Hydraulic brake caliper fails after 3000 km

[ichitan]

I bought a new bike with RSX hydraulic brakes. After 3000 km, one of the calipers leaks brake fluid.

I am not saying RSX brakes are bad. One failure is not enough evidence. It would be interesting to hear the experiences of others.

It may just be a faulty caliper.

It may be because I am larger than many cyclists, and to stop I need to apply the brakes harder. Applying the brakes harder, may result in quicker failure.

It may be that many casual cyclists may take 5 years to ride 3000 km, which seems like a long time.

So now I am running one hydraulic brake, and one cable brake. The cable brake actually uses self refurbished brake pads.

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

When the other hydraulic brake fails, I plan to go to all cable brakes. 3000 km is just not enough for a brake caliper.

[Sybian]

It would help to specify where the leak is coming from (lever/reservoir, line/connections, caliper, etc.).
Your weight might cause quicker pad wear, but it should not cause leakage. More braking cycles would cause earlier seal wear at the master cylinder or caliper piston even with someone of light weight, but who is always braking constantly for whatever reason. If the pad got worn and was not replaced early enough it could cause premature wear to the piston/seal, if exposed too far out when breaking, allowing fine debris to infiltrate the caliper cylinder and affect operation/durability.

[meamoantonio]

(09-07-2023, 07:52 AM)ichitan Wrote:  I bought a new bike with RSX hydraulic brakes. After 3000 km, one of the calipers leaks brake fluid.

I am not saying RSX brakes are bad. One failure is not enough evidence. It would be interesting to hear the experiences of others.

It may just be a faulty caliper.

It may be because I am larger than many cyclists, and to stop I need to apply the brakes harder. Applying the brakes harder, may result in quicker failure.

It may be that many casual cyclists may take 5 years to ride 3000 km, which seems like a long time.

So now I am running one hydraulic brake, and one cable brake. The cable brake actually uses self refurbished brake pads.

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

When the other hydraulic brake fails, I plan to go to all cable brakes. 3000 km is just not enough for a brake caliper.

I wouldn't trust RSX either, I think its made for that market specifically, the ones that take 3 to 5 years before getting 3000kms of mileage on their ride, Shimano and Sram hydraulic brakes last way longer, I clock in 5000kms in a year and these shimano calipers have been with me since 2020. The most ive gone without bleeding them is about 2 years since I was lazy but they still work. Regular maintenance should be a brake bleed every year

[ichitan]

(09-09-2023, 04:09 AM)meamoantonio Wrote:  Regular maintenance should be a brake bleed every year

Why?

I have had some experience with car and truck brakes. The only time you bleed them is when they get air in the lines. If they don't get air in the lines, you never bleed them. Why should you bleed bicycle brakes, other than when they have air in the lines?

[enkei]

(09-09-2023, 08:44 AM)ichitan Wrote:  

(09-09-2023, 04:09 AM)meamoantonio Wrote:  Regular maintenance should be a brake bleed every year

Why?

I have had some experience with car and truck brakes. The only time you bleed them is when they get air in the lines. If they don't get air in the lines, you never bleed them. Why should you bleed bicycle brakes, other than when they have air in the lines?

I suspect that meamoantonio is using the term "brake bleed" to mean making sure you only have fresh, clean fluid in the system? But yeah, I agree, unless your braking performance has dropped off, I don't see why you would need to do this every year. I have no experience with DOT brake fluid on bikes, so maybe they need annual attention?

Decades ago, we expected to have to bleed clutches and, sometimes, brakes on cars quite frequently but these days you shouldn't have to do that with cars or bikes.

[Sybian]

(09-09-2023, 12:45 PM)enkei Wrote:  

(09-09-2023, 08:44 AM)ichitan Wrote:  

(09-09-2023, 04:09 AM)meamoantonio Wrote:  Regular maintenance should be a brake bleed every year

Why?

I have had some experience with car and truck brakes. The only time you bleed them is when they get air in the lines. If they don't get air in the lines, you never bleed them. Why should you bleed bicycle brakes, other than when they have air in the lines?

I suspect that meamoantonio is using the term "brake bleed" to mean making sure you only have fresh, clean fluid in the system? But yeah, I agree, unless your braking performance has dropped off, I don't see why you would need to do this every year. I have no experience with DOT brake fluid on bikes, so maybe they need annual attention?

Decades ago, we expected to have to bleed clutches and, sometimes, brakes on cars quite frequently but these days you shouldn't have to do that with cars or bikes.

Bleeding (for removal of both gas and fluid contaminants) should be done regularly based on multiple factors (frequency of use, ambient conditions, temps., etc.). Regardless, if the fluid is at all discolored it should be replaced as soon as possible. If it's really dark then seals are going bad or are already shot. The only real improvements made regarding fluids and brake systems is that seal materials are being designed that are less affected by the fluid breaking them down over time/use, and fluids are designed to have less deleterious affects to seals while improving lubrication and anti-boil properties. This is why you often need to use a specific grade or brand of fluid depending on the specific hydraulic system in question be it a bike brake or other system.

[ReapThaWhirlwind]

Note that Zoom now has hydraulic brake mechanical hybrid calipers.

They are cable pull, while the caliper bay uses a hydraulic piston.

Zoom is a very notable brand that has been leaned on for cheap, effective parts by big bike companies for years.

[enkei]

(09-09-2023, 07:20 PM)Sybian Wrote:  Bleeding (for removal of both gas and fluid contaminants) should be done regularly based on multiple factors (frequency of use, ambient conditions, temps., etc.). Regardless, if the fluid is at all discolored it should be replaced as soon as possible. If it's really dark then seals are going bad or are already shot. The only real improvements made regarding fluids and brake systems is that seal materials are being designed that are less affected by the fluid breaking them down over time/use, and fluids are designed to have less deleterious affects to seals while improving lubrication and anti-boil properties. This is why you often need to use a specific grade or brand of fluid depending on the specific hydraulic system in question be it a bike brake or other system.

Bonus points for the use of "deleterious"!