Bleeding brakes 250R - me idiot??

[Dirtcrasher]

Cleaned the whole system and rebuilt the caliper which won't last (another story) but when I reassembled everything I couldn't get them to bleed? I put the bleeder screw in a container of fluid, filled the resevoir and pumped and cracked, repeat etc etc but couldn't get it to work. It was totally dry so maybe there is still air in there? I even forced fluid in through the bleeder with a syringe but still nothing? If I leave the bleeder open fluid goes up and down as I move the pedal yet even upon tightening never seems to build up pressure?

So I tried my other master cylinder and nothing different there - Are they both cooked or am I an idiot? Thanks for any help!!!!!!!!!

[deathman53]

they can take awhile, I bled the brakes on my 200x last night and I pumped for atleast 40 minutes, same as on my trx250r and atc250r. there must have been alot of air in there. once you start seeing air bubles coming out of the master cylinder you are getting close.

[hrc200x]

Are you sure your bleeding them right, after you pump the peddle you hold the peddle down and then crack the bleeder (air or fluid should come out), tighten the bleeder, then pump the peddle, repeat. Make sure to keep the resivour full at all times. YOu could also take the line off the caliper and hold your thumb and index finger over the line end and see if you can feel pressure building up, if so that means your mastercyclinder is working, if not somting must be wrong.

[sandrooster]

Insure the master is functioning properly first.

Disassemble the master to insure there is no buildup of gunk. Then reassemble with new brake fluid. This will save alot of time bleeding out the air.
You can also take off the hose to clear and fill. Last, insure the caliper doesn't have debris inside the fluid channels.

['86X]

Open the bleeder (make sure it's not packed with mud or dirt). Fill the resirvore and leave the cap off. Walk away and come back in about 20 min. It should gravity bleed for the most part. Then if you want you can pump it and open the bleeder like the others said. All the air ion the master is not allowing it to build any pressure or to move any fluid. Let it gravity bleed for a while and this should help. If that doesn't work you can try a hand vacuum pump on the bleeder also.

[NOS_350X]

heres a little trick that most people dont know. on your bleader thing that you loosen take a carb overflow hose and put over it so air wont go back into it. like they said pump and pump, then hold down, open, close, and repeat. the hose stops air from going back into the brakes.

[Dirtcrasher]

How do I make sure that the master cylinder is actually working CORRECTLY??

The real scoop - this trike has sat indoors for appx 12 years. The fluid is almost gelified. The caliper was messed with so I cleaned it and rebuilt it. Looks to be fine, but I'd like a spare. The master and line I took apart and cleaned up with brake cleaner. There are no obvious tears or scored cylinder bore but I'm sure there is some wear. I put fresh fluid on all the cups during reinstallation but didn't fill the hose or caliper body or the master body.
You guys all know the situation - having spent over a grand and thinking "this will be the last order I have to place" and then something like this comes up again.
I'll try bleeding more today but I just want to make sure that the master is good.

[whiteman350x]

I have fought the same fight. I usually disconnect the line from the master and hold my finger over the hole. Pump several times and hold the lever down. Move finger. Repeat. This will show if master will pump. Takes a while to refill system. I bought a mity-vac. This really helps with bleeding a dry system.

[dune rider]

when i did my 84 250r atc i had use my shop vac to suck all the air out of the brake line. then i pumped for about 10min then they work fine :twisted:

[Dirtcrasher]

I GOT IT!!!!! Here's what I did, yelled, cursed, punched stuff and then walked away and calmed down. Then I took off the master AGAIN!!!!!! and filled the resevoir and inside where the hose goes - held it horizontal and set it down. Then I cracked the bleeder and forced fluid through the caliper with a syringe - up to the top of the brake hose and bent that hose over to the horizontally held master and attatched them together. Then I mounted everything up and it bled almost immediately.

I guess they just don't have enough of a stroke to get that air out of there quickly??
I throw calipers on my truck, open the bleeder - stuff it in a jar of fluid and slowly pump it and watch the bubbles disappear. I never need help and never have air but it's just a different system.


Thanks to all who replied!!!!!!! :-D :-D :-D