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Help with Brakes on Motorvation side car...PLEASE!!!!

Hello Everyone,
Ok I am going to give you a quick run down of what I have going on. I bought a Motorvation sidecar and have finally gotten around to bolting it to my 2004 Fatboy. The problem I have run into is the brakes. This system requires me to Tee it into my rear brake on the bike. I have done that but cannot for the life of me get a firm pedal at all. I have bleed many of brakes on all kinds of things and cannot get this handled. I am now thinking it might be the master cylinder size. I am not sure how many pistons my fatty has in the rear caliper since i am to lazy to take it off but i know the side car has 4 pistons and the line going over is 80"+. I think i have narrowed this down to the master size being to small to move all of these pistons? Am I on the right track? Would a touring model master work. I don't need anything aftermarket and chrome. If anyone can think of any other things that could be the problem i am up for suggestions. I have tried gravity feeding, power feeding with a power bleeder, the ol syringe in the bleeder and reverse pumping fluid, and other things. I am lost! Please someone help. :o:-(

i have a motorvation spyder on an 07 sportster and the brakes work fine. i think just keep trying it should work.

When you "tee'd" your connection, did you use a perportioning valve? I may be talking out of my azz as I don't have a brake on the sidecar, but I have read that a perportioning valve is needed as well as a quick disconnect.

Oh and welcome to the slightly off-center world of sidecars!

Some times it can simply be hard to bleed brakes when you are adding a brake to a bike that was not intended to work additional calipers. One thing I have done is a bit backwards from how things are normally done. What I will do is open the bleeder screw. Then push down the pedal, once the pedal is down then tighten up the bleeder screw, let the pedal back up and repeat. My "theory" on why some time it can be hard to bleed is that we end up "percolating" an air bubble. With this method the velocity of the moving fluid is greater and can help get the bubble to move along. Of course once you have done this method a few times you then go back to the normal way of bleeding the brakes. I have had this work when nothing else has.
Jay G
DMC sidecars

Jay G DMC sidecars 15616 Carbonado South Prairie RD Buckley WA 98321 866-638-1793 Hours Monday - Thursday 6-4:30

Interesting topic. I had the same issue on my Valkyrie. Just didn't like the feel of the brakes. Tried all the bleeding methods mentioned and finally gave up. Disconnected the quick connect. If the quick connect is disconnected I found the hard way that the fluid left in the sidecar brake system will expand from any heat generated and lock up the hacks brakes. Couldn't figure out for a couple of minutes why the rig was pulling right.

The problem with humanity is: we have paleolithic emotions; medieval institutions; and God-like technology.

I might not be getting enough stroke in the pedal to remove the air. The motorvation bracket goes right under the pedal about 2 inches. What do u all think?

Attached files

If you can't fully operate the brake, something needs to change. Even if it were working fine, if there was some problem and you needed to use the last bit of travel for an emergency stop, you're screwed. Don't fool around, move something. That's too pretty for the solution I used. I have a beater bike I got for $500, I just bent the brake pedal a little.

That can be a serious problem. You don't have much stopping you, and if you don't have a 3W brake, you absolutely rely on it.

I can get just the bike itself to bleed with the brake pedal and bracket like it is. Its when I add the sidecar that i cant get it to bleed before my pedal bottoms out on the bracket. When I bleed just the bike i cant stand on it to get it to hit the bracket.

might need to get a bigger master cylinder.piston size for more volume in fluid , and a perportioning valve