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Discussion Starter #1
I picked up a really nice 400 4x4 scrambler a few weeks ago. Just been going through all the fluids and maintenance items.
However, the rear brake has never worked. The front brakes worked great.
I went to bleed the rear caliper but got nothing. Took the line off the back and finally started getting oil. Put the line back on and now I have 0 brakes all around. I filled the oil back up and cant find a leak.

The caliper is locked up shut so I'll be taking that apart today, but does anyone have any suggestions?
 

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OIL?? There is no oil anywhere around the brake system. If you put oil in you'll have to flush the entire system.
The rear foot brake is mechanical on that machine and is only considered an "auxillary" or helper brake. The hand lever is the primary braking system on a Polaris machine and applies both the front and rears hydraulically. If the pads are good in the rear caliper it probably just needed to be adjusted.
Once you removed the brake line and allowed air in the system it will need to be completely bled.
Getting the pins out to replace the rear brake pads can be a chore.
Good luck and keep us posted.
 

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Discussion Starter #3
I wish it were just find the leak. I'll keep bleeding it but it doesnt seem to be making a difference at all.
I pulled the rear caliper apart. The piston was seized up so i got it all apart, lubed up and back together. When i pulled the lever on the bars you could see the rotor fluttering around like it was being touched. But i never could get the pressure back.
 

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Discussion Starter #4
So for fun I took the front right line off. Everything else still solid not leaks.
I can get any fluid to the brake.

My plan was to go line by line making sure I could get oil out of each one but I already cant get oil out of the first.
 

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Discussion Starter #7
Welp, got it all figured out.
I took the reservoir / cylinder assembly off, put a tube / funnel over the brake line, filled it up and went bleeder by bleeder.
Sure enough I got to the front left and nothing. Couldn't get any oil at all. Took the line off and nothing is getting through there.

Better yet, when I took the line off the block, basically nothing out of the block. So it looks like all the brake lines are coming off tomorrow and getting cleaned or replaced.
 

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Discussion Starter #8
Well, I spoke way too soon. Got the line fixed, the block cleaned out and other lines checked, filled the lines, installed the master cylinder, and still nothing.
If you hold your finger over the exit port on the MC, it will build up enough pressure that it will squirt fluid a few feet.
Also though, when I release the lever if pulls suction against my finger, is that ok?

I'm really at a loss.
 

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When you cover the port in the MC with your finger and release the lever, it should suck against your finger and suck fluid out of the reservoir to replace the fluid lost when you squeezed the lever with no line attached - that's the way it's supposed to work - if it's not sucking fluid out of the reservoir, clean the pin hole in the floor of the reservoir so fluid can get into the MC bore when the piston returns to the home position when the lever is released.
 

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Discussion Starter #10
Do they make a rebuild kit? I cant find one.
I will try cleaning the port out tonight and checking travel of the piston, before / after
 

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Discussion Starter #12
Thank you very much. Where do you go to get that number. I checked a number of places and never could find it.

What's the step to get the piston out? There's a little rubber ring on piston on the back where the lever pushes. Carefully take that ring off then there's a snap ring behind it?
 

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I got the number on the Polaris parts website

Exact procedure to remove the parts? I don't know - I have to see the construction and then determine the plan of attack
 

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Discussion Starter #14
The master cylinder fixed the issue completely. Just very strange since it worked before I bled the rear brake. Maybe the extra movement of the lever (beyond where it's been in the last 15 years) was the culprit. Either way, thank goodness that is over.
 
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