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Discussion Starter · #1 ·
thanks in advance for your inputs fellas,

:madman: so damn again ..this is 2nd same test trail. this is what keeps happening. fire road, light trail(no hard braking) the brake tension is good. Then going downhill, I'm grabbing my brake lever tighter of course going dh….then all sudden no tension and brakes won't engage…relying only on front brakes. happen at same spot, same trail last week. I dismount, check the cable bolt and isn't loose. I pull the lever and see the part holding the cable is moving(don't know what this particular part is called, i can post pic if you need) . so then i loosen the cable bolt, pull cable taught, move that bolt lever up to increase tension-then this is moving the outside brake pad closer to the rotor.
I have basic tekro mech disc brake 09' age.

So why am i loosing the tension/brakes not engaging only downhilling? I just installed new housing and cable. Basic jagwire and ss cable. the first time this happened, i cut both ends of the housing to make sure they aren't fringing.

SO what's the prob, what causing this? this is my first build and don't want to bring to LBS if i can fix myself...:confused:

thanks fellas for your time.
 

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First, are you sure you installed brake cables and not shifter cables? Sounds like they are either stretching or slipping loose a little bit. Not familiar with that particular brake so I can't be of any specific help. I'm sure that somebody more familiar with your brakes will chime in.
 

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Discussion Starter · #3 ·
no prob ...and yes i used the correct cable.
 

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RAKC
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Here's a question, does the extra cable that sticks out past the mount on the caliper get shorter and slack in the rest of the cable each time?

If that's does apply which figure it would, its possible because ur riding the rear brakes so hard going down that they heat up, metal expands when hot and cable slips. Partially sounds as if your relying to heavily on the rear brakes instead of both front and rear. Your expecting more than the rear brake has to give. Other thing that comes to mind is there should be a bolt with washer, is that washer still there?

First use front more. And if your pulling that hard to get any stopping power out of the rear, check your pads, clean your rotors properly etc. Then re-bed the brakes properly. Tecktro mechanical brakes suck but not that badly.

Second is turn all barrel adjusters for the cable in so cable is at max length. Set caliper arm so outer pad is fairly close to the rotor (2-3mm) and while holding arm there tighten the bolt that holds the cable. Once that's done just hold the arm with one hand and give the bolt a good tighten, and an actual solid good tightening. Just because its kinda tight doesn't mean its tight enough. If its not flattening the cable out its far from tight enough. Then bend the extra cable over the bolt/arm so it has a good solid bend right where it comes back out from under the bolt.

That's what im coming up with. Never had this kind of issue with any mech brakes but I tighten the hell outta brake cables.

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Discussion Starter · #5 ·
Here's a question, does the extra cable that sticks out past the mount on the caliper get shorter and slack in the rest of the cable each time?

If that's does apply which figure it would, its possible because ur riding the rear brakes so hard going down that they heat up, metal expands when hot and cable slips. Partially sounds as if your relying to heavily on the rear brakes instead of both front and rear. Your expecting more than the rear brake has to give. Other thing that comes to mind is there should be a bolt with washer, is that washer still there?

First use front more. And if your pulling that hard to get any stopping power out of the rear, check your pads, clean your rotors properly etc. Then re-bed the brakes properly. Tecktro mechanical brakes suck but not that badly.

Second is turn all barrel adjusters for the cable in so cable is at max length. Set caliper arm so outer pad is fairly close to the rotor (2-3mm) and while holding arm there tighten the bolt that holds the cable. Once that's done just hold the arm with one hand and give the bolt a good tighten, and an actual solid good tightening. Just because its kinda tight doesn't mean its tight enough. If its not flattening the cable out its far from tight enough. Then bend the extra cable over the bolt/arm so it has a good solid bend right where it comes back out from under the bolt.

That's what im coming up with. Never had this kind of issue with any mech brakes but I tighten the hell outta brake cables.

