Pre 2015 Tony Kart brake fluid

Folks, can someone set me straight regarding proper brake fluid for older Tony Kart SA-2 rear caliper. Is it DOT 5.1 that I should use?

Also, had a hell of a time trying to bleed the system today on out kart. I have a single OTK master cylinder and the only way I can figure to flush the system is fill the
Master reservoir nearly full and pump brake pedal million times… I can not fill up the lines by doing so… is there a Better way?

You get one of these and it screws onto the master cylinder. You open the valve and gravity does the rest.


At the caliper, you also remove a bolt which allows hte fluid to be pushed through the system.

I get it… but I have a BSM4 master cylinder which only has an aluminum holding tank and no plug to attach the bleeder tower…

Also - guys, I have SA-2(BS6) rear caliper… pretty sure our kart is pre-2014 Racer 401… am I supposed to use DOT 5.0 brake fluid?

I anticipate a struggle bleeding this deal…

Probably for peace of mind use silicone fluid dot 5.0

Tonykart/OTK have messed around with brake fluid spec. over the years starting? with glycol based fluid dot3.dot 4. then going to silicon dot 5.0 and currently dot 5.1 which I class as glycol. The spec in 2014 was apparently Dot 5.0 silicone.

As I understand it, if any brake fluid is going to attack any seals it is the glycol fluids. Dot 5.0 silicon is safe with everything.

However, personally, I doubt if there has been a European kart brake made in the last 20 years with seals that would be attacked by Dot3,Dot4,Dot 5.0 or Dot 5.1 fluid. but…

So, you have a BSM4 master cylinder (Pumper type with reservoir) and a BS6 caliper (Self adjusting, no pad pull off springs ?

Good pics. of all the brakes at www.cometkartsales.com /Tonykart parts.

That system SHOULD bleed normally. Fill up reservoir. Open 1bleed nipple at caliper. Actuate the master cylinder with long steady strokes until fluid comes out of the nipple free of air. Keep reservoir topped up. Close bleed nipple. Repeat for other side of caliper. Done.

But if you’ve done all that and got nowhere.
Disconnect operating cable/ rod at m/cyl and check that m/ cyl piston is returning fully and freely.
Close caliper bleed nipple at end of each stroke and open at beginning of next stroke.

Use a rubber bleeder pipe on the nipple. the type with a plugged end and a slit in the side which acts as a non return valve.
Still no joy.
Disconnect caliper line at m/ cyl and operate m/cyl with your finger over the outlet. Down stroke will blow air/ fluid past your finger, return stroke will pull fluid from reservoir into the bore. Once pumping well reconnect caliper line. Sometimes m/cyl needs ‘priming’

Bleeding brakes is usually a struggle!

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Thank you John. I will get some decent DOT 5.0 fluid and get after it. Appreciate your help!

If there’s fluid in the system I’d advise testing what’s in there first. Unless you’re rebuilding the system with new seals or you can verify from previous owner what they used… because sometimes people don’t use what’s recommended.

DOT 5.1 is “compatible” with both silicone and glycol, but I can’t say if it’s suitable for racing.

A wise person once told me “Don’t ***k with brakes”

That person was very wise! Thank you all for help! Since we have removed the front brakes to adapt our frame for LO206, I have ordered new seals, etc, etc… and will fully rebuild the system and flush/load with OTK Silicone 5.0 fluid. Appreciate you all!

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Thank you all for guidance. Managed to rebuild the caliper and reinstall. Filled the system with purple DOT 5.0 fluid and managed to bleed the system. Today we ran for the first time and after bedding of the new pads managed a very good time at our local track. First race coming up on 5/9 and SRP in New Caney TX.

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