[Amsoil guy]

Good morning all, we have a 2023 ZForce 950 EX and I have been batting braking issues pretty much from day one.  We have had it back to the dealership and they replaced the master cylinder, then they bled the brakes again, and the last time they said it was due to worn wheel bearings causing the caliper to not engage correctly.  I gave them the "do I look stupid look".  The machine at that time had 400miles on it, it now has 830miles and the wheel bearings are not bad.  However, the dealership won't do anything else until we replace the wheel bearings.  So, I purchased another new master cylinder, bled the brakes, and I had good brakes, until I backed up.  The machine moved 50feet and the pedal went right to the floor.  3 pumps and I have brakes again.  Drove around, brakes worked fine, until I backed up again, then right to the floor.  Again, 3 pumps and brakes were back.  It acts like the calipers are going back in??  It reminds me of when you put new brake pads in your car, you have to pump them again to get the calipers to engage.  I don't understand why it only does it when I back up.  And of course the dealership can't explain it and they did experience it as well.  No leaks in the system.  Has anyone else experienced this?

[NMKawierider]

I have not experienced anything quite like that although on other machines some odd things have happened when changing the rotor's direction of rotation when applying the brake but that's usually because there is either something wrong with the caliper mount or slide..or for some reason the rotor changes position..usually because of a bearing or hub problem. Are you sure they installed the pads correctly? Might pull the caliper and see if there is any movement of the rotor on the hub or bearing...also check that the axle is torqued correctly. Loose stuff is common with CFM.

[Amsoil guy]

OK, thanks.   I will give that a shot.  I will update with any information.

[NMKawierider]

Look for any not only side to side movement but in and out. That would push or pull the rotor to depress the pistons in and cause what you are saying. Really check that axle nut.

[Amsoil guy]

All axles were tight, I replaced the wheel bearings, they weren't bad, but there isn't much grease in the factory ones and I upgraded to a better bearing.  I still loose the brakes when going in reverse.  Not every time, but most of the time.  pump them 3-4 times brakes are good.  I haven't lost them going forward, it only happens when in reverse.  I am a lot loss with this.  I've never had this issue before on any vehicle.