Hello

Have an '86 TRX 250, bought a new master cylinder and put in new brake pistons, new rubber and I still got nothing. Bleeding just seems to be a waste of time at this point. The handle is easy to push with no resistance.

Last thing is the hoses. I seem to remember someone talking about hoses stretching and giving way over time.

Is there some way to check if my hoses are the problem?

Thanks

 

Try an old trick some have done,including me.Helps if the master cylinder is "primed" first. Clamp off the brake line close to the master cylinder with vice grips and see if the master cylinder will build up pressure,releasing air bubbles from the reservoir. Release the grips and start at the far back bleed screw and work your way forward while pumping the lever and holding it tight when you loosen the bleeder valve.Add fluid as it goes down in the reservoir. An extra pair of hands help on bleeding.May take several attempts to build firm pressure at the lever. If this doesn't work,then the best way is to use a vacuum brake bleeder. A lot of auto stores have "loaner" tools like this.Plus some are cheap enough to just go ahead and buy.Vacuum Pump Brake Bleed Kit | AutoZone.com

 

OK, I"ll try that. I actually have a brake vacuum.

One thing I tried was putting my finger over the return hole in the master cylinder and pumping it with the bleeder(s) open. It seemed to improve the volume of brake fluid that was coming out of the bleeders.

Then with the bleeders closed I did the same thing, and after pumping a few times, I took my finger off the hole and a large amount of brake fluid returned back into the cylinder thru the hole from the built up pressure. I would have thought that would have pushed the pistons out but it didn't.

I'll try clamping tonight.

btw, thanks for your continued support on here - I see where you comment on many threads and your input is very valuable to novices like me. I currently have a TRX350, a TRX250, a LT230s, a LT250EF, a Sportsman 400, a Big Red, an ATC200x and a 300ex. I'm just a sucker for older single carb quads. I'm always working on them and always running into issues that I have trouble diagnosing, even with service manuals.