Big scoot brakes ??

[stevew]

So just doing some preventative maintenance on the Maxsym 400i brakes and i notice that the brakes are a little odd.
What appears to be twin 4 piston calipers is in fact (on the right) a proper 4 piston caliper that takes EBC SFA627HH pads so that's ok so far. This front is linked to the right lever ONLY.
But on the left front (and linked to the rear) the caliper looks like a 4 piston one identical to the right hand side but is in fact a 2 piston caliper. The bottom two piston bores are blocked off and not used !! This is operated by the left lever.

They both look like this;-



When i removed the OE pads from the right they looked completely normal, just like the EBC replacements.
When i removed the left OE pads they had only half the friction material although they used the same metal backplate.

I don't see anything wrong with this set up and it all works well.

So i called EBC to see if they had the "half friction material" version of the SFA627HH pads and they said they had never made them and the standard ones would work ok.
Now this got me thinking (bad thing i know) that if the two pistons are at one end of the pads (the same end as the friction material on the OE pads) will they not wear in a "wedge" shape if i put full friction material pads in ??

[Diesel Dave]

I'd grind off the extra material to match the originals.

From an engineering perspective having a full pad with only one half being compressed would be a recipe for disaster, indeed I've seen this on a Honda 3 piston setup (centre used for the rear brake application only - notice CENTRE). The top piston had seized solid and only the bottom one was being used and it caused the pad to jam on the pins.

How come your changing pads so soon?

Remember the copper grease...sparingly!

[Radagast]

Why did they (the designers) do that?! Awful configuration. I agree with Dave. I will grind extra material, so i try to enlarge a little (a few 'cone' shape hole) the pad's holes to preventing jam pad on the pin because they are pressed by the piston but just in one side.


Or just replace that caliper for another one like the right side one. And both calipers operated by one lever.

[Tranberg]

What designers don't do for aesthetics.

My Guzzi with linked brakes had the same size pistons in both the right and the left front as well as the rear caliper, and relied on three different pad materials to give the desired effect, which could then be messed up by clueless (DIY)mechanics. If only they'd used different piston diameters.

[Capitano]

Why did they (the designers) do that?! Awful configuration. I agree with Dave. I will grind extra material, so i try to enlarge a little (a few 'cone' shape hole) the pad's holes to preventing jam pad on the pin because they are pressed by the piston but just in one side.


Or just replace that caliper for another one like the right side one. And both calipers operated by one lever.

Yep, I'd go for this. Sym should have loads in their vast stocks of spares.

Actually, being helpful for once, a pair of Brembo calipers from a Piaggio X9 or Gilera Nexus might fit.

[stevew]

I'm not changing calipers. The OE set up works fine.
Looks like a bit if friction material grinding is in order.
Not needed ATM but when the time comes

How would you suggest i do the grinding. I have an angle grinder, what discs ?
Or by hand with a dreadnought file ?

[LeVelo]

I'd hacksaw the wear groove all the way down to the backing plate then knock the unwanted chunk off with a cold chisel. Saves making a lot of dust.

If you decide to grind it, a flap disc would be best. Grit wheels load up with claggy materials (like the copper in HH pads) then start to rub instead of cutting, which is no good.

[Radagast]

The metal cutting disc is fine. Take a good enough care of your breathe. The dust of that pads used to be carcinogenic. Use a mask. Don't try to grind it with the face of the disc, that causes many dust, instead, cut a slice thick enough and will be ok.

Remember the cooper grease too advice from D. Dave.
Regards!!

[Radagast]

If you want to file overnight, then go ahead

[davebike]

Don't put copper grease on modern alley calliper use Brake grease or red grease
Copper grease kills modern calliper seals !

Bloody Haynes Joke books !! 20 years out of date