How long should hydraulic brakes last?

[ichitan]

My new bike has hydraulic disc brakes. They are nice to use. I think they will be widely used in the future.

How long should I expect before they fail in some way? I am not talking about the brake pads wearing out, but some kind of failure of the brakes.

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This is after I found a way to refurbish brake pads in cable brake calipers.

https://forums.bikeride.com/thread-8174.html

I may experiment with doing something similar with hydraulic brakes in the future.

[jeffg]

From my experience as a shop mechanic if the system is maintained on an annual or semi-annual basis with flush and fills they will go quite a few years without trouble. Cleaning the outside of the calipers after every off-road ride is an important step in regular maintenance. If one runs the brake pads down to the backer or .5mm pad thickness they will have issues with the caliper sooner than those that replace pads after 1-2mm of wear. I must add that Sram and Formula (Italy) are excluded from this as those companies have long term issues. Seal failure the most common. Shimano and Tektro are surprisingly reliable.
As for rebuilding calipers, fahgetaboutit. rebuilds don't last from what I have seen. It has always been customers that do the rebuilds and they just don't get more than a year out of it. All the shops (7) in my area will not do rebuilds because of this, just like auto repair shops do not rebuild brake calipers.
NOTE: Foul conditions create a foul environment for the entire system to operate in and will impact the maintenance schedule.
NOTE: Avoid any Elixir model brakes. Known for reliability issues.

[ReapThaWhirlwind]

Can't say I've ever rode a pair to absolute failure, but I would imagine they should last a good 4 years if well kept.

I've really enjoyed hydraulic disc brakes for the modulation they provide. It's a smoothness you can feel over cable mechanical ones.

[ichitan]

My brakes have 'ASX' written on them. Is anyone familiar with ASX?

Does the brake fluid need to be changed from time to time? It does not in car and truck brakes.

Can I use car or motor bike brake fluid?

My brakes are working well now. I am just trying to learn for the future.

[ReapThaWhirlwind]

ASX Is usually SRAM Red.

Are you sure it doesn't say RSX? That's an off-brand from China.

I don't think you can use car brake fluid as that's for air brake systems with much more pressure. I would stick to the traditional mineral oil fluid specifically for bike hydraulic brakes.

[ichitan]

I made a typing error. It is RSX. It is probably from China. Has anyone had experience with RSX.

[ReapThaWhirlwind]

Don't have any experience personally. I plan on trying out the Zoom mechanical/hydraulic hybrid ones soon though.

[Lss555]

I had hydraulic disc brakes on a trek scratch when I was younger, I bought the bike used and it had been in a flood so I believe I got the brakes redone or new ones after I bought the bike (as I got it for dirt cheap) and rode it 40-50 days a year for 4-5 years, only had to ever replace the break pads. I think they were shimano I want to say. I think as long as you take care them they’ll last a long time.

No experience with RSX though

[Sybian]

(03-06-2023, 03:18 PM)ReapThaWhirlwind Wrote:  ASX Is usually SRAM Red.

Are you sure it doesn't say RSX? That's an off-brand from China.

I don't think you can use car brake fluid as that's for air brake systems with much more pressure. I would stick to the traditional mineral oil fluid specifically for bike hydraulic brakes.

Air brakes do not use hydraulic fluid; they use compressed air; thus the term "air brake". Cars and light trucks use hydraulic brakes, not air brakes. I have worked on them for 50 years. The primary difference in hydraulic brake fluids (mineral oil or DOT) for vehicles is their composition regarding a manufacturer's specifications to avoid breakdown of seals, proper lubrication, boiling point, anti-corrosion, etc.; be it a DOT or mineral oil fluid. I have no idea what DOT type of hydraulic fluid is used in bicycle brake systems, but there is probably a DOT rating spec for it, and it more than likely is the same, or very similar to brake fluid (glycol, or silicone based) used for automotive applications. You should use the same DOT rated fluid as suggested by the manufacturer, but be it bicycle or automotive it should be okay while using the same DOT rating. Since automotive fluid is probably rated for a higher boiling point it is more than likely an acceptable substitute if it will not cause seal deterioration and provides proper lubrication (DOT 3 & 4 are compatible to each other; not DOT 5-Silicone). Many auto companies suggest using their proprietary fluid, but it is more of a marketing scheme and substituting a comparably rated fluid has never created a problem in any automotive application that I have experienced. Mineral oils are probably marketed the same way, and may contain specific additives by each manufactuer related to their specific brake systems (I tend to think that the prime difference will be a color additive). The only way to be sure is trial and error if you want to test different brands (It's your safety at risk). Regardless, fluid should be replaced if at any time it becomes discolored which is a sign of contamination (DOT-moisture); often caused by seal(s) going bad, or other mechanical wear. DO NOT SUBSTITUTE DOT FOR MINERAL OIL OR VICE VERSA IN ANY APPLICATION AND ALWAYS USE THE SPECIFIED RATED FLUID

I am contemplating a front hydraulic disc refit for my new bike; and I will look for a brake system with a DOT fluid compatible to an automotive application to make it easier to obtain and cheaper then having to buy a bike manufacturer's proprietary brand of mineral oil at a bike shop.
Hopefully more input on this thread regarding durability of hydraulic systems.

[ReapThaWhirlwind]

I mean the pressure in the line.

Anyways, I've seen this question asked many times over and vehicle brake fluid is not compatible with bike hydraulic brakes.

Google says the reason for this is due to the base. Be it silicon, glycol, or otherwise.