|
|
Post by dejavu165 on Jan 18, 2020 15:17:31 GMT -5
Bought a gy6 scoot with rear disc brakes. The fluid was basically gone so I thought I'd replace it with new clean Dot 3. I also replaced the master cylinder because it was beyond dirty. The problem I am having is getting the system to pressurize. I pump out all the air and squeeze down the handle, tighten the bleed screw, and its feels like theres some pressure. But if I wait a min or 2 and squeeze again it goes straight to the handlebar with now resistance. I use a little hose on the bleed screw to make sure it well above the caliper and there is a steady flow of fluid before I tighten the screw. What am I missing here? This isn't the first time this has happened to me with these rear brakes. Last time I had to take it a mechanic.. The banjo bolts are clean and tight. There must be air in the system somewhere right? No leaks that I can see in the hose. One thing about that rear caliper I noticed is that when its bolted on, the bleed screw sits pretty low, which tells me it is below a lot of the fluid in the caliper. So I also take that off and set it up to its the high point. Any suggestions? Should I invest in a pressure bleed kit thing?
|
|
|
|
Post by aeroxbud on Jan 18, 2020 17:44:45 GMT -5
Was the lever ok before you tried bleeding it?
You could try tying the lever back over night. This might let the air work it's way up.
Might be a better idea to try reverse bleeding the system. Putting the fluid in from the caliper side. This should allow the air to move up, and out.
|
|
|
|
Post by 90GTVert on Jan 19, 2020 0:19:55 GMT -5
I would try what Paul said. Make sure the fluid level is good and pump up the brake then use a bungee strap or zip tie or something to hold the lever. Let it sit that way at least overnight. Then release the brake and see how it feels. Sometimes this practically works miracles.
|
|
|
|
Post by dejavu165 on Jan 19, 2020 17:01:45 GMT -5
Ok. I've got the handle ziptied down. I'll check it tomorrow. Im not sure what youre talking about when you say try adding fluid to the caliper side and reverse bleed the system. How do you suck it up to the master?
|
|
|
|
Post by aeroxbud on Jan 19, 2020 19:38:20 GMT -5
A bit like this.
|
|
|
|
Post by SMALL CC TEK on Jan 20, 2020 18:47:34 GMT -5
What they all said ! lol You have air fluid air fluid gaps , Fill reservoir Zip Tie lever to bar leave it for a few hours . When you cut the zip tie keep the lever depressed and slowly let it out and see if it starts pumping up hard . All that was doing was making sure all the air gaps went away by keeping the lever pulled at the master cylinder . You have a 5050 chance it works the first few pulls and bleed . Sometimes it is just easier to just reverse bleed on stubborn bikes saves holes in walls etc !
|
|
|
|
Post by 2stroked on Jan 21, 2020 18:02:07 GMT -5
You said u have a hose on the bleed nipple, is the other end if the hose submerged in clean brake fluid? It should be, it will keep the system from sucking air back in. Put the hose in the nipple, stick the other end in a bottle or jar of clean fluid, pump the handle 5-10 times, hold it tight against the bars, or use a clamp, then crack the bleeder sxrew back, when air stops bubbling out, tighten it back. Repeat. Repeat. Repeat. Then do he handle held overnight trick.
|
|
