Top kart brake issues any help


(Mateo I Perez) #1

Make and model of chassis
2011 top kart flash
I need help with
Brakes
What I’ve tried so far
Replaced seals in master now that working but the calipers are getting fluid but zero movement.! Also what other brakes work mcp i have seen much smaller bolt spacing. Thanks
20181220_183204|375x500


(Tony Zambos) #2

First, the seals in some master cylinders are directional but have no idea about Top Karts. Second, some brake fluids will take the paint off the frame and know what type you should have in your system, i.e. Dot 3, 4, 5 5.1.
You didn’t mention that you’ve bled the brakes, so start there. Bleed them until you’re sure there is no more air in the system, them bleed them one more time. The pistons in the caliper also have seals and you may need to replace them as well. If after bleeding the system and there is still no movement of the caliper pistons, remove the pistons. Look for hardened seals, debris and corrosion.


(Mateo I Perez) #3

Sorry yes i bled system was getting all the air out of system. Getting pressure from master as can see fluid shooting out bleeder reservoir also getting fluid flowing out all 4 bleed ports and sealing back with brake pushed down but still zero movement.


(James McMahon) #4

Just so I understand… With the system sealed do you you have

Some\little movement at the master cylinder, but none at the caliper?
Full range of movement at the master cylinder, but pads are not moving?
Something else?

Shoot a quick video of what you’re seeing with the brake system right now perhaps?

How did you go about bleeding the system?


(Mateo I Perez) #5

I will shoot video for sure i have full functioning master i believe at least. Zero movement at caliper. Master plunger was locked up took apart cleaned and replaced o rings now moves as it should. Bled by attaching bleeder pumping fluid into system holding brake full on and cracking the bleed screws one at time got fluid flowing through.


(Mateo I Perez) #6

I didnt get video but the caliper rubber cups pictured are very loose as well as the metal pistons they dont have the ability to push pads in as they are threaded to adjuster pads they move with no resistance but when i put my finger and pull brakes fluid comes out from the back.


(Mateo I Perez) #7

The mounting bolt holes are 3.25" center to center is there another brand of brakes uses same mounting distance.


(Tony Zambos) #8

Here is a link to one of Top Karts brake caliper pages, https://shop.topkartusa.net/collections/brakes-components/products/adult-brake-caliper
The side view looks similar to yours. If the pistons you removed show no damage and the bores for the pistons are smooth, I’d suggest getting the rebuild kit that has four pistons and four pump seals.
But what I see is the piston bores are not smooth. For your safety and the safety of others, suggest you purchase a new adult brake caliper from Top Kart or other retailer. Also get a new set of brake pads. Everyone will be safer, your brakes will be more reliable and your stopping power will improve.


(Tony Zambos) #9

And before purchasing a caliper, take some brake cleaner and wipe off the rotor. Check for cracks and wobble.


(Mateo I Perez) #10

Thanks that what i been trying to do but unable to find calipers with same bolt pattern.


(John Leah) #11

Going out on a limb here but your pics are not too clear so apologies if I’ve got things wrong.

The caliper cup seals look to me to be wrong way up. The flat face should be to the flat face of the metal piston with the bored end of the piston against the backplate of the pad. That way the fluid pressure forces the seal against the bore.

On your type of master cylinder ( no fluid reservoir above or integral with the m/cyl.) bleed as follows.
Disconnect the pedal rod from the m/cyl. Take out the filler plug. Check that the spring in the m/cyl is returning the piston fully to the front of the m/cyl as fitted to the kart ( operating lever fully back) . Then don’t move the lever until you’ve finished bleeding.
Fill the m/cyl with fluid by hand and get rid of any air by lifting the back of the kart a bit.

You then really need a bleed tower but anything you can rig up to gravity feed fluid into the m/cyl from about 12 inches high will do the job.

So take out one of the top bleed screws from the caliper and run fluid through till it is free of air bubbles. Replace the bleeder screw. Repeat on other side. Do the bottom two for good measure though they are usually interconnected.

Remove bleed tower/ rig, top up m/cyl and replace filler plug. Reconnect pedal rod.
Best situation you have a good brake. Worst, the pads are contacting the disc but you have fluid leakage and the pedal goes slowly to the floor. No way should the pads not move.

Having said all that it may well be that even after a clean up your caliper bores and/or seals are beyond use. A new caliper would be nice but 400 usd!!! I would expect to pay around 140 usd equivalent in UK for a new 4 pot caliper.


(Mateo I Perez) #12

First sorry for bad pics! Oh shoot so the seals as of now are not flat side in. But they should be? the pistons were flat side in but the seals need to be as well? Also should the pistons simply fall out or should they be press fit?


(John Leah) #13

The flat side of the seal should be towards the pad& disc/rotor . The flat side of the piston should point away from pad& disc/rotor .

If there are no seals on the pistons, then they may well just drop out.

It’s an unusual setup, normally the seals are in grooves in the bores or grooves in the pistons . I haven’t seen cup type seals used in a caliper nor 2 diameter bores.


(Mateo I Perez) #14

Ok thanks gonna try this now. Appreciate it


(Mateo I Perez) #15

@d-i-y80 bro you hit it on head! Redid set up on caliper bled like you said it works great! Thanks so much!


(Mateo I Perez) #16

Also caliper was good cleaned up pretty nice actually.


(Mateo I Perez) #17

Sorry rotor not caliper thanks!


(John Leah) #18

Nobody more surprised than me Teo. Cheers!