27 votes

Why did the hydraulic disc brake stop working when riding down a steep mountain?

What you experienced was brake fade. There are two reasons why it happens: The fluid inside the brake boils releasing gas into the system which makes the brakes feel spongy and then non-existant. ...
user avatar
  • 8,767
19 votes
Accepted

How do I rebuild Shimano XTR brake levers?

This answer must be prefaced with the obvious: brake-related work is high-consequence and could be genuinely injurious if performed incorrectly. Please exercise your own judgement regarding your ...
user avatar
  • 10.8k
18 votes
Accepted

V-brake vs hydraulic disk-brake - which is more environmentally friendly

We can assume that V-brake pads are essentially non-degradable. The same is true for resin disc pads. But are non-recyclable. Metal disc pads seem to be various copper alloys which are probably OK ...
user avatar
  • 46.2k
16 votes

How to install pre bled brakes with internally routed frame

Usually what you do is disconnect it at the lever, install the lever to the bar, and run the hose up from the caliper end. Because it's sealed on the other end, no more than a few drops of fluid will ...
user avatar
16 votes
Accepted

Is there way to fix a disc brake rotor if slightly bent?

Yes. Disc brake rotors can warp a little in use, or get bent from impacts and straightening them is routine maintenance. The basic procedure is to find spots where the rotor is bent inboard or ...
user avatar
16 votes

Is this bike suitable for a male

The Older Paradigm of Women's Specific Bikes Argenti and Kaz both are correct, but let's dive a bit deeper into women's specific design (WSD). Their answers allude to an old paradigm of WSD. It ...
user avatar
  • 19.3k
15 votes

Does this bike use hydraulic brakes?

If there are no signs of a metallic wire (often colored silver) exposed anywhere near either end of the black housing "tube" connecting the lever on the handlebars and the caliper on the fork, it ...
user avatar
15 votes
Accepted

What is this stamped metal piece that fell out of a new hydraulic shifter?

Providing the 7900 is the same, I’m sure it is but someone more qualified can chip in if it’s different. How did it fall out ? Shimano have a proper tool for removing them. Info from here Fawkes
user avatar
  • 1,078
13 votes

Hydraulic Vs. Mechanical disc brakes

Cable discs rule if you are riding a lot of third world. I am a million miles away from a shop, access to the oil, etc. A hydraulic failure would be disaster, whereas the worst thing that will happen ...
user avatar
  • 131
12 votes

Can hydraulic brake levers get hot when brakes overheat?

No, the thermal conductivity of brake hose/fluid is way too low. I've run the numbers on this -- very roughly to make the calculations simpler. I've assumed the hose isn't cooled by airflow for some ...
user avatar
  • 46.2k
12 votes
Accepted

What causes and how to fix wandering bite point on Shimano hydraulic brakes?

Originally I gave a tentative answer to this question and proposed the solution without actually trying it (next three paragraphs), and now that I have tried it I expand the answer with a report on ...
user avatar
  • 656
12 votes

V-brake vs hydraulic disk-brake - which is more environmentally friendly

The world is full of perfectly good cantis, v-brakes, and rim brake wheels that sit unused since disc has taken over. Using what we've already produced for its actual full service life is pretty hard ...
user avatar
11 votes
Accepted

why can't you use park tool shift cable cutter to cut hydraulic cable

The comments OraNob and Batman said are spot on. A cable cutter uses shear force (focused crushing) to cut through the metal wound wires in a cable housing but still requires some clean up because of ...
user avatar
  • 9,051
11 votes

Can broken caliper be fixed?

I highly doubt you'll be able to find a separate alloy casting to replace the one that broke. Even if you can you'll be faced with assembling the caliper which is not trivial. Just buy a replacement ...
user avatar
11 votes

V-brake vs hydraulic disk-brake - which is more environmentally friendly

The true answer is: It really doesn't matter. You are riding a bicycle, that is what matters. If you are truly eager to minimize your ecological footprint, caring about the break type on your bike is ...
user avatar
10 votes

How do I get my hydraulic disc brakes working well again

Most likely cause if the disc and pads are contaminated. What did you wash it with? Many cleaners leave a residue. Worst case the pads need replacing. The discs should be well cleaned before ...
user avatar
  • 40k
10 votes

How can I reset hydraulic brake pistons without removing the wheel?

