter and stroke length, when the pads have worn past a certain point the calliper pistons cant be moved far enough to exert any pressure on the pads and disc.
Check the pads and replace if under @3mm (backing and pad material) pushing the pistons back into the calliper body with a suitable ring spanner, often 12mm. You'll almost certainly find you have brakes again...

 

[Globalti]

Not quite correct: the reason why there is a reservoir is for the very purpose I described - to fill the increasing volume of the cylinders as the pads wear. A brake master cylinder has a piston like that inside a tyre pump; under pressure it will seal against the cylinder walls when moving forwards but when it retracts brake fluid can flow past the piston from the reservoir. The slave cyclinders are an extremely tight fit in their rubber seals and normal pad movement is accommodated by the flexibility of the seals. However as the pads wear the piston will creep slowly through the seals, which is why I recommended a good hard squeeze of the lever.

Eventually the pistons will "feed" through the seals to the point where all friction material has gone and you are pressing the backing plate against your disc, which will damage it very quickly. (I once got a lift from a colleague and the first time she braked I heard the unmistakeable sound of metal on metal and advised her to get the brake pads replaced immediately. She didn't and about three months later she was late for work then turned up all upset because suddenly there had been a terrible racket and pieces of broken, worn out brake disc had dropped out from under her car!)

Al this is theory of course and the OP's brakes might be different in design or just in need of an overhaul.

 

[rusty bearing]

Quite right, just me having a senior moment. So it might be that the OP's master cyclinder piston seals are worn and not doing the job you describe?
If the bike is only 4 months old though everything should be under warranty if there's a fault

 

[SKD]

thanks chaps,

I will take a look at the pads over the weekend, it may be the pads as I have never checked but thought pads would be fine with the bike being only 4 months old, but its the first bike I have had with disc's/pads so I am unsure how long these last.

I will report my findings

 

[Cubist]

thanks chaps,

I will take a look at the pads over the weekend, it may be the pads as I have never checked but thought pads would be fine with the bike being only 4 months old, but its the first bike I have had with disc's/pads so I am unsure how long these last.

I will report my findings

There's no hard and fast rules on how long they will last. A lot depends on the conditions you ride in, with some soils far more abrasive than others. The pads on my hybrid (Avid Elixirs) lasted for a very long time, but then simply don't have the same job to do as MTB brakes rode hard.