Around

I picked up a pair of ZTTO mechanical (cable operated) hydraulic disc brakes for a new build virgin frame. After installing the brakes, they aligned easily and provide plenty of braking power. However, after braking, the calipers are very slow (weak) to re-open. I have tried removing the cable to eliminate the resistance but the calipers are both still very slow to re-open and return to a normal open position. I don't see an adjustment to tension the return spring. Wondering if there is a hidden adjustment, if adding fluid would help, or if there is some other solution?

I would take it to the local bike shop for professional advice or repair but the bike shops in my area are incapable of working on bikes.

gesta

Here’s a photo of how I solved similar problem. It’s not the same brand of brake caliper as you have, but these generic cable actuated hydraulic brakes tend to be quite similar.

My rear brake was bit sluggish to return so I simply added extra return spring between cable stop and lever arm.

Around

Thanks, I had considered the same thing. Even shopping for the right size spring but I was hoping for a more elegant fix. I guess this means there is no adjustment to fix this issue and adding oil probably isn't necessary?

andrewclaus

How are your cabling skills? Are there any bends or extra length in housings? Are housing ends prepped well? Do both brakes behave the same? If the rear is worse, suspect cabling. Sheldon Brown has a good article on that.

The hydraulic calipers I'm familiar with, which isn't an exhaustive list, rely on the shape of the rubber piston gaskets to back pistons off. Automobile brakes don't bother with that, since you never notice the slight drag. Adding the spring to counter cable friction is a pretty good idea.

As long as the hydraulic action is firm, adding more brake fluid won't do anything.

Around

Thanks, the rear is somewhat worse than the front but both are quite slow to return even with the cables removed.

So, apparently there is no adjustment and as you say, more oil isn't going to help. I guess I will have to resort to a spring.

Surely, this must be a common problem? I guess I will just have to chalk it up to typical Chinese engineering and be thankful the brakes work at all.

Koyote

Seems a weird comment, given that you are apparently also incapable of solving this problem.

Around

Maybe so but am not a bike mechanic and don't claim to be one.

There are three bike shops in my local city. One of them purely sells bikes and offers no service. The second one is a Trek dealership and will only work on Trek bicycles. The third one, who sold me an inexpensive Chinese MTB about four months ago claims to be a general bicycle service facility. I took this same bicycle back to them to have the hydraulic brakes bled for me. I was annoyed that they charged me for the service due to the fact that I bought the bike from them and it was only four months old. I didn't express my disappointment and simply paid the bill without further ado. When I got home and rode the bike, the brakes were even softer than prior to the repair. They had almost no stopping power and squealed like a newborn. Obviously they had spilled oil all over the disc and pads without even bleeding the brakes properly. How am I to conclude anything other than the local bike shops are incapable of working on bikes?

In retrospect, maybe you're right, two of the shops are unwilling and one is incompetent. Now I am trying to become my own bike mechanic which explains why I have come here for advice.

Koyote

I think the key may be that you describe the bike as "inexpensive." That would explain why you had low stopping power, and it would also explain why the shop charged you four months later to do the bleed: the brakes had been bled properly and were working as designed. They're just not very good brakes.

I'm not sure, since I've not seen your bike. Just throwing it out there as a possibility. You might be trying to turn a sow's ear into a silk purse.

Iride01 

They might be incompetent, or maybe they just made a mistake. If one mistake makes them incompetent, then that will be every person and shop out there as all have made mistakes.

The biggest mistake IMO, is you not taking the bike back to them and telling them that they didn't fix the issue and that it is now worse.

However if you want to do this yourself, then check to see that the cable has no binding that is not letting it fully release the brake. You can hold the part where the cable attaches and maybe get an idea of this while squeezing and releasing the brake lever with the other hand. You might have to undo the cable from the pinch bolt to determine this.

What might be likely is that there was air in the brake hydraulics from the start and now there is even more. So proper bleeding might help. So find the manual for your particular brake model and read how to properly do that. Then find some youtube videos to watch and make sure they are doing it as your brake mfr says to do it. Otherwise, you won't know if they know another way to do it or they are just some ****er making vids to get their subscriber count up.

Around

Maybe so, as I said, I am not a bike mechanic. However, in my assessment, the brakes were working well for the first four months but were gradually becoming softer while still offering good stopping power. Some oil was weeping from the brake lever and in my untrained assessment, they required bleeding. If in fact they did not require bleeding, but the bike shop decided to bleed them anyway and ultimately worsen the circumstances, this somehow excuses the bike shop? I guess I don't follow your logic. If the brakes are in fact "not very good brakes" and bleeding was pointless, a trustworthy bike shop might have mentioned this fact. Given the evidence, I don't buy it myself.

I am not looking for a silk purse but merely brakes that work as designed.

I will now disassemble the contaminated parts, clean everything properly, purchase the proper tools for bleeding the brakes myself, and see if your premise is accurate. regardless, I will not be conducting business with this said bike shop in the future.

sloppy12

So not to derail but seems like you more than covered a solid solution for the brake issue.

any more info on this bike? looks pretty sweet.

gesta

Thanks! After installing expensive Yokozuna Reaction cable outers and realizing cheap brakes were still going to be cheap brakes, spring was the obvious solution.

That bike started as ~1975 Peugeot Px-50L, I’ve shortened and widened the rear triangle while adding disk tabs front & back. There’s some threads about this bike in Twitter: and , for example.

Around

A mistake? I am not expecting perfection, just basic competency. This was an abomination. The brakes are significantly more squishy or soft then when I brought it in. They apparently didn’t check their work or test the brakes because if they did, their standards are too low to be of any use to me. And they “mistakenly” drenched the disc and pads in oil causing an even worse condition. I have made plenty of mistakes in my time but for a self a proclaimed bike mechanic to get it this wrong, I believe I am justified in concluding that they are incompetent.