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cable slack is not getting shorter. I move the cable bolt as i assumed it wasn't tight enough, but i have and did tighten it down and the cable showed that it gotten flatten.
i do rely heavy on the rear brakes going down. washer on cable bolt is there. i will remove the cable readjust the barrel and see what happens tomorrow. thanks
 

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When you lose all power and check the caliper, is the piston moving to contact and squeeze the rotor? If not, something got loose and keeps getting loose since its happening multiple times. I would buy a new cable and start again. Continuing to tighten on an already flat cable isn't going to hold strong. If you have lever tension, but, just get no friction response when the pads squeeze the rotor then you may be heating up the pads and gassing them out. This will almost create an air pillow between the pad and rotor that only allows very little friction.

At least its not your fronts :eekster: .
 

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cable slack is not getting shorter. I move the cable bolt as i assumed it wasn't tight enough, but i have and did tighten it down and the cable showed that it gotten flatten.
i do rely heavy on the rear brakes going down. washer on cable bolt is there. i will remove the cable readjust the barrel and see what happens tomorrow. thanks
You shouldn't be relying so heavily on your rear brake going downhill. Try to even up the pressure between the front and rear. We all have a tendency to drag our rear brake on extended downhill runs. You are not going to GOB using your front brake a bit more, don't worry. Your stopping power will be considerably better too with more even use between both brakes.
 

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Discussion Starter · #8 ·
When you lose all power and check the caliper, is the piston moving to contact and squeeze the rotor? If not, something got loose and keeps getting loose since its happening multiple times. I would buy a new cable and start again. Continuing to tighten on an already flat cable isn't going to hold strong. If you have lever tension, but, just get no friction response when the pads squeeze the rotor then you may be heating up the pads and gassing them out. This will almost create an air pillow between the pad and rotor that only allows very little friction.

At least its not your fronts :eekster: .
hay jetboy dude is that your hooligan tattoo? if so, dammmm that is awesome !!!!:cornut::cornet: i used to have a few buddies, we called our selves the hooligans and having hooligan night where we'll surf all morning grab our old school beach cruiser and booze it up all over Venice, CA….that just brought flashbacks, lol sadly they moved to Nicaragua.

Ok back to no brakes. the piston is moving as i squeeze the lever, but no friction/contact point on the rotors. would a basic/cheap galvanized cable be one of the causes since i assume they are practically about $1. In regards to lever tension, It's squeezed all the way to the grips-so i assumed theres no tension. So when you say heating and gassing, what does this mean? Sorry noob here on brake system.

hawg-You shouldn't be relying so heavily on your rear brake going downhill. Try to even up the pressure between the front and rear. We all have a tendency to drag our rear brake on extended downhill runs. You are not going to GOB using your front brake a bit more, don't worry. Your stopping power will be considerably better too with more even use between both brakes.
your dead on, I barely use my fronts, as I'm thinking holy crap OTB. this i assume falls under technique correct? It might be coming from this being my first build and this being my 2nd test run.

So what do you fellas recommend, should i get new brake cable reroute and check barrel adjuster? should the barrel be threaded all the way in when the cable in being installed? Does this have anything to do with the housing?

:thumbsup: Dude i appreciate this soooooo much. thank you guys.
 

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Discussion Starter · #9 ·
one other thing happened. as i loosen the cable bolt to move the piston higher to compensate for the lack of tension, it then moves the pads towards the rotor basically touching them. So i'll have to lower the piston and pull the cable as taught as possible.
Should i take apart the brakes? don't where to start thanks.
 

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RAKC
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Ok first off if you brake lever is anywhere near the grips they are set up horribly wrong, way too loose. Inside pad should be no more than 1-2mm away from the rotor, closer to the 1. Best way to set is slowly bring inboard pad closer till it starts to rub then back off just slightly so u can see a small sliver of light between it and the rotor. Same way for the outer pad but you can have a tad more gap if you want. Put it this way any brakes I've had of any type i can never get the lever even close to the grips unless I pull hard enough to break them. Set the cable as I explained before doing this though.

Also dont take brakes apart, check that the bolt that attaches the arm to the caliper is tight. Not the one for the cable but there should be a hex bolt head at the base of that arm attaching it to the caliper.

After all that's done clean and bed brakes (your on ur second ride when this is happening, part of your problem is breaks aren't bedded yet, so they hardly working). Ur actually going to mess up ur brands you keep running a long downhill before they are set up properly. At this point you may have to take sandpaper to pads and rotor to remove glaze then set everything back up again. Been there done that lol, happens to all of us first time around.

