Hydraulic brake lever question

[Richard.1]

I have two bikes both with hydraulic brakes - one Shimano and the other Sram.

I spend hours trying to get all the air out but always find the rear brake lever moves slightly further than the front. Some time ago the LBS said this was due to the longer length of hydraulic hose - so rear lever will never be quite as stiff as the front. Both bikes have no issues with stopping and the brakes seem to work fine.

I would be really interested to know if others notice this or am I just not doing the bleeding right.

 

[2old2care]

I installed my own Shimano hydraulic brake system on my road bike 2.5 years ago and I haven't needed to bleed it since. I haven't noticed any difference in my lever travel or feel.
Maybe I was just lucky, but the bleeding procedure I followed was to put the bike at an angle that would allow gravity to assist the air to rise up towards the lever where the fluid cup is screwed in and using the syringe at the caliper to force fluid and the air upwards.
Maybe you have a small leak in your system or tight bends may hamper bleeding, one reason for differing lever travel might be different pad thickness, as when the pads wear the lever travel will increase over time, so if you use your rear brake more!!!
Hope this helps

 

[Levo-Lon]

Have you adjusted the lever traval adjustment screw?
Are the calipers correctly aligned? They would be a bit noisy and some drag if wonky.
But would cause a poor feel at a lever.

I set my levers the same on all bikes as i like them even.
Little grub screw on most set ups, small allen key to adjust.

As for lbs reasoning its hydraulic so if its air free then it wont cause any delay in moving the pistons.
It may be a case of your rear pads are further away than the fronts, this could be sticky pistons, so they are retracting a fraction more after application, you could pop a feeler guage between the pads and disc to see if there's a bigger gap? So more lever traval required to apply brake.
Check lever adjustment first. As i think this will sort it.
If its the piston seals, a clean would sort that, but i doubt it's tight pistons.

 

[Yellow Saddle]

I have two bikes both with hydraulic brakes - one Shimano and the other Sram.

I spend hours trying to get all the air out but always find the rear brake lever moves slightly further than the front. Some time ago the LBS said this was due to the longer length of hydraulic hose - so rear lever will never be quite as stiff as the front. Both bikes have no issues with stopping and the brakes seem to work fine.

I would be really interested to know if others notice this or am I just not doing the bleeding right.

What you experience there is perfectly normal and your bike mechanic is correct. Longer lines produce a different feel in lever stiffness. It is particularly noticeable on tandems with hydraulic brakes where the rear line is much longer.

One way, and the only way, to test for air in the brake line is to let the bike stand for a few hours. Then approach it, straddle it and pull both brake levers hard and hold for a second. Then release and pump them. Are they getting stiffer? If yes, then there is air in. If the feel remains the same, there's no air in them.
Go for a ride, drink a beer and forget about your brakes. They are just fine.

 

[fossyant]

Just follow the instructions for a bleed - I found Epic's instructions spot on, and takes minutes if needed. There will be a slight difference in front/rear pull, but not much - can't say I've noticed much difference on stiffness though on my two hydraulic equipped MTB's SRAM and Shimano, although they are both decent brake sets, Shimano SLX and SRAM Guide RS

 

[Crankarm]

I have two bikes both with hydraulic brakes - one Shimano and the other Sram.

I spend hours trying to get all the air out but always find the rear brake lever moves slightly further than the front. Some time ago the LBS said this was due to the longer length of hydraulic hose - so rear lever will never be quite as stiff as the front. Both bikes have no issues with stopping and the brakes seem to work fine.

I would be really interested to know if others notice this or am I just not doing the bleeding right.

You need to tell us what model Shimano and SRAM disc brakes you have. There should be no air in the system whether you have cheap entry level or top of the range brakes. Better models will have adjustable brake levers to adjust the bite point, nearer or further from the handle bar. Better and generally more expensive options will have more powerful and better modulated braking. You could always fit braided hoses but tbh std plastic hosing is fine if the system is set up and bled properly. Do you have a bleed kit?

 

[SpokeyDokey]

Shimano on my Trek. These:

https://road.cc/content/review/181892-shimano-105-rs505-hydraulic-sti-road-disc-brake-set

I like both my bite points to be the same and these are easily adjustable.

