Can a hydraulic brake line have invisible damage?

A bunch of brakes use DOT 3 or DOT 5.1. It is 95F here today; that is unusual. I see a huge fog bank off the coast that will roll in about three hours from now, by 4:15 PST. A guy, Nathan, had squeaky brakes. He called me to see if I had some brake oil. I said, Yes. When he showed up I figured out he wanted to put it on his rotors to quiet them!
 
Reminds me of funny story... This one time at Band Camp I had a bike with invisible damage and I unknowingly rode it for 15 years without issue.
The only way I found out was one night at 4am when I couldn't sleep I for some reason went to check on the bike... and when I did....
Screenshot_20260714_162153_Gallery.jpg

This guy was on the handlebars with an acetylene torch
 
Well like I said I wouldn't do a full bleed or fluid change... I would just top it off with the lever bleed which only requires removing the lever bleed screw.
He said the problem developed after swapping handlebars a few times. To me this information points to air at the lever.. Which also happens to be one of the most common brake issues.
Then add with all the issues he has with bike repairs and tools he probably only has less than 1000mi on the bike so I would K I S S


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ymmv
True, but he could also cocked the olive. I get KISS, no problem with that. 3 years of age on mineral oil is still three years on oil that retains water. Changing it is not overkill, and it lets you inspect the system, especially when he has different brake problems on each side.

No worries, I won't be working on your bike anytime soon. 😁
 
Do you know of any hydraulic brakes for bicycles or ebikes that Don't use mineral oil?

I've never heard of DOT 3 oil on a bike.
My motorcycle was DOT 3 (or 4?) though.
SRAM and Hayes use DOT.
Tektro says you can use their proprietary oil or generic cycling mineral oil. Gosh, that would include 3-in-1 Oil, invented 132 years ago as a generic cycling mineral oil. It also sounds like my Singer sewing machine oil, bought about 60 years ago, when California Dreamin topped the charts. The bottle says it's for bicycles and computers.

I'll be sure to let you know if they send Singer sewing machine oil with my bleeding kit. :D
 
My brake went all smushy again today.
I do it all the time. 😁
I've had my bike upside-down a few times lately.

I just lean the ebike over to get the reservoir filler screw at the highest point, then I flick the brake lever to pop the bubbles back into the reservoir.

I don't remove the filler screw.
I just work the bubbles to the other side of the plunger, and back into the reservoir.

I don't normally work a bubble all the way to the rear caliper, but if I do, (normal flicking didn't work) I have to stand the bike on the rear wheel and let the bubbles rise up the brake line.

Tipping the reservoir so the filler screw is highest also works the bubble into the chamber of the reservoir that's under the filler screw.
Then you can set the reservoir flat to remove the filler screw to add oil.


Here's another post with me messing with my brakes.


 
The wheelie kids mostly have upside down reservoirs. Suddenly the brakes stop working. A single mom came in with her kid today with no brakes. I fixed it in a half hour with new sintered pads. Flatout is the easiest sell in the world. For the price of one tube in a box, you will never get a flat for the life of the tire. I have them look up an AI review. What will you do at work if he gets a flat 2 miles from home at 3:00? Thorn season is fast approaching with back to school. Soooooooooooooooold. I made good money on that and she is so happy she gave me a five-star review on Maps. Her son will take the CHP certification safety class along with her. Then keep it in a ziplock under the saddle, if he is ever questioned. I showed her how to program the Reave so it is legal and how to tighten the inside adjustment on the mechanical brakes every two weeks. She lives 30 miles, and 20 bike shops away. No one else would touch it. she called them all. It was done in a half-hour. I used the go get a burger and a shake and come back, it will be finished by then line. They return happy and full then tip nicely too. She will also tell the other moms.

 
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Then replace the pads with bronze sintered.
That reminds me... A year ago, I had to replace my front pads. IIRC, they'd worn out in under 2 years because the caliper had come from the factory out of alignment. The OE were resin. I had some on hand but forgot. I ordered semi-metalic to see if I liked them.

The OE in back were fine, so I had resin in back and semi-metallic in front, to compare. The semi-metallic required more pressure. It was worse when I checked by applying one brake at a time. I knew why. Normally, I applied both brakes together, and it was natural to use equal pressure. With a higher coefficient of friction, the back pads were doing most of the work, while front pads were gently polishing away the bedding. A little hard braking with the front alone would improve the bedding and the brake would work better, but that was temporary.

I'll do what I should have done a year ago, put the other semi-metallic pads in the back. With equal pressure, front and back should each do half the work. Then I can decide if I like semi-metallic.
 
The bronze also conducts heat away a little better than organic resin. I suspect that organic pads come with new bikes because they do not require initial bedding. And are at first smoother and quieter. Bronze sintered kick butt but need bedding and are at first louder.
 
I find ceramic pads to be best for my needs. Excellent with regards to wear and heat, quiet and much less rotor wear than anything with metal embedded.
Resin comes stock because they are quiet and cheap... But don't last very long
ymmv
 
I find ceramic pads to be best for my needs. Excellent with regards to wear and heat, quiet and much less rotor wear than anything with metal embedded.
Resin comes stock because they are quiet and cheap... But don't last very long
ymmv
the ones I have tried were horribly noisy in winter. the squeal when they got wet was horrendous. but it could just be that brand.
 
the ones I have tried were horribly noisy in winter. the squeal when they got wet was horrendous. but it could just be that brand.
I'm surprised as ceramic pads are what's used on most cars and recommended by mechanics for everything but high performance.

Ai repeats what I've been told and my experience.
"Ceramic is currently the most popular brake pad material for passenger cars due to its quiet operation, low dust output, and long lifespan. Semi-metallic pads are the top choice for heavy-duty hauling and performance vehicles, while organic pads come standard on roughly two-thirds of new U.S. vehicles."

Ceramic pads—most commonly used for automotive braking—are high-quality friction components made of dense ceramic fibers, bonding materials, and fine copper fibers. They are highly regarded for everyday commuting because they produce minimal noise, generate light-colored, low-corrosive dust, and are gentler on brake rotors.

Pros: Exceptionally quiet, long-lasting, and keep your wheels cleaner than traditional semi-metallic pads.
Cons: Generally more expensive and do not dissipate heat as well, meaning they are not recommended for heavy-duty towing, extreme cold weather, or high-performance track driving.
 
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