Rear Master Cylinder

[400exc]

Does anyone else have problems with their mast cylinder for the rear brakes losing prime? I have heard of one guy that had his go bad. I will prime the system and in a couple months it loses its power. Probably the mast cylinder seal inside?

[Quinn4]

Yes mine was defective from the factory, I had to call Can-Am to get the dealer to do a warrenty repair. Also my brake pads in the rear were shot after only a few rides.
It's not a huge deal to fix I may be able to find the part numbers and info from my repair if you need it.

[TNT]

You own a 08, if you have not rebuilt the MC in a couple years that may be your problem. There are seal(s) and a spring in there that wears. Also cut a slit in the reservoir cap boot so air can escape and not vapor lock. Run DOT 5 fluid. Make sure the gap between the lever and MC is set correct. Look at the manual.

[400exc]

If you can, find those part numbers and what i need if you could! Is it hard to work on and expensive?

[TNT]

You'll need a boot, two o-rings that fit on the master piston, and a spring. From the boot to the set screw that sits up against the hook(attaches to break pedal) is 3.65 in. Might as well replace the break pedal spring too. It's easy especially if you ever rebuilt your car MC or wheel cyl same deal just put new seals and springs in place, it should be cheap less than $20-$30. Go to any dealer ask for a rear MC rebuild kit they can pull up the part #'s from the diagram. Go to thier shop ask for a copy of the procedure in the shop manual. You may as well rebuild your front too, it's probably worn too. There are more line seals/washers might as well get the dealer to show all the break seals, washers, springs, and replaceable parts and replace them all while your at it. You can do this yourself it's easy...if you never worked on brakes before it will be well worth the experience vs putting it in the shop. You need help I am always here. :D

PS: I just redid my toy hauler 6 wheel breaks/bearing's completely, what a job! Electric breaks I knew nothing about but learned alot doing it myself and I was assured it was done right with high quality parts. $1500 job I did for less than $500. :cool:

[400exc]

When you say dealers do you mean Can-am dealers? Or could I possible go to a carquest or something and pick up the parts? I have done a lot of brake work before so none of this is new to me. Haha. But thanks for the info! Greatly appreciated. I might try and prime the system again and see how long it lasts. I am sure though the seal and spring needs replaced. Thanks again for the info!

[Quinn4]

You shouldn't have to pay for or buy anything.
I went to my can-am dealer and told them this was a bunch of B.S.
Then I called the can-am customer support and told them I had a 1993 300ex that never gave me as much trouble as this 08 ds450, that got their attention and can-am paid for everything.
This is a defect and should be fixed for free.
Just my $.02

[TNT]

I would think if he had a factory defect it would not take a couple months-years of riding to show up, sounds like the seals and/or springs are breaking down over time, but if you can get the factory to own up all the power to ya!

If they deny warrantee work and there is no recall I am aware of, determine normal wear I would use the OEM(CAN-AM) atv seals, washers, and springs, that are designed to thier system, unless your really good w/brakes and know how to redesign w/car parts.

Try and bleed out the MC then the caliber.

Good luck! :D

[525outlawrider]

Can am PN#705600763 about $21.00

http://www.cyclepartsnation.com/pages/parts/viewbybrand/4/Can-Am%28Bombardier%29.aspx