Aside from what has turned out to be stellar advice from Gesta, what I am getting from this thread is that I shouldn’t expect a professional bike mechanic to solve a common bike problem unless I have already solved it myself. I should assume that inexpensive brakes get squishy without requiring to be bled. That I am expecting too much and that it’s just an understandable mistake for a professional bike mechanic to not check or test his repair.

Out of curiosity, if I had brought the bike in for a flat tire and they patched the wrong tire, would that be a mistake or utter incompetence? Just trying to calibrate my expectations.

You are correct, I have an obligation to return the bike and explain the issues. I won’t be doing that and here’s why; the bike shop is an hour drive one way. Considering this is taking place in SE Asia where saving face is all important, I have a strong suspicion that they won’t take the critique of their workmanship maturely. But at the end of the day, I am convinced it would be a further waste of my time as I am confident they are incapable of working on the bike to my relatively low standards. I have little doubt I will fare much better by doing the work myself. At the very least, I won’t have anyone to blame but myself if it goes wrong and I will have acquired the knowledge and proper tools for next time.

I think some confusion may have been introduced due to two different bikes in this thread. I was initially asking if there is an adjustment for a mechanical cable actuated hydraulic brake that was slow to return even with the cables removed on a gravel bike. It now appears adding a compression spring is the only known repair solution.

The mountain bike that required bleeding has a fully hydraulic brake system and is a separate issue. I am not looking for advice on that bike.

Regardless, thank you for your advice.

Iride01 

You are most welcome!

Like I said, it's either some binding in the cable housing preventing the lever on the brakes from retracting and allowing the cylinders to be pulled back from the rotor. Or there is likely air in the fluid reservoir which can be bad for putting pressure on the pads as well as bad for pulling the pads away from the rotors.

Both should be easy to check for. If you are going to DIY it, then find some videos and hopefully the manufacturers instructions for servicing them. Park Tool makes some good help videos, but I don't know if they have one applicable to your type of cable/hydraulic brakes.

If the shop is as bad as you seem to indicate from other experiences then you should be looking for another that handles your bike brand for times you might need potential warranty work.

You shouldn't accept squishy hydraulic brakes as normal. But describing what is squishy and what is just normal cable pull being taken up isn't easy to do in simple written text.

Adding a spring will only be a good solution if your cable is binding and you can't or will not resolve the reason it's binding. If you have air in the hydraulics, then it's not likely to help much.

veganbikes

I find it quite unbelievable that a bike shop will only work on one brand of bike, I have not really seen that certainly some shops will not work on certain types or brands of bikes due to unreliability or difficulty in getting parts or just knowing quality is nill but outright only working on one brand of bikes doesn't sound right.

In terms of low end bikes, they come with low end parts that don't work well and no matter what you do they will not really perform that well, you can replace them but in the end if you are going for off-brand and knock-off stuff to replace you are not going to get better performance and maybe sometimes worse but usually about the same. Even the Acera level hydraulic brakes from Shimano are decent enough for the price, not great brakes but generally reliable enough and better than whatever zit or logan or zoom or whatever other odd brands exist out there.

I wouldn't expect a cheap bike from anywhere to be all that great and especially at that price point I know they aren't great. Trying to shove a bunch of stuff on a bike without increasing cost will always decrease quality at those lower price points the goal should be more single speed stuff and less moving parts. If you are going to try and add gears you have to keep it more minimal, stick with a 1x set up stick with reliable parts and again no extra moving parts. If you want to make it more usable give it wide tires not cheap suspension and that will help. Yeah not everyone loves a rigid bike but I would rather have a full rigid bike with slightly better components than a hardtail or worse full suspension with absolute cheap and garbage components.

Around

I can't post a photo until I have made 10 posts so here is number 7

Around

I can't post a photo until I have made 10 posts so here is number 8

Around

I can't post a photo until I have made 10 posts so here is number 9

Around

I can't post a photo until I have made 10 posts so here is number 10

Around

This spring made a significant improvement but I don't like the way it sits. I am trying to source a slightly larger coil diameter spring. I think a 1mm wire diameter x 10mm OD coil diameter x 20mm open length, Stainless Steel compression spring will work better. Thanks for your suggestion.

ClydeClydeson

That kink in the cable right before the caliper is not good. I can't say with any specificity, but judging by this arrangement, I'd be very surprised to find multiple bike shops in an area that have less skill than you. As for the Trek shop, it's likely they don't refuse to work on any but trek bikes, but that they told you that because they don't want to work with YOU.

bboy314

Definitely looks like the housing bend before the caliper, plus step down ferrule seated crookedly in the barrel adjuster is your problem.

Also the quality of the caliper can’t help, just sayin…

Around

Despite the fact that I mentioned more than once that the brakes are very slow to re-open "EVEN WITH THE CABLES REMOVED" you still don't get it. Never the less, you're entitled to your opinion, worthless as it is.

Around

Thanks for your feedback. The cable moves quite freely despite it's appearance. The diameter of the cable end is considerably smaller than the receiving end of the barrel adjust. It sits at this angle with nothing to keep it true.

I don't understand your comment, "the quality of the caliper can’t help"?

Around

Ah, I understand now. Yes, I am sure you are correct. I cheap caliper is a cheap caliper. I don't think that prevents me from trying to find a solution aside from purchasing a high end caliper. I think this is how some bikes get to unjustifiable prices. I don't expect cheap components to preform to the same level as a high end component but I do expect them to function. Maybe I am out of line?