I believe it is not worth trying it. You risk contaminating, scratching, or bending your rotors, as well as scratching or cracking a brake pad. Consider also whether there are bigger problems with ...
user avatar
  • 1,326
10 votes

Disc Brakes *Completely* Ineffective

I've had my fair share of hydraulic brake woes this year so I'll list the things I'd check - I am aware that you've done some already. Firstly some questions though: Are these brakes using mineral ...
user avatar
  • 809
10 votes
Accepted

Is it safe to run disc brakes up front on a mountain bike that lacks a disc caliper mounting point in the rear?

A few years ago this was a reasonably common setup as sold. I've certainly ridden an e-bike set up that way, with v-brakes at the back and a mechanical disc brake at the front. I suspect this wasn't ...
user avatar
  • 46.2k
10 votes

Brake disc sometimes touching brake pad when not braking

Rotors can and do bend, subtly. Have you checked it's flat? One of mine sounds flat (or rather doesn't sound) cold, but has a high enough spot when hot to sing. Have you checked for play in your ...
user avatar
  • 46.2k
9 votes

Can storing bicycles upside-down damage hydraulic brakes?

From Shimano Service Instructions: When turning the bicycle upside down or on its side the brake system may have some air bubbles inside the reservoir tank which are still there when the ...
user avatar
  • 11.7k
9 votes
Accepted

Converting road hydraulic disc brakes to flat bar : Possible?

The official answer from Shimano as of now is no, as per their road hydraulic systems compatibility chart. Someday there may be flatbar road hydraulic levers that make their way onto a new version of ...
user avatar
9 votes
Accepted

Are disc brakes weak? And what is "bedding in"?

Bedding-in is a common process with new disc brake pads. Disc brakes were developed much earlier for motorcycles and cars, from which the technology and the terminology has been transferred to MTBs: ...
user avatar
9 votes
Accepted

Brand new bike. Briefly removed the rear disc brake caliper, now it's too tight

As mentioned in comments you most likely applied the brake without the disc between the pads. The pistons advance and do not return all the way to their original position - this is how hydraulic ...
user avatar
9 votes

Why are brake levers still bent in form to accomodate more than one finger?

TL;DNR - single finger levers have little (if any) advanatage and some disadvantages. Most people do not start out cycling with XT/Ultegra quality bikes and therefore (do not) start out on bikes ...
user avatar
  • 40k
9 votes
Accepted

Pros and cons of mixed hydraulic/mechanical brakes vs pure hydraulics

Background For most of cycling history, we've actuated derailleurs and brakes by pulling cables. One of the possible disadvantages of cables in general is that as the cable housing exerts a bit of ...
user avatar
  • 19.3k
9 votes

Can broken caliper be fixed?

It is a brake - a critical safety component. Just replace it. Any fix or hack or bodge could fail you at the worst moment, endangering you and others around you. This one has already broken, who's ...
user avatar
  • 99.1k
9 votes
Accepted

Shimano Deore hydraulic brake problem

The part that popped out is one of the pistons. There should always be a bleed block in place between the pistons when bleeding the brake. Immobilizing them this way is what prevents overfill and also ...
user avatar
9 votes

Heating of hydraulic oil with hardtail electric MTB brakes

pumping worked to no avail-which usually works This is ringing alarm bells for me - it implies you encounter brake fade on a semi regular basis. This is almost certainly down to poor braking ...
user avatar
  • 14.5k
8 votes
Accepted

How do I tell the size of my braking discs?

The disc that you are talking about is in fact called the rotor. Rotor size is measured by diameter, ie. edge to edge through the centre. The size may also be etched on to the rotor which would be ...
user avatar
  • 8,767

Only top scored, non community-wiki answers of a minimum length are eligible