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Mostly Harmless
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Discussion Starter #1
Okay, I've been fiddling with the brakes on my Predator for over an hour, and I still have come to the conclusion that the problem is too much residual pressure from the master cylinder.

I came to this conclusion after removing the slide bolts, and in their place, putting in two 1/4" diameter regular bolts (just in there loose so the pads didn't fall out when I pried 'em apart). Then I jiggled 'em so they would loosen up so I could spin the hub. Next, I squeezed the brake lever. Again, the pads held the rotor tight as ever. I could even remove the slide bolts or my little 1/4" test bolts and the pads remained stuck in place, even when turning the hub.

That tells me the slide bolts aren't the problem. It's definitely brake pressure that is the problem. When I rattle the pads to make 'em loose so I can spin the hub, it's just a matter of prying them apart slightly. This, I expect, is putting just enough pressure on the piston to make it release -- something it isn't doing otherwise.

Hmmm.

Rob
 

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Back to the caliper design Rob, the internal caliper seal is what pulls (normally) the piston back when you release the brake. It's not doing the job on these calipers. The seal is supposed to grip the piston firmly and as you apply the brakes it will distort toward the rotor. When the brake is released the seal returns to normal shape and pulls the piston back. The other negative lies with the master cylinder in that if we could get the calipers to work properly retracting the pads, without a quick take up master cylinder you end up having to pump the lever to get brakes. A quick take up master cylinder will move more fluid on initial apply so you don't have to pump the lever. The total system design is just not what it could be....
 

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Mostly Harmless
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Discussion Starter #4
powerslider:

I see what you're saying. One of the test I did was to remove the pads and then squeeze the lever. I noticed that when I released the lever, the piston DID pull back a bit. What I don't understand is why it isn't doing that when the pads are in there.

I'm to the point of removing the front brakes, since I don't really use brakes often on the dunes anyway. I'll just have to learn to use the rear brake... at least until we find a fix.

You suppose we could find an aftermarket quick take-up cylinder and adapt it?

Rob
 

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I'm sure there are alternatives out there, Maybe try to contact Wilwood, the brake lever has their name on the bottom of it so maybe it's there design and they can give some suggestions on it.
 

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Hi ROb,

Did you, or your dealer, try to bleed the system and replace the cheap factory brake fluid with some Motul 6?

I understand that will have a very positive effect. I also read that you do need to polish the pad sliders, and maybe lube them with a light coat of anti-seize.

I'm going to check out my brakes later this afternoon, and see how they are. I haven't noticed a problem when riding, but I guess I should check it out on the lift....

Good luck


JJ
 

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Hi everyone,

Well normally I would say it's nice to be a member of the club, but in this case it is definately NOT.

I took a good and careflu look at my front brakes, and sadly I am also a front brake dragger. Mine seems to be dragging just about the same as everyone else on the internet has described. I am going to ry some mods to the system later, including a bleeding with Motul 6 fluid, and a polishing on the pad sliders, as was described on this and several other sites.

I may also take a look at the brake lever mod that Heapster dsscribed in his posting in the atvconnection forum a few months ago.

I'll update everyone as soon as possible...

JJ
 

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Discussion Starter #8
JJ:

I've bled the system out and put in my standard Castrol GT-LMA fluid. I don't see how any other brand is going to make the brakes drag any more or any less than they already are. I didn't notice any change with the new fluid, other than a firmer feel in the lever.

I've already polished my slide bolts and it had no effect. The pads are wearing grooves into the slide bolts because of the dragging, and that's only going to compound the problem.

Any kind of lubrication on the bolts will only pick up dirt and sand and make the problem worse too. I suppose I will try it, but I expect that I will have to clean the goop off after an hour of use.

Rob
 

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Discussion Starter #9
Not yet... the ones that I've found so far that are the right size are too stiff. There are still a few shops around here to check; I just have to remembe to DO it when I'm in the area.

I wish there was an Orchard Supply Hardware (OSH) out here in Reno... they have 'em in the Bay Area and they ROCK. They'd probably have exactly the springs I need.

Rob
 

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Hi everyone,

Thanks for the updates with this brake thing...

I have a thought...My local NAPA parts store has a selection of just about every spring, clip, washer, nut, bolt, pin, etc. that has ever been used in the automotive industy...they may be worth a try for the right size/strength spring...

I'm going riding today to check out my latest carb/filter/jetting combo, I'll check with everyone later and post my test results on my ride today. I'm going to start worrying about and messing with the brakes after the tuning issue is all resolved.

Later,


JJ
 

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I'm thinking of buying a Predator and this brake situation concerned me, so I asked my dealer about it the other day. They told me that there is not a problem with the brakes at all, the problem was that the front calipers we not torqued to specifications when they left the factory. The fix from Polaris was to re-torque all the calipers. I did take one for a ride and didn't notice any problem. The brakes were tight, I got about two turns from each wheel when spun by hand, but this was the first time this machine has been riden. Loved the ride, so it will be the next machine I buy.
 

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Discussion Starter #12
The caliper bolts have nothing to do with this problem so any dealer that tells you that it's related is full of crap. I'm not trying to discourage you from buying the machine, absolutely not. It's a great machine and it'll be even better once Polaris fixes this problem.

The problem appears to develop after the quad has around 20-30 hours on it. I'm still not certain where the problem lies... it's either the master cylinder or the calipers themselves.

I've decided that I'm going to drop mine off at the dealer tomorrow and tell 'em to keep it until it's fixed.

Once again, I'm not trying to talk you out of the machine. I think you should still get it, but if you aren't looking to buy right away, that's good because it will give you time to see how Polaris handles this developing problem.

Rob
 

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Rob,
I wasn't buying his story about the caliper bolts either, because it just didn't make sense at all. I'm definately going to buy a Pred in the next month or two, so keep us posted on this brake issue. I has to be one of two problems, either the caliper seal on the piston is not retracting it back in, or a pressure build-up in the master cylinder. I think its probably the master cylinder.
Thanks,
Rob
 

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I know Polaris is taking care of the brake problems we had... I dont know all the ins and outs of it yet, but they are sending out new parts this week and are aware of the problem.. Ill post more when the parts come....
 

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Hey everyone...... This is what we found out from our Carls Cycles here in Idaho...We took it in for a few minor problems,( gas cap breath hose breaking and coolant res. cap leaking to results of simply hole being too large in the cap)..............Anyhow. the dealer said they tore the entire breaking unit down, and it turned out that the master cylinder may have a defect...(which I think most of you already know).... There is a rubbber boot of flange (not sure which to call it),is folding over in the master cylinder. This is because there is too much space in the master cylinder, causing the master boot to roll over inside the cylinder, applying premature pressure to the breaking system..The dealer warrentied it out with no problems on Thurs. part will be in on mon. They will tear the new cylinder apart, and see if the problem is true on the new one.( to prove if this therory stands true on the new one and if defected,they will have polairs come out with an alterative to correct the problem) The dealer was awesome and very eager to take care of this probelm..Ill let you all know what the end rasults were.................Tina :)
 

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I will..Im crossing my fingers the parts will be in today..
 

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That has to be the best hypothesis I've heard so far. That makes a lot of sense....please keep us posted.
 

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I just got my new Predator Sunday and it has the brake problem as well. Had it coming off the trailer.
 

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Discussion Starter #20
Kev:

D'oh!

Mine's going to the dealer in the morning. I'm bringing a printout of Tina's post so that Chuck (the head mechanic) will know what to look for. With luck, he'll be able to verify the findings and we can then have two enlightened dealers.

Rob
 
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