Can anyone walk me through the front or even back system for a early 90's maybe even a late 80's Trail Boss 250 2wd? I did some trading on my Xplorer 400 that I just did an engine swap, and ended up with this little ATV that I'm going to try to fix the brakes and sell. I think it's actually missing a good majority of the front braking system, but not knowing these older systems very well I'm not really sure what I need to source from the salvage yard and ebay.

I wouldn't be so concerned with the front system, but the back brakes suck pretty bad too and are hit and miss due to a **** down my right foot, so it's really not safe. Other than that is seems to be like a pretty descent little 2-stroke quad... for being 20 years old.

Thanks in advance!

 

Dont know what your missing on the front,but I can help on the rear. The rear brake is mechanical and does tie into the front hydraulic brakes and most of time if the pads are still decent and the caliper piston isn't frozen, adjustment is usually whats needed. If the brake pedal moves ok,just loosen the 7/16 locknut behind the black **** on the caliper,turn the **** in until the brake pedal bottom is about a 1/2" from the floor board when pressure is applied and tighten locknut. Then try and see if rear brakes stop machine. Had a bunch of the older ones with the old red handled hand brakes that sucked and leaked after a few years. A lot of customers didnt want to spend to up grade the master cylinder assy and just used the rear mechanical brake( if its working good will lock up rear tires! Try this and get back to us! CLEAN old 2x4 250,looks like its missing recoil cover though?? As far as front system the master cylinder is the main culprit on these models,not worth trying to rebuild(corrosion usually inside) usually wouldn't build up pressure. Plus check front pads if worn thin and if caliper pistons can be pushed in and not frozen! Sold a lot of these old atvs and a lot are still putting along. They would run on gas that would make a Honda puke!!! OPT

 

Thanks OPT! I'll do this and get back with everyone. At a glance I suspected the front brakes were gutted due to the reasons you stated... cost to rebuild, so I'll just focus on getting the rear ones more consistant and be done with it. I'm currently searching for a recoil cover, but they seem a little pricey on Ebay. Going to check a couple local yards and see if I get lucky there.

 

old polaris tech, would you mind giving me your input? I have a 91-92 trail boss and when I bought it the rear brakes were completely missing. and help with where to find find a used set or how to install would be much helpful. Also when i try to shift into H-L-R-N i get a grinding noise, when in neutral should the shaft coming out of the gear box be spinning? (essentially the shaft would be connected to the rear brake system i would assume. Thank you for your help!

 

91-93 used the same rear caliper and not cheap,especially for a new one.OEM Rear brake Caliper 91-96 Polaris Trail Blazer Scrambler Trail Boss Big Boss | eBay Even a used one that looks like crap is commanding high dollar.1990-1993 Polaris Trail Boss 350 Rear Brake Trans Caliper K14 | eBay 1910073 is what the part # changed to,but you might keep a look out for a 1910046 caliper that was the original part number. As far as the gear grinding,check that the belt is the correct 3211077 Polaris belt and not an aftermarket one that's too tight. That could cause the rear clutch to turn and cause clashing trying to go into gear.

 

Mr Oldtech, I have gone through all the calipers, brake lines and master cylinder on my 250 Polaris 1993 trail boss. I believe I am almost there but cannot get the oil seal that goes on the piston in the master cylinder to go back in without rolling the oil seal back the wrong direction. Do you have any advice for me please?