[Ironman19t]

Ok new to the forum here been building dirtbikes for over 20 yrs but I'm having issues I've never seen before. I have a medina mini with a piranha 140 motor bought it yest rear brakes would not lock up the rear tire figured it had air or a bad master cylinder. So I decided to flush te system and flush out any air. So once it all gravity bled out it will not build pressure at all the rear caliper wil move but then suck right back in?????????

on to the front they were just sponged figured I'd work any air out popped the bleeder pulled in on the lever tightened the bleeder ad let go of the lever it did no come back out it stayed in and came out slowly after about 10 mins guessing bad master but y did it work before I bled it I'm flustered never had an issue with brakes evever any help would be greatly appreciated

thanx rich

 

[crazyj23]

Look up the rocky mountain atv brake bleed video on youtube and follow instructions. If that doesnt work then I don't know

 

[thumperman450]

Make sure you had the reservoir cap off when bleeding

 

[DGA]

I take the calipers off and lift them above the master cylinder, and make sure the bleeder is the highest point. Mkae sure you have a spacer between the pads to replace the disk width.

 

[txkawboy]

...I bot three bikes from them a few years ago, and you just might have my problem. The midsize Pitster Clone was/is simply superb, and the two 10" bikes are very good themselves overall, right out of the box neither had ANY rear brake---and I tried everything. I have been riding and wrenching for 30yrs, and it had me stumped, until I finally realized that the brakes on these china bikes are non-floating---which means that ANY misalignment in the relationship of the caliper/pads/disc will cause the disc to bind/drag. Or worse, in my case, not drag/touch the disc at ALL. In these two "Pitster SX90 Clone" situations, the binding was caused by some mis-manufacturing of the swingarm. I made spacers by slowly adding thin shims and reinstalling the rear wheel, until I had built up to the exact thickness needed to ensure perfect alignment of the caliper/pads/disc...if u have no access to a machine shop there, use automotive valve shims of various thicknesses...as with any metal frame tho, don't have any gap between the swinger and the spacer, as it will put the swinger under stress...

 

[Ironman19t]

Ill check out the video it's just my piston sucks back in after I release the pedal and it should stay out to adjust to disc

thanx for the replys

 

[DGA]

Ill check out the video it's just my piston sucks back in after I release the pedal and it should stay out to adjust to disc

thanx for the replys

Pedal pressure down, open bleeder, close bleeder, pedal release, repeat.