Brakes

[Biglee 123]

Hi all going to tackle the brakes back and front on my kymco400i never done them before always had a shop do them but now really hard to get an appointment they are approx a year old they speak a bit on the rear only and the pistons rear and front need a good clean any advice on cleaning and lube and any dos and don'ts much appreciated thanks all

[Stephen]

Roger(road runner)has a Kymco 400,i know he does a bit of tinkering himself,as far as i know he pops on to the site regularly so may well give some advice.....

Steve

[Biglee 123]

Ok thanks

[EvilRacer329]

Brakes can be easy or tricky, depending on how far you're going, what you're doing to them etc. At the basic end you have a simple pad swap, at the extreme end you have caliper rebuilds and brake line replacements. Over the years I've accumulated any number of brake-specific tools to make these jobs easier, but you can do the basics with:

- Whatever wrenches/spanners you need to remove your bike's calipers from the forks/swingarms
- A can of spray-on brake cleaner
- An old toothbrush
- A green supermarket scouring pad
- Cable ties

This assumes that you're note removing the brake lines, as that would mean you're draining and refilling the braking system. That's a good idea, and a fluid flush should be done at least every two years, but that's for another day.

Basically, unbolt the calipers, pull out the brake pads and clean them up with the scouring pad and the brake cleaner - including the friction material, you'd be amazed how much crud gets caked in there. If you're changing the pads (EBC HH-spec are my favourite), skip this step. Pump the shiny chrome brake piston out a few mm by pulling the brake lever - don't let them go to far or you'll pump them out all the way and let air in, requiring you to bleed the brakes. Then, use your brake cleaner and toothbrush to clean the crud off the piston as best you can - if possible, grab the piston with your fingers (NEVER a pair of pliers) and rotate it to get to all sides. Hopefully it comes up pretty clean, no major marks or pitting. If not, you might need to disassemble the calipers and attempt to polish them up with scouring pads or even autosol, or perhaps even replaced if they're really bad. If the seals get pulled out when the pistons come out, then you're looking at a rebuild and almost certainly new seals.

Assuming everything went well with your quick-clean, push the pistons back in as far as you can, slot the pads back into place, then bolt the calipers back on to the brackets. Take copious photos as you go to make sure you're reassembling correctly. Then pump your levers again until the pads grip the wheels, always test while rolling back and forth in the garage before you go for a ride. For bonus points, pull the lever all the way back to the bar and hold it there for a few hours with a cable tie to fully seat the pistons to the seals, you'll be amazed the difference this makes to initial bite.

It sounds scary, but once you've done it you'll see that it's not so complicated. Take your time, be methodical, and you'll be fine.

Nick

[Biglee 123]

Thanks nick I remove the caliper from the forks put everything except the brake pads and pistons in my sonic cleaner 30 min later all came up like new cleaned the pistons with the toothbrush and put a smear of copper slip on the pistons worked them in and out a few time then reassemble everything they seem to work a treat now done back and front

[Rocketman122]

@Biglee 123

you know what youre doing. its obvious. I too use some copper grease on the pistons to let them slip in and out smoothly. I also use a super thin layer on the metal slides the pads sit in. but very little so nothing spray on the rotor. I also use a bit on the bolt that goes through the pads. and just the smallest drop of locktite blue. but I always make sure the threads are clean on both sides.

good job man!

[Biglee 123]

Thanks I made the sonic cleaner with a peanut butter jar and my sander worked a treat

[EvilRacer329]

Hey guys...did you say you put *copper grease* on the brake pistons? From my understanding, that's a *really* bad idea. Some mechanics I know won't even use copper grease on anything anywhere near the brake calipers, because of the risk of it getting to the brake seals themselves. Copper grease literally contains tiny pieces of copper, which can shred the seals over time. Ideally, you use red rubber grease, which is safe to use and sticky as all hell. If I were you, I'd strongly recommend pulling it all apart again and getting that copper grease out of there ASAP. Hopefully it hasn't gotten up-stream and contaminated the master-cylinder seals or anything in the ABS unit, if you have one.

Nick

[Sylar]

I just put new pads in my Cruisym 300. Dealer wanted £89 for front and rear. Ebay Kyoto pads front and rear £20 76. I used brake cleaner in the caliper . Copper grease only on the rear of the brake pad and only a light smear. Never heard of anyone ( until now) putting copper grease on caliper pistons.

[Rocketman122]

I use an almost imperceptable light layer of grease on pins and on the metal spring snap in guide plates. one drop of blue threadlocker on each thread