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Discussion Starter · #11 ·
Ok first off if you brake lever is anywhere near the grips they are set up horribly wrong, way too loose. Inside pad should be no more than 1-2mm away from the rotor, closer to the 1. Best way to set is slowly bring inboard pad closer till it starts to rub then back off just slightly so u can see a small sliver of light between it and the rotor. Same way for the outer pad but you can have a tad more gap if you want. Put it this way any brakes I've had of any type i can never get the lever even close to the grips unless I pull hard enough to break them. Set the cable as I explained before doing this though.

Also dont take brakes apart, check that the bolt that attaches the arm to the caliper is tight. Not the one for the cable but there should be a hex bolt head at the base of that arm attaching it to the caliper.

After all that's done clean and bed brakes (your on ur second ride when this is happening, part of your problem is breaks aren't bedded yet, so they hardly working). Ur actually going to mess up ur brands you keep running a long downhill before they are set up properly. At this point you may have to take sandpaper to pads and rotor to remove glaze then set everything back up again. Been there done that lol, happens to all of us first time around.

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thanks Tig, the brake system was swapped over from my other bike. I've gone dh on that prior bike many times and never gave out on me like this. My brake lever where set up (i assumed) correctly maybe like a touch under an inch when brakes engaged locked. Only reached the grips when the brakes failed these two times. There is 1mm glimpse of light between both pads and rotors. I've checked the bolt that moves the pads horizontally(towards or away from the rotors) and is good space.

what do you mean by bedded? if these brakes are working fine elsewhere(not dh) is the brake tension not setup properly or is there a certain amount of pressure/tension when pulling the lever causing something to "pop"….Should I replace/get new pads & cable ?

I appreciate this SOOO much thanks.
 

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RAKC
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Ok I misunderstood the lever issue. I'm assuming each time that this happens the outer pad comes all the way back, cable slips and arm is all the way in start position again.



For bedding google search it, it wiil explain. First thing rubbing alcohol the rotor then dont touch it with fingers or any oily fluids.



Go ahead get new cable, no need for fancy just go to lbs get what u need and make sure its brake cable. If u can find new pads that's good too being what u put these through already.



Setup brakes with new parts being careful not to touch braking surface of pads or rotor with fingers or anything with oil or grease on it.



Go through bedding procedure, stay off that dh for a few rides.



Ull know ur brakes r ready when u hit fronts hard and bike dives hard, similar feeling rear. Ull know cause braking power rapidly starts increasing with less force pulling on the levers.


Finally use ur front brakes!!! Lol

And save up for better brakes!


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Discussion Starter · #13 ·
For bedding google search it, it wiil explain. First thing rubbing alcohol the rotor then dont touch it with fingers or any oily fluids.



Go ahead get new cable, no need for fancy just go to lbs get what u need and make sure its brake cable. If u can find new pads that's good too being what u put these through already.



Setup brakes with new parts being careful not to touch braking surface of pads or rotor with fingers or anything with oil or grease on it.



Go through bedding procedure, stay off that dh for a few rides.



Ull know ur brakes r ready when u hit fronts hard and bike dives hard, similar feeling rear. Ull know cause braking power rapidly starts increasing with less force pulling on the levers.


Finally use ur front brakes!!! Lol

And save up for better brakes!


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Thanks Tig. I Really appreciate the help. The cables are new. This would be the 2nd ride on these new cables.
So I took the pads to lbs they said they were still good, about 1.5 mm thick excluding the backing plate.( usually they But what they noticed was that they were glazed smooth out. Said to sand it down. Just sanded now and looks/feel better.
Just googled bedding process (thanks for that tip btw) , my rotors r also glazed( striated lines) so gonna work on the rotors too.
.
Does it matter which model Tektro. I have the IOX.. Well you and the lbs recommended to upgrade lol...

Thanks for the help
 

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RAKC
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No when it comes to bedding the process is the same for the cheapest or the most expensive, doesn't matter.

Since all is well mechanically go through set up, bedding and stop cranking the brakes that hard lol, you should be fine till you upgrade.

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