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jj65

Front Braktec Problem

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I noticed on Saturday, after riding through deep dirty water in a section, that the front brake became almost useless and the lever was very spongy, until I pumped it a few times and used it a couple of times to clear the water from the pads. I have never noticed this on my previous bikes with Ajp brakes.

Has anyone else noticed this? With Braktec setup (another mont 260 rider with the standard bike also commented on this).

Edited by jj65

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I ran the pads in on my bike with water. I spray the disc and caliper with a spray bottle and do some rides up and down the driveway. Water took some time to evaporate and give good brake on each application of the water.

Did it ten times for front and back brakes. Back took much longer to dry water as rotor is not slotted. After done I spayed both brakes with brakekleen and compressed air. Made sure discs were getting hot (water gone, ride til coolish, go again).

Could be a function of the standard pad composition????

All brakes don't work that well when cold disc and wet.... but you said the AJP did! Mmmmmm.... still might come back to pad composition? Usually the pad wear slots shed water pretty well but if a dead cold disc from being immersed????

Pads from new need to reach a certain temperature to "set" them. Best done as a gradual rise in the temperature then cool and on to next temp rise. Some of the new car pads come with temp indicator dyes. You heat pads until first dye disappears and let cool, then up to next dye marker disappears et cetera.

I'm not saying do this for trials bike , just illustrate once pads are "set" they may deal with water better????

Mags

Edited by mags

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Is there much life left in the pads ? No problems myself but others with older bikes have reported the brake being spongy when pads are low.

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Plenty left on them. They are not spongy normally, only that time when they got very wet.

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The piston seals and other brake components are designed to retract the piston a set distance when the pressure is released. AJP and Nissin calipers tend to have very little piston retraction and the pad stays close to the disc clearing water and mud continuously. Other brakes have more retraction and are more prone to not scraping the water and dirt from the disc, and having the pads pushed back by water or debris on the disc. It may be that Braktec are designed to have quite a lot of retraction.

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The piston seals and other brake components are designed to retract the piston a set distance when the pressure is released. AJP and Nissin calipers tend to have very little piston retraction and the pad stays close to the disc clearing water and mud continuously. Other brakes have more retraction and are more prone to not scraping the water and dirt from the disc, and having the pads pushed back by water or debris on the disc. It may be that Braktec are designed to have quite a lot of retraction.

I didn't know that, I thought all brakes worked the same way. Surely Braktec would design a trials brake system to keep the pads close to the disc all the time.

I am surprised no one else who has a new bike with Braktec's hasn't commented, as there must be quite a few bikes with these now. All I wanted to know is, is it a fault or normal ?

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I didn't know that, I thought all brakes worked the same way. Surely Braktec would design a trials brake system to keep the pads close to the disc all the time.

I am surprised no one else who has a new bike with Braktec's hasn't commented, as there must be quite a few bikes with these now. All I wanted to know is, is it a fault or normal ?

Just because its on a trials bike it doesn't guarantee it was designed for a trials bike.

Most newer bikes don't seem to be designed for our wet muddy ground. (south east England)

TLTEL

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It does seem strange because as far as I know AJP and Braktec are the same, but some seem to think their 2014 and possibly 2013 callipers are not the same as earlier versions although I can't confirm that.

PS what not to do with a sticking brake - Don't spray it with WD40 and force the pistons back. The WD40 will soften and swell the seal rubber then forcing the pistons back will rip the sealing edges off the seals.

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I just thought I would post a bit more on this, even though it may not be completely relevant to the original post.

http://am.delphi.com/pdf/techpapers/2002-01-0927.pdf

See the above.

Seal performance / retraction is significantly influenced by brake fluid lubricity, perhaps changing your fluid will alleviate the 4t brake problems.

Had a bit of a job recently sorting a front AJP 4 piston caliper. Pistons were not retracting properly due to corrosion build up in seal grooves. Owner had sprayed in WD 40 and levered the very stiff pistons back in, with the pads in. Result was seal lips ripped off and pads bent.

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JJ ,front pads on my Mont squeal like hell when they get wet . From then on that continues until i remove them and clean them up. The noise isn't high pitched either , it sounds like a wagons brakes,bloody awful.Vibrates right through the bar's.

The rear is nowhere near as bad though.

I haven't lost the lever or noticeable performance either.

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That'll be the floating disc collars, I had a similar issue, took them off and put some silicone on the surface that has contact with the disc mounts, sorted. I don't really rate Braktec's quality, I think it's a bit hit and mis. It's a shame brembo don't make brake parts for trials.

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