How much fluid pressure should I have at the master?

[rkstew]

It's actin funky like it has no pressure while I'm bleedin the brakes, ( All FFFFFFF) day lol

When I squeez the perch it does nada, barely drips out>>>

[matts27]

Sounds full of air, use a mighty-vac and pump fluid in from the caliper bleeder to fill the system.... or you can vacumn suck the fluid to the caliper by using the other fitting on the mighty-vac. When done, I still use the pump method of squezzing the lever to get the solid feel in the brakes. Matt

[Zakradu398]

To bleed my brakes. I fill up the resi, and connect a small tube to the bleeder screw and fill that tube up with fluid and keep pumping till it gets tough. the bubbles will come through the tube and the fluid will go in from both ends :)

[CJM]

About the only way I ever can get them to bleed is to use a brake pump/vac. The master is just to dang small or something and doesnt push enough air out.

[rkstew]

this is what I'm gettin at. At the Master itself I have not even enough pressure for it to drip out FFS

we're talkin 2-3 lbs max. I know fluid dynamics and I think I have a bad rezzy.

it should at least shoot out over a foot at the master right?

[CJM]

Should an actually happening are 2 different things. Like I said, I cant ever get them bled good unless I use the brake vac at the caliper.

[rkstew]

Originally posted by CJM
Should an actually happening are 2 different things. Like I said, I cant ever get them bled good unless I use the brake vac at the caliper.

So that little of pressure is normal? I'm a dumb farm boy, but I am *** deep in a mechanical engineering degree:lol

I was just goin to reverse bleed them later because I'm so pissed off:lol

Have you noticed tis little of pressure off any of yours? My 250R was cake and these are braided steel lines here:confused:

[CJM]

Yes, Im not quite sure why but the dang things just dont have any pressure to push it seems. The back master bleeds just fine, dang front sucks.

[DnB_racing]

Originally posted by rkstew
So that little of pressure is normal? I'm a dumb farm boy, but I am *** deep in a mechanical engineering degree:lol

I was just goin to reverse bleed them later because I'm so pissed off:lol

Have you noticed tis little of pressure off any of yours? My 250R was cake and these are braided steel lines here:confused: it could need a master rebuild, if there is almost no pressure, it could help to get a rebuild kit,

try bleeding first but if your getting no results, then get the kit to rebuild

[rkstew]

I can get one barely used for 35 and rebuild kits are 25 :lmao

[rkstew]

Originally posted by CJM
Yes, Im not quite sure why but the dang things just dont have any pressure to push it seems. The back master bleeds just fine, dang front sucks.

Hydraulics is a very simple business and if I had the length of the piston plunger and the diameter, I could tell you real quick what pressure it multiplies.

Im just going to pick up a 450R master when I get those YZF calipers you clued me in on today.

Thanks again BTW, whole setup will cost me round 75 with 450 master, and yz calipers...

I know a guy lol

[DnB_racing]

Originally posted by rkstew
I can get one barely used for 35 and rebuild kits are 25 :lmao if you cant get any pressure from yours, then get a good used ...either way! or rebuild your old, I trust my work before ebay used, but they are both options to be considered



lol we posted the same time I was going to recomend the 450 master, instead of the ex

[rkstew]

I don't use e-gay, I'm 20 minutes from one of the largest recyclers for OHVs in the midwest, if not the country:)

I know them well, weve raced together since we were 10:devil:

[NacsMXer]

If you can find a big syringe (I got a bunch at a vet supply warehouse), you can reverse bleed the system from the calipers up and have a fully bled system in no time.

Just get a length of clear hose that will fit over the bleeder valve on the caliper and attach it to the syringe. Fill the syringe with clean brake fluid and attach to bleeder valve (remove air from syringe first). Start injecting fluid and you will notice that the air bubbles/fluid will start escaping through the master cylinder at the top of the system. Air wants to travel up, so you are bleeding the most efficient way possible.

This is how I did my brakes last time when I installed YFZ 450 dual piston calipers and 450R master cylinder on my 400EX. First time using reverse bleeding and it was the fastest most effective bleed i've done. Used to take 30 minutes or more using my Mityvac vacuum pump trying to suck the air out. Much easier to "push" the air out the top in the direction it wants to go.

[rkstew]

reverse bleeding them worked great but now I can't air out of he ressi:grr:

[NacsMXer]

May be an air bubble trapped in the banjo bolt going to the master. Hold the brake lever in, and gently crack the banjo bolt loose until a little fluid starts to leak out. Retighten the bolt, and then release the brake lever.