[alaskan6667]

New to the forum. I have a 2015 UForce 800 and the breaks went out last hunting season going down, of course, one of the biggest hills we were hunting near. Now fast forward to this spring.

1. Rear pads were worn to the disk.
2. Front pads (originals from 2015) still look new. No wear at all it seems.
3. Peddle goes to the floor.

Here's what I've done and checked so far.

New calipers on all four corners. Replaced rear rotors. Replaced master cylinder.

Break pedal still goes to the floor. No pressure build up front or back. I've bled them forward and reverse multiple times. I get no movement at all. I've adjusted the break pedal numerous times into different positions. And still nothing. It's showing no signs of leaks anywhere, nor any swells in the lines. As far as I can tell, the front breaks haven't worked since new. There was very little sign of wear on the pads or the front rotors.

And this is my dilemma. The nearest dealership is 6 hours from home in Fairbanks, AK. Is there anything else I could check or look at before a long journey and prolly not having our machine all summer?

I've done tons of break jobs on wheelers and autos in my life, but this ones got me stumped.

Thank you for any advise or comments that might help me figure this thing out. Love our machine, just needs breaks!

[NMKawierider]

That's sure a strange problem. I know this: It's almost impossible for one or two people to bleed these the conventional way. It has to be with either power-bled or back-bled from the calipers. Also, many CFMs MC return ports will not open to the reservoirs until the piston is near 100% return. So ensure that you do have some free play between the peddle and the rod...and that the master's piston is coming all the way back. Also...there were some that found the brake lines switch on some models so ensure the lines go to the right places. And lastly..there have been tones of bad new CFM master cylinders. Some were assembled without some cups so...it may not be you at all.    

[alaskan6667]

I appreciate the advise NMKawierider. I replaced the MC already and that hasn't worked. Then I ended up buying the entire break system, ie.. calipers, lines, MC, because it was cheaper through alpha sports than buying just the calipers. So maybe my new MC isn't working and is one of the bad ones. The system came with an new MC also, so maybe tomorrow I'll put the other new one in and see what happens. Thanks again.

[NMKawierider]

Yeah..the reality is.. if you got all the air out..even most of it, and there are no leaks, and the peddle still goes to the floor with no pressure building..its likely a bad MC.

[doug80638]

It sounds like your front brakes were never being used and the back brakes were doing all the work (yikes!). Stuck calipers or jammed brake pads could cause the front brakes not to function.
If they weren't functioning for 6 years, it was probably a good idea to swap them out (though I prefer to test anything before replacing).

A failing brake circuit (front?) in the MC is usually the result of air trapped between the two circuits (improper bleeding) , bad MC seals, or obstructed ports.

Did you bleed the new MC before you installed it? This is a procedure that is often skipped and can  cause of lots of frustration down the line. Air in the MC can result in damaged seals after many cycles.

Since you've replaced everything, I would start from square one and re-bleed the master cylinder before hooking it up to the brake lines. Use clear tubing if you can to assure all the air is out.  Then bleed from the master cylinder down to each caliper.

Reverse bleeding can bring air back into the MC and defeat the exercise. It's better to reverse bleed the caliper and line before you connect them to the MC, and then bleed down in the normal fashion ( pump the brakes, power bleed, vacuum bleed). And if air gets into the MC during the process (failure to keep reservoir filled), wash, rinse, repeat.

Good Luck!