Anyone know anything about disc brakes?

Less compression moar aggression.

Do I understand correctly form this that normal outer is good/OK for the front but compressionless would be better for the rear brake? It is the rear I am struggling with, with the lever almost hitting the bar.

Yes, but having said that, both front and rear will benefit from compressionless.

Where can I get some of this compressionless brake housing from (on the net)?

I expect you can buy it from Ed.

You can buy it from me, the box said "compression" and "less" on it.

Where can I get some of this >compressionless brake housing

https://www.bike-components.de/de/Jagwire/Bremszugaussenhuelle-KEB-SL-p34496/

Ta

Right, disc brake novice seeking advice again.

The left hand lever (front brake) on my Shimano RS675s isn't returning back to it's normal position after braking. Is this because a) the pads have self adjusted so much due to wear or b) means they probably need bleeding?

b or something else. I assume the pistons retract normally?

Not really no, the brake is sticking if that makes sense?

Take out pads and clean caliper to see what happen.

Sound like sticky caliper.

Yeah.

If you push the pads in by hand does the lever then spring back up? Is there still pressure in the system?

Check the caliper for grit / gunge. Clean entirely, then lubricate the pistons.

Be careful if you take the pads out not to depress the lever further as you might eject the pistons.

Check the caliper for grit / gunge. Clean entirely, then lubricate the pistons.

Lubricated?

Surely prying the pads apart first before taking them off should push all the dirt off the piston before cleaning it with degreaser?

I was advised by my mentor that lubicating hydraulic piston is not a thing to do, what's your view?

The bore isn't that accurate. I believe there's a seal through which the pistons pass. This can dry out and become sticky, preventing the pistons from retracting.

Does this apply to all hydraulic system? (Much to learn I have).

As far as I know calipers have a seal on each piston - they have to, because they can't machine the piston to be such a tight fit in the bore that it's self sealing (and besides, that interface would wear away over time, unsealing!).

You can - again as far as I know - lubricate the piston slightly using the same oil that's in the brake lines. A tiny smear around the edges of the piston will do. Obviously to do this you need to expose the piston, so popping out the pads and installing the transport tool then gently squeezing the lever will do this.

Gotcha.

That's something I can do as a last resort if the piston doesn't work effectively.

Hayes cx5 Brake. Front pads newish sintered. Pad intermittently sticking on slightly (and noisily) after heavy braking. Any ideas? Cheers

Yep, brake calipers on cars have the fluid seal inside the caliper (like bike calipers have) and then a dust seal further out to stop the piston getting covered in crap. Competition car brake calipers don't have the dust seals (the calipers get hot enough that the dust seals would catch fire) like bike calipers. On my racecar my standard practice after a race weekend was to remove the pads, push the pistons out a bit, give it all a good squirt with brake cleaner and a bit of a jiggle about with a toothbrush or other similar brush, and after you've cleaned that all off add a bit of brake fluid to the sides of the pistons and put the pads back in. It was a bit of a faff, but better than piling into Paddock Hill Bend with no brakes, which I discovered was the alternative.

On Hope calipers they suggest using silicone to lubricate the pistons.

Red rubber grease is what I have always lubed car and motorcycle brake pistons with as it is rubber friendly and lasts a lot longer than brake fluid. Other greases or oils can attack the seals and make them swell. Silicone grease is probably also OK as they use it for diving equipment o-rings etc., apparently.

If I had that^ I'd use it, otherwise same fluid as in the system does the job well enough.

Thinking of getting disc brakes just for the front with 9 speed Dura Ace. Any ideas please?

Carlube Silicone Grease is a superior quality extreme temperature resistant grease which offers excellent water resiliency and corrosion protection..... Clear/Colourless grease...... The silicone based properties reduces friction and provides long lasting lubrication not found in traditional greases Carlube Silicone Grease is ideal for fitting new brake pads and protecting and lubricating all plastic and rubber parts which suffer constant friction..... Carlube Silicone Grease offers excellent coating capabilities which provides a barrier against moisture, seals out water and stops squeaks, without cracking or splitting the rubber....... USE ON :- BRAKE PADS...O RINGS....BRAKE.... CALIPERS.... SOFT TOP ROOF LEAKS..... BRAKE AND CLUTCH CABLES.... DOOR AND WINDOW RUBBER SEALS.... SPARK PLUG BOOTS.... PLASTIC PIPES... ALSO USE AROUND THE HOME AND GARDEN.... GREAT FOR USE ON BICYCLES MOTORBIKES GARDEN EQUIPMENT ETC

http://www.amazon.co.uk/Silicone-Grease-Purpose-Repellent-Carlube/dp/B006O7HTDE/ref=sr_1_1?ie=UTF8&qid=1422439759&sr=8-1&keywords=silicone+brake+grease#productDetails