Disc Brakes

[propain37]

So I installed some disc brakes I got from OMB Warehouse and they don’t work at all. I installed them and had the brake fully depressed but the kart kept on moving forward. Please help me out.

 

[Kartorbust]

Might have too much slack or play in the linkage to the caliper. Assuming this is mechanical and not hydraulic, you might not have the lever move far enough to make enough contact with the pads to the rotor. Let's have some pictures of how you have it setup.

 

[propain37]

Here it is

 

[mckutzy]

A couple of things off hand...
You have the caliper hard mounted... That style of caliper has to be mounted in a way that allows it to float... or the rotor....I havent really seen one of these kind much before so Im not too sure offhand on how they do this...

These typicall have to be bedded in before use... so a sanding of the pads to the conture of the disc...also a good cleaning of factory oils and grease of pads/rotor...

They typically are bi-directional... so you can mount it in a fashion to eliminate that bits of extension material for the actuation lever...

 

[propain37]

What do you mean by floated, won’t it fall of then? Also how much should I sand it. I see some copper start to show. And should I sand the disc as well.

 

[mckutzy]

The caliper when actuated pushes the one half toward the other.. If the caliper is hard mounted, as the pads wear, they pull more and more to the one side. Eventually it will warp the rotor, or break somthing..
Mainly it just optimizes braking performance, with the above notation..

 

[propain37]

I don’t have a bracket for mounting a floating caliper (i did some research) can I float it using the bolts I have?

 

[Kartorbust]

Yes, long as the bolts will fit through the holes nicely.

 

[mckutzy]

At first I thought up a system similar to that of a typical car brake..
I made some pins that hold the caliper halves together, act as bolts, but allow the caliper to float on the custom mounting bracket...
At the time I didn't have the proper bracket.. But this is the bracket pin(I didn't finish the bracket)....
There is a bronze bushing that pin rides in.. Bushing was supposed to be brazed to a horseshoe shaped bracket that's mounted to the frame..

 

[jandj]

Don't worry about floating the caliper.
Just let the rotor ride free on the key stock on the axle.
If you need more wiggle room, space the caliper halves.
It's a lot easier.

 

[mckutzy]

There is that too.. Put some hose clamps on each side to limit travel, keep the key contained...

 

[propain37]

Nothing is working. The rotor has always been floating. I had the caliper spaced originally and put an aluminum spacer to touch it. I later removed the spacer and tried it again. I fixed the rotor and then the caliper would tilt when the brakes were applied. I’m going to try to drill another hole into the caliper arm to hold the piece of metal I have more securely. Will let you know if that works.

 

[propain37]

I think it worked but I want to know how effective mechanical disk brakes are. I don’t want to be looking for unrealistic stopping distance.

 

[landuse]

I think it worked but I want to know how effective mechanical disk brakes are. I don’t want to be looking for unrealistic stopping distance.

They should stop you pretty good. Installed correctly they should lock the wheels up (or close to lock anyway)

 

[propain37]

I was wondering cause I had my friend move the kart while I was pushing down on the brake. Kart just continued to move

 

[mckutzy]

I'd check the pads... Look for the wear pattern.. See if they are making a full contact of the surface of the pads to the disc...
I have sanded the pads 3-4 times to get them to fully lock up right..

Loosen the adjuster, put a piece of 60-80 grit between the pad and disc.. Move it about to take off a bit with your hand on the actuator arm to have slight clamp against it..
Spin the wheel a bit to encompass the whole rotation of the wheel/disc.
Do this a few times. Clean with Brakleen, try not to touch the clean parts, aswell avoid the brake dust, as it might be asbestos in it..
You might have to take a slight pass with a sander pad on the disc aswell depending on if there is a glaze present, it should be a matte ever slight rough finish...

When reassembled, Check the effectiveness of stoping at a lower safe speed, in a safe area...
There might be some mechanical losses due to the added pieces for extending the actuator arm..

 

[Functional Artist]

You may be loosing something with that double lever linkage set up.

I would start at the basics. (take the pedal & linkage out of the equation)

Remove your linkage to the pedal & put the kart up on stands.

Activate the caliper lever (by hand) while turning the tire (with other hand)

Is the (movable side) moving & engaging (pushing against) the rotor?

Is the mounted side engaging the rotor?

Can you stop the wheel (turning by hand) with the caliper (activated by hand)?

 

[propain37]

You might have to take a slight pass with a sander pad on the disc aswell depending on if there is a glaze present, it should be a matte ever slight rough finish...

My rotor is completely glossy. How much should I sand the rotor and the pads and using what grit of sandpaper?

 

[mckutzy]

60-80g... What ever cuts the sheen. Just enough to take the finish off, should almost make a mark with your fingernail like a chalk board... I'd suggest using a hand sanding pad... But if your confident you won't dig in the disc, then maybe a power sander..
I did all my discs witha sanding pad..

 

[propain37]

Thanks, how would you recommend to set up my linkage for my brake.