We have a mountain bike that came equipped with hydraulic disk brakes. They have been trouble since the beginning and as a result she won't even ride it any more.

The brakes bind. It is almost as if you are putting on the brakes but there is no lever action involved.

Last time this happened I made some adjustments and they worked well. A month later, when she got around to riding, they were binding up again.

Is it normal to have to adjust the pads before riding or to do so monthly?

What causes this repetitious binding and how do I remedy it? Is this a moisture/contaminated fluid problem?

Are cable-actuated disks better in this regard? It is only occasionally ridden on streets (no off road riding).

My cars and motorcycles have hydraulic brakes but have never had this problem.

Bike is an otherwise nice TREK, brakes are Promax.

Hydraulic brakes enjoy a well earned reputation for reliability.

The first, and often last place to check is for air in the lines. An air bubble in the line acts like a spring, and can the brakes to fail to retract properly.

Read about bleeding, and either buy the necessary, of have a shop do it

So, I spent some time reading and watching YouTube videos. Let's see if I got this right.

This is likely a air intrusion or moisture intrusion problem and new fluid and bleeding brakes will likely fix it.

This needs to be done annually.

Brake bleeding kits cost approximately $80 to $100, if I can find one for these older model brakes.

I can switch to cable-actuated brakes for about the same price. After all the years of disappointing trouble with these hydraulics, switching seems like a "no brainer".

Am I missing something here?

Your bike, your money, your call.

Learning how to maintain and adjust hydro brakes is a useful skill.
However, they will never be as easy to deal with as rim brakes.

If you’ve already decided to replace the brakes due to the cost of a bleed kit, I see no further troubleshooting required.

If you change your mind, let us know.

BTW, in a Shimano caliper, it’s not the fluid that retracts the pad after braking, it’s the piston seal.
A bubble won’t stop it retracting, but it will soften the braking.
not sure about Promax.

oh, and a Promax bleed kit is $26 including the fluid!

Barry

The way I see it, if it isn't broken don't fix it. As a recreational cyclist I've been using rim brakes for 50 years and they have never failed me yet, not even in the rain. Why would I want to add the complexity of hydraulic brakes. If you think servicing hydraulic brakes is inconvenient, try putting the back wheel on your bike after a flat. I have problems enough just getting the chain and derailleur out of the way, Never mind lining up the disc with the caliper.

i won't buy a bike with disc brakes. When the time comes to replace mine, the brand that still offers a nice bike with rim brakes will get my business.

Perhaps, for serious racing where absolute control is important, or perhaps hard core mountain biking there might be justification for them. But for the average cyclist not so much. It certainly adds to the bottom line of many bike shops as many folks will not service hydraulic brakes them selves. That's one reason they are promoted so aggressively.

I ride an ebike in the off season and it has hydraulic disks, they are fantastic, and although I love my lightweight bikes, the brakes on the ebike are confidence inspiring.

yes they are a little more challenging to maintain. If you are not able to do that maintenance or pay to have it done, then you probably should not ride a bike so equipped as the brakes are a primary safety system.

/markp

I've had my bike with hydraulic brakes since March of 2020. The only thing I've done is pull the pads every great once in a while to check their thickness.

If your bike was a new bike and doing this regularly then why haven't you gone to see your Trek dealer?

Not rim brakes, cable actuated disk. A lot easier to adjust if you have a problem out riding. But I'll take a quality set of hydraulic brakes anyday.

a bleed kit I maybe 20 or so a full kit to do al brands is about 120.00 just take it to a shop and have them deal with it so you can ride the bike.

Yes, absolutely

I use cable disk brakes for on road and heavy off road uses and they are worth every penny.
No maintenance, no mess, no fluids.

Unless you're downhill, e-bike, or making a statement, hydraulics are a waste of time.

Thank you, the cheapest I found was at least 3X that price.

My levers are marked "DOT 4" not mineral oil but that is a minor issue.

