I have just fitted my first set of hydraulic brakes and would like to remove one end of the brake hose to be able to route it through a cable guide that is installed to the fork. If i did this would i have to do anything like bleed the brakes and replace the fluid or just go for it and is it best to do this at the brake lever end or the caliper end?

Ta

Phil

you might get away without bleeding – remove the wheel and pump the lever GENTLY so the pistons move out but don't pop right out. Remove the hose at the lever end, route it and reconnect, push the pistons at the caliper back in which should push any air bubble back into the master cylinder. fair chance they won't need rebleeding after that.

However its well worth learning to bleed them – its not tricky and should be bled thru with new fluid every year anyway

Cheers TJ – think i'll wait until they need bleeding rather than doing it now and fooking it up 🙂

I'm sure a cable tie will do an adequate job for now.

I've never seen a cable guide like this on a set of forks. Amy chance of a photo/description?

Oh – and as for bleeding brakes every year – that must be only if you have Hopes. I have some Shimano Deores which are 5 years old and still never needed bled.

Yes Magura Phaon – guide is pre built into the lower leg.

Druidh – bleeding thru with new fluid annually is good practice as fluid deteriorates with age – not as crucial with shimano as its mineral oil which is not hydroscopic but its a part of routine servicing for any hydraulic system. Same as changing suspension oil annually or engine oil in your car.

One of the reasons why folk get problems with brakes is cos they don't do this.

check your cars service schedule – might be every two years but usually every year – its costs pennies and take 5 mins.

edit:

With use over time, brake fluid will become contaminated with dirt and moisture and should be replaced.

from http://www.parktool.com/repair/readhowto.asp?id=126

How can it become contaminated with dirt and moisture if it's a sealed system?

philsimm – Member

Yes Magura Phaon – guide is pre built into the lower leg.

Hmmm. Not sure about that. I'd rather leave it the way you have it.

be careful not to get fluid….. well, anywhere.

ruins pads
ruins rotors
ruins paint

….have fun!

Am i missing something – won't a new zip tie secure the hose?

stuey – the OP wants to put the hose through the hole in the forks (the one the zip tie is in). I'm not convinced that's what it's for.

If they're new brakes chances are you'll need to bleed them anyway, and maybe trim the hose. If they're used I'd definitely bleed them. Best investment you can make with any bleed kit is a 20ml syringe, much more control than a squeezy bottle, the flexible hose is available from pet shops (used on fish tank pumps). I'f they're hope or shimano chances are that's pretty much all you need, except a set of worn pads, some fluid (or mineral oil in the case of shimano) and some patience.

Oh iirc that hole is for bolt on magura 'firm tech' brakes – not a disc hose

Magura used to do sell little hose guides that fit the threaded hole.
I just use a couple of zip ties.

oh i see stuey 😳

Zip ties it is then

Stuey is right, it's for firm tech brakes, got some on my bike, the holes should be on both fork legs (behind the leg) which is a bit of a give-away…

Looks made for the job
I'd use it – drill it out a bit if necessary

How can it become contaminated with dirt and moisture if it's a sealed system?

Because no system is 'totally' sealed. Every time the caliper moves out and back in it can take a tiny amount of dirt with it which then gets into the fluid. There is also always a small bit of air in any system (otherwise it would be a vacuum) which will also eventually get into the fluid.

sharkbait – Member
There is also always a small bit of air in any system (otherwise it would be a vacuum) which will also eventually get into the fluid.

How can it be a vacuum if it's filled with fluid?

How can it be a vacuum if it's filled with fluid?

…….. I didn't say there was a vacuum.

You cannot guarantee to get every bit of air out of a system mainly because the fluid will have some air within it, you just can't see it.

air penetrates the hoses anyway, as does water.

iirc, dot fluid is hydrophilic, so attracts it.

i wouldnt worry, not a huge problem, just lowers the heat resistance of the fluid.