problem with brakes

[sicivicdude]

WARNING! this is not blaster related but I really need to "ping" this off some people....

My wife and I went riding with twostroker99 last weekend and after returning she told me she had had enough.... the front brakes on her prairie have GOT to have something done about them.

Here's the deal, I bought the 1999 prairie ~4 years ago with an entire HOST of issues. One of the many was that the PO had run the front brakes until not only were the pads gone, the backer plates were gone, and one of the calipers had begun to actually eat a piston

To say the least, this guy wasn't a stickler for regular maintenance.

So off to Ebay I went... I found a guy in Minnesota or somewhere who had an entire 1998 prairie 400 front brake system for sale and I won the bid for like $25 or something really cheap like that. It arrived and the system needed some maintenance (calipers cleaned and lubed nothing major...) and I bolted it right on. From the very beginning, the front brake pull was.... harsh. I chocked it up to the fact that it was AWD and just told my wife to make sure she hit the front and rear brakes equally. This sufficed for a while until I found a deal on some ITP delta steel 12" wheels in the correct bolt pattern for a prairie 400 4x4. I soon had a set of 27" kenda executioners on the way! After installing the new wheels and tires the brake action was even worse! Of course, this reaffirmed my thoughts that it was something to do with the fact it was heavy and AWD. Then something happened.... I bought a kawasaki bayou 400 4x4. The bayou 400 4x4 would slide all 4 tires using JUST the front brakes and it was AWD as well. I then installed ITP delta steel 12" wheels in the bayou bolt pattern and 28" tires... it would STILL slide all 4 tires. I maintained both the bayou and the prairie for quite a while and noticed a few differences... the bayou had twin piston front calipers and the prairie has single piston. I understand how this could SEEM to be a huge difference but hydraulic systems use area for a given pressure, not necessarily the number of areas that area is divided over (I understand the principle that *generally* the more pistons the better) and the prairie and bayou calipers seemed to have about the same amount of caliper piston area... the prairie has one large piston, the bayou had two tiny ones. I think the difference in caliper design was due to the fact that kawasaki put 11" wheels on the bayou so two smaller pistons allowed for the smaller inside diameter of the wheel.

I looked for a while at the possibility of putting the bayou calipers on the prairie but the designs really are quite different... and I don't think a direct swap is feasible.

Now, the prairie brake system *seems* to be fully operational... all 4 pads are wearing evenly (not crooked or one side wearing more than the other) and it DOES apply hydraulic pressure when you pull on the handle. I've tried bleeding the brakes several times with no change in handle pull.

What I'm wondering is, if, instead of increasing the area of the caliper, I could reduce the area of the master and "cheat" my way to more pressure. I believe the master cylinder that's currently install is a 14mm bore. I was wondering if anyone knew of a particular quad (or bike if someone knows I definitely can use that!) that had a 13mm bore master cylinders. I know they make them, I have one on my blaster and it makes the brakes MUCH more responsive but the one I have is a donor and I have NO idea what it came off of....

 

[blasterdemon7]

The only real advice I can give is to flush all the old brake fluid out and replace with brand new fluid. Brake fluid likes to absorb moister making the brakes feel mushy . You can also scuff the rotors to remove any glaze. That will help the brake pads bite better. You can also check any of the rubber brake lines to see if there swelling when the brakes are applied . I don't know if any of this will be a help but I tried.

 

[sicivicdude]

The only real advice I can give is to flush all the old brake fluid out and replace with brand new fluid. Brake fluid likes to absorb moister making the brakes feel mushy . You can also scuff the rotors to remove any glaze. That will help the brake pads bite better. You can also check any of the rubber brake lines to see if there swelling when the brakes are applied . I don't know if any of this will be a help but I tried.

I have flushed them several times with NO change in the feel of the brake handle

I've never tried hitting the rotors with sand paper but my and I regularly ride this in mud and water. I'm afraid any small gain that scuffing the rotor might afford will be lost the first time a mushy sandy mess has the pads applied to it.

I am thinking about changing out the brake lines tomorrow and seeing if that makes any difference. Part of what makes me think that it's not brake lines is that both calipers are working evenly and the handle pull isn't "squishy" like you'd expect out of an expanding line.

I did a little research and it seems that the rebuild kit for the master cylinder is the same for 97-02 prairie and 93-98 bayou 400 4x4's indicating that the difference wasn't design of the master cylinder.

 

[Awk08]

have you rebuilt the master ????

 

[slickerthanyou]

I'd have to agree- would seem to be a master cylinder issue.