+1 After this experience, I would never again buy them for a bicycle. I am feeling really sour about them right now.

They were sold to us as a great thing. They have proved to be anything but. They have caused the bike to go unridden almost since we bought it.

It really is neither of those issues, markp. Still, you are 100% correct.

It is not knowing such annual maintenance was mandatory. It is not having the bleed kit and fluid them on hand.

It is not so much the money as it is having to drive the bike to the shop drop it off, having to wait for them to do the work, then driving back to the shop to pick it up - each a two way trip.

Heck, we just wanted to go for a ride today. The thing is, the brakes are locked up and the wheels won't roll.

The original shop, BIKECOLOGY, has long since closed.

I never had trouble on my motorcycles or cars. I guess I made a mistake buying this particular bike and have lost faith in hydraulics for my particular application.

Who makes a decent set of cable-actuated disk brakes?

I don't want to spend the money for PAUL Klampers ($300/caliper plus levers and cables is too much).

Or you should have just taken it to a shop to get it fixed. way more time was spent complaining about it then it would have taken to ether learn how to fix it or take it to a shop and have them fixed. How long has the been going on without getting the problem fixed?

Thanks for all the help, sanity-checking and guidance.

It is a major issue.

Never mix them.

DOT fluid is corrosive, so you have to take extra care.

Also, it suggests the brakes are Avid/SRAM. Their economy versions are a nightmare and behave as you describe.

I would take this to a shop and have them fix it. If they can't do that readily, cut your losses and install Shimano.

Don't go for cable-actuated disc brakes. It is a step backward. Go for properly functioning hydraulics.

DOT kits are more expensive. I’m not sure if it’s the cost of the fluid, or if the equipment is from DOT proof materials.

Just be aware you absolutely must not use the wrong fluid for your brake type.

Barry

BTW I don’t bleed them annually.
Mine hasn’t been done in over 3 years (6000 miles)

Barry

Get some Avid BB5(MTB) with matching Avid Levers, or BB7(Roadbike) Cable Actuated Disc brakes, and thank me later.

If the cable housing setup is a thing you're not already familiar with, take the bike to a shop... ask for stranded brake cable housing.

DOT 3 or 4 brake Fluid eats almost ALL plastics, paints, etc...it slowly removes the Paint right down to bare metal, then Can't be painted over without a lengthy cleaning of the area, including back a ways from the obvious bare metal... ONE DRIP can cause a bare spot.

the material is the extra cost.

AND, as a Warning to anyone else reading this.. DOT 5 IS NOT a "better grade".. It DOES NOT mix well with other DOT fluid and WILL RUIN the seals and many other parts in a Brake System designed for DOT 3 or 4.... And Vice-Versa is also true.

It doesn't have to be the place you bought it from. Any Trek dealer will do, or a authorized repair place. Which might be most any bike shop. You'd take your new car or motorcycle back to a authorized dealer if it had issues from the start, wouldn't you?

I have several TRP Spyke calipers, they're pretty good. Otherwise the Avid BB7 is quite highly regarded. Cable discs generally have the disadvantage that they require fairly frequent adjustment to compensate for wear, while hydraulic systems are mostly self adjusting.

Making a statement? Huh?

Sorry but good quality hydraulics take very little time and very little maintenance. Replacing pads and rotors is the same for both and in the end a brake bleed every few years vs replacing cables and housing what should be yearly is not bad and in the end I can just go to a shop and have them do it if I don't want to do it. I have ridden my Magura brakes for over 4k miles and aside from some pads which again you would do on any brakes and replacing a front rotor because I wanted a larger rotor they have had zero problems. People who have issues with brakes probably just aren't doing things correctly and that isn't always a bad thing it is just some people are good at some things and some people are good at other things.

Oh and just FYI all things on a bike for the most part need maintenance if you aren't doing maintenance then you could be doing damage. Take care of your bikes people!