Plus I can't detect any spongy-ness on either brake - not that I use the back one much.

 

[CXRAndy]

There are methods where you can take up alot of the extra travel by bleeding with pads in place. Using a piece of paper to create a wafer thin gap.

 

[Crankarm]

There are methods where you can take up alot of the extra travel by bleeding with pads in place. Using a piece of paper to create a wafer thin gap.

The brakes SHOULD be bled with the pads in place. How else are you going to stop the pistons coming out and then getting brake fluid all over the place? Why would you even try to bleed the air out without the pads in?????!!!!

 

[Richard.1]

Thanks for the replies. My Shimano is RS505 which does not have bite point adjustment (I think). I thought the adjustment is just for the lever reach.
The SRAM is Rival, both are drop bars. I have not yet looked into whether the SRAM has bite point adjustment.

Sorry, slight error in my original post - I did not mean the rear feels less stiff, I meant the lever travel is just a bit more before the biting point and also where both levers refuse to go any further.
Just to clarify - both bikes have good working brakes, there is no sponginess. Both bikes are set up with left and right reach exactly the same. For both bikes the front hardly needs to be touched (2-3mm measured at very bottom of lever) before brakes engage and less than 1 cm travel later it refuses to go any further. The rear on the other hand does not engage until around 5mm and does not stop until 1.5 cm travel later.

Pads are the same thickness.
Regarding rear pads being further away - I was under the impression hydraulic is self adjusting so would front and back not be the same distance from rotor?
I follow recommended instructions for bleeding (obviously different for Shmano and SRAM) and I have all the gear but seem to have to spend a lot longer to get the last air bubbles out compared to youtube videos. I don't bleed with pads in place, I use a bleed block.

 

[CXRAndy]

The brakes SHOULD be bled with the pads in place. How else are you going to stop the pistons coming out and then getting brake fluid all over the place? Why would you even try to bleed the air out without the pads in?????!!!!

Shimano supply a spacer to replicate the pads and gap. Unfortunately the spacer is too wide, the gap is too big, sometimes results in the brake lever travel hitting the handlebar. I and others have made a smaller spacer to reduce the gap-very effective. The problem with using pads in place is contamination during the bleeding process. I use cling film to cover the pads and a piece of paper to create the wafer thin gap. Bleed away and it results in a lever with very little travel before the bite point.

 

[Crankarm]

Shimano supply a spacer to replicate the pads and gap. Unfortunately the spacer is too wide, the gap is too big, sometimes results in the brake lever travel hitting the handlebar. I and others have made a smaller spacer to reduce the gap-very effective. The problem with using pads in place is contamination during the bleeding process. I use cling film to cover the pads and a piece of paper to create the wafer thin gap. Bleed away and it results in a lever with very little travel before the bite point.

Contamination, how? And it's not contamination it's spillage of brake fluid. I cannot see how unless you are extremely ham fisted that you can get brake fluid on the pads, discs or anywhere else. Seems like this spacer is just a gimmick that you don't need to justify selling a "kit". I have never used such a spacer whether bleeding bicycle, motorbike or car disc brakes. Bleed the brakes with the pads in and your problems will be over.

 

[derrick]

The brakes SHOULD be bled with the pads in place. How else are you going to stop the pistons coming out and then getting brake fluid all over the place? Why would you even try to bleed the air out without the pads in?????!!!!

You take pads out so they do not get contaminated with brake fluid. Plastic shims replace pads while bleeding.

 

[Crankarm]

You take pads out so they do not get contaminated with brake fluid. Plastic shims replace pads while bleeding.

You seem to have not properly read previous posts. Simply repeating "You take pads out so they do not get contaminated with brake fluid" is pointless. I suspect pads are removed because most people are pretty ham fisted and shouldn't be in charge of a knife and fork let alone servicing braking systems.

 

[derrick]

You seem to have not properly read previous posts. Simply repeating "You take pads out so they do not get contaminated with brake fluid" is pointless. I suspect pads are removed because most people are pretty ham fisted and shouldn't be in charge of a knife and fork let alone servicing braking systems.

I repeated it because some people dont listen.