 

[sicivicdude]

I haven't yet, the original master cylinder was dry when I got the prairie (from the nimrod PO running it until it ground half of a piston away) and I used what I had available (the 98 prairie master I got off Ebay).

I can tell you, I had no trouble at all priming and bleeding the system when I installed it. Other than that, it's a little black hole down in there....

Maybe the next step is to tear apart the master!

 

[slickerthanyou]

I haven't yet, the original master cylinder was dry when I got the prairie (from the nimrod PO running it until it ground half of a piston away) and I used what I had available (the 98 prairie master I got off Ebay).

I can tell you, I had no trouble at all priming and bleeding the system when I installed it. Other than that, it's a little black hole down in there....

Maybe the next step is to tear apart the master!

For sure! There shouldn't be no reason , larger tires/rims, awd, 4wd that it shouldn't lock up!

 

[Awk08]

for the usually $9-$15 i see master rebuild kits going for on ebay, i'd try that before getting new lines,
what pads are in it now ??? semi metallic, sintered metal, organic ???
maybe try a different brand pad too before swapping lines

 

[sicivicdude]

The pads are semi-metallic as I recall.

I'm gonna pull the master cylinder today and check it out. I've pulled a few before and found crud in them but usually when they're crudded up, they don't work at all!

 

[Awk08]

The pads are semi-metallic as I recall.

I'm gonna pull the master cylinder today and check it out. I've pulled a few before and found crud in them but usually when they're crudded up, they don't work at all!

very possible the o-rings and little rubber cup in the master are weak and pushing fluid, just not enuf

 

[sicivicdude]

very possible the o-rings and little rubber cup in the master are weak and pushing fluid, just not enuf

I pulled the master cylinder off and gutted it. Both rubber cups looked great. There was a small amount of rusty crud on the snap ring holding it in but nothing inside. I wiped everything off (just in case) and reinstalled the master. I bled the system and it was right back to the same place it was before. The brake handle pull begins early and get very tight very quickly...

I think the solution is a smaller diameter master cylinder to increase leverage. The master cylinder I have on my blaster is a 1/2" bore (stamped in the side) and it stops GREAT. When I first installed that system I had a banshee 14mm master on it and the handle pull was about the same as the prairie (started early and pulled very hard but stopped only marginally well)

 

[Awk08]

i've had the exact same symptoms a few times, very quick and hard brake pedal action when bench bleeding my gsxr kits, every time it is air in the system somewhere
try forcing fluid up thru the system with a pump style oil can filled with brake fluid and connected with a short piece of 1/4" hose to each bleeder

 

[sicivicdude]

Pump fluid up? What am I supposed to do with it once it fills the reservoir? It's going to spill all down the fender and cover everthing now....

I don't really see how air trapped in the system could cause this, I've bled them SEVERAL times and all of the lines run "down and away" from the master. I'll give it a shot again I guess....

 

[blasterdemon7]

Reverse bleeding is a more reliable of doing it. Air bubbles like to rise to the highest point, the master cylinder.

 

[sicivicdude]

Reverse bleeding is a more reliable of doing it. Air bubbles like to rise to the highest point, the master cylinder.

It makes sense, not arguing that!

I'm just wondering how air could STILL be in this system. I've had this quad for years, bled it several times, replaced whole parts, changed the pads a couple of times. All the while, no change in handle feel.... still tight, still "early" (for what I would think it SHOULD be).

 

[sicivicdude]

I might have found what came with a 1/2" bore master cylinder... but I need someone with a stock one to confirm (cough cough 2good4u cough cough). Just for giggles, I went out and untarped the LT250R frame and looked at the master cylinder on that. Even if this isn't original LT250R, I'm going to be using it on the prairie (YAY!) but I'd like to know in case I ever need a rebuild kit for it....

 

[sicivicdude]

I replaced the 14 master with the 1/2 master and the difference is just like it was on my blaster, night and day on the handle pull.

The stopping power already feels stronger but the main difference is, it stops moderately well now with hardly any effort on the handle.... Like Awk says about the CR style EZ pull clutch handles, with one finger!

 

[slickerthanyou]

Hey bro, I was thinking about this today, I see that master helped but Have you changed the brake hoses or are they hard lines? I had an issue once with mushy feel and it happen to be the hoses. I know a little late but better late than never!

 

[sicivicdude]

Hey bro, I was thinking about this today, I see that master helped but Have you changed the brake hoses or are they hard lines? I had an issue once with mushy feel and it happen to be the hoses. I know a little late but better late than never!

I have another set of rubber lines but no braided lines I can try.

 

[Awk08]

rebuild the 14 master and stick it on the lt, bet it works !