Mountain Biking - Hydraulic Brake System Leaking Fluid

Hi All,

I'm new to this forum and I need your guys opinoins on brake system.

I have a mountain bike with full suspension, disc brakes with hydraulic brake system. The bike is about 10 yrs old and I rarely ride it.

The hydrulic fluid leaks, hence cause brake malfunction. I need to bleed the brake line and add fluid every couple weeks. I have been using the oil I bought from Wal-Mart. Someone in the bike shop told me I should have used special bike brake fluid for it, so now the oil caused the brake to leak. Does it make sense to you guys?

Should I replace the hydraulic brake system with classic cable brake system?

I apprciate any inputs.

What kind of fluid did you use in the brakes and what type is supposed to be used? Using the wrong fluid can cause the seals to swell which can lead to leaking.

It sounds like the best option would be to find a suitable replacement. Considering that it doesn't sound like you do a whole lot of mtb'ing, a cable brake system may be suitable(either disc or v-brake).

If you're mechanically inclined at all and like to tinker, I'd think you could find a seal rebuild kit for the brakes and stop the leak. Then just make sure you use the appropriate fluid when you put them back on the bike and they should last a while after that before needing any service again.

But otherwise I think a nice lower budget cable disk brake system would be a good route to go. You should be able to find Avid BB7s online for ~$50 per caliper/rotor. Then you'd need levers, which can be found for cheap. I bet you could have a nice cable pull set-up for ~$150ish.

I have the 6 piston Navigator hydraulic brake system. I used some clear lubricant oil I got from Durane Reade. Do I need to puchase the whole set if I decided to switch to cable brake? Are all hydraulic brake system unreliable and easy to break?

Do I need to puchase the whole set if I decided to switch to cable brake?
Yes...you may be able to use the rotors, but might as well get rotors that match the new brakes


Are all hydraulic brake system unreliable and easy to break?
No way. Your problem was caused by not using the right fluid. MTB disc brakes will either use mineral oil or DOT fluid. Use what the manufacturer recommends and all will be good.

Don't buy bike parts/materials at Walmart.

don't buy things at walmart.

ftfy :)

..... Are all hydraulic brake system unreliable and easy to break?

not at all, but perhaps systems that are 10 years old that probably haven't been serviced and had the wrong fluid put in them are.

you can buy a set of shimano brakes relatively inexpensively and they will be quite reliable.

Thanks for all the inputs. I double check with the oil I used for my brakes. It's Durane Reade Mineral oil. So I can continue use of this oil?
I googled for Navigator MTK hyraulic brake system and nothing popped up. I'm trying to fix the brake leak problem, but first I need to find out where the leak is. Someone mentioned about seals, where are they located?

you can buy a set of shimano brakes relatively inexpensively and they will be quite reliable.

Are you talking about hydraulic disc brakes or cable brakes?

Are you talking about hydraulic disc brakes or cable brakes?

i was talking about hydraulic.

I think it's safe to say that you're not going to be able to find a rebuild kit for your specific brakes. Again, the best option will be to move onto something else(even if you are mechanically minded and like to tinker)...
Find a used set if you can. Also, it's very likely that the brakes you have operate on DOT fluid and not mineral oil - even so, it's a better idea to use the fluid that the manufacturer recommends especially when it comes to mineral oil...DOT fluid can be picked up at your local autoparts store or even wal-mart(just get the right level).

i was talking about hydraulic.

Would you recommend a particular model? I probably can do some research on it in terms of affordability. Thanks