Hayes Nines Disc Brakes

[Mark31385]

Hello everyone,

Looking for abit of help please, after almost running in to a transit that pulled out on me today whilst doing 35mph on my MTB and grabbing the front brake and feeling it slip in the pads, so had to dive behind the transit.

Anyway, thought i'd best change the pads on my brakes, Hayes Nines Hydraulic Disc Brakes, went to the shop bought front and rears, £18 each lol

Then when got home thought i'd fit them, so removed the old pads no problem at all, and went to fit the new pads, and on both of them the pads are touching each other so obviously i can't get the wheel or disc back on, so put the old ones back on for now (swapped fronts for rear).

Never had to change hydraulic disc pads on my mountain bike before, so it's a new territory, am i just doing something wrong or what lol.

They are the right pads and fitted as the old ones, but no room HELP PLEASE lol don't fancy entrusting them pads for my work commute tomorrow

[tyefi]

With the old pads still fitted just use a large screwdriver or other similar instrument to gently push the pads slowly apart, i.e back towards the caliper. Then fit the new pads.

[Mark31385]

Hi,

thanks for the response, i tried that but the old pads just seem to return to the original posistion when i remove the spanner, or am i not forcing the pistons back enough, it's almost like there might be too much pressure

[tyefi]

If that's happening the yes you may need to vent the pressure before pushing back on the pad/caliper piston.

[Mark31385]

Please explain how lol it's the first time i've had to do this, as never had hydrolic discs before

[tyefi]

OK i'd wrongly assumed you had previously opened the reservior at some point in the past to add fluid, that would explain the pressure you mentioned. As you haven't had the reservior open there shouldn't be an issue pushing back the calipers, it's a closed system.
Not sure if this helps?

[Mark31385]

Thanks for that,

So basically open the reservoir on the master cylinder on the brake lever then push the pistons back some fluid will come out, reseal the reservoir, new pads in and jobs a good one?

I'm guessing lol

[tyefi]

Yes... well that's what i'd do with my avids or shimanos if i had the same problem, not that i have had that particular issue before.

If you are having trouble pushing the pads back, it is possible some air has leaked into the system, that too might explain the less than stellar performance you experienced. If the brakes are still poor when the new pads are in, and have gotten past their bedding in period, you might want to look at bleeding the system.

I think the fluid will be DOT3/4 so it's an idea to make sure you have a rag near the reservoir in case any should spill over, it's corrosive.

[Mark31385]

Thanks for that, finally got to the bottom of it, as the pads were partially worn, lots of dry sand and mud where i ride, and hard braking, when i had it serviced they bled the brakes for me then so more fluid was in, quick phone call to the shop and they told me to undo the bleed cap to release some pressure a few drops of fluid came out, did it again, now the pads are in and working fine when i looked at the old pads, they were really worn......but now braking is very good again

[tyefi]

All makes sense now! Glad you got it sorted!

[Mark31385]

Yep got to test them, coming down a steep hill on my way back from work got to 37mph but didn't dare go faster considering the weather, very bad each rain drop felt like hail and the wind was throwing me of my line and causing me to be constantly leaning to one side........half way down i was thinking is this a test for the brakes or a test of balls hahha anyway stopped me no problem at the bottom......

Don't suppose you have any tips on weight loss on a bike do you, already done the wheels and tyres, my bike weighs in at 13.4kg but looking to loose about a kilo and a half of it

[tyefi]

I'm not an expert, but outside of the tyres and wheels you've already looked at, to lose another 1.5kgs maybe a tough ask.

A carbonfibre fork might clawback 500g or so, a lightweight saddle, cutting the used portion of the seat post, and some new bars might be good enough for another 300-400g. Beyond that most of the components can be replaced for lightweight alternatives, but you're looking at small weight savings.

Keep in mind that 500g reduction might cost a lot, but will have very little effect on overall performance.