Bleeding rear brakes?

[Mudflaps]

So I've got a rg250 framed bucket racer (had it for 3 days now) and I need to bleed them up. I'm pretty sure I have it set up right, but can't get any pressure in them. I can bleed front brakes fine, but am now wondering if rears are different?

Can anyone point me to a good thread or give me some advice?

Cheers

[quickbuck]

If you have drained your fluid completely, then you will need to pump them for ages to get all the air out.....
The piston on the Master cylinder isn't very big at all....

One trick I have seen is to fill a CLEAN oil can with Brake fluid, and then put a plastic hose on it, and connect it to the bleed nipple. Crack the nipple, and pump the oil can.
Then you fill up the caliper, and the hose all the way to the master cylinder.

This gives you a very good head start.
Then bleed the remaining few bubbles out as normal....
Tap the caliper with a rubber hammer too, as there may well be some bubbles "stuck" to the walls.

Hope this helps you.

Remember cleanliness is next to godliness when it comes to brake systems... And the fluid will most likely take the paint off your oil can.

[Mudflaps]

Thanks!! I'll be out there tonight having another crack at them.

[Katman]

Have you bled the master cylinder before trying to bleed them at the caliper?

[Mudflaps]

Have you bled the master cylinder before trying to bleed them at the caliper?

um...no? How does that work?

[crazyhorse]

Use a plaster - not a good idea to bleed at all :rofl:

[k1w160]

I had exactly the same problem with my rear brake and spent several hours trying to bleed it.

Take the caliper off it's mounting but DON'T disconnect the brake hose.

Cable tie the caliper to somewhere above the master cylinder and proceed to bleed in the normal manner, any trapped air bubbles will rise and should bleed out fairly quickly.

It's a bit fiddly, but it works.

Cheers

[FJRider]

Use a plaster - not a good idea to bleed at all :rofl:

Hey ... I'm the smarty-pants ... :innocent:

[crazyhorse]

Hey ... I'm the smarty-pants ... :innocent:

Well, move over, there's room for the both of us :rofl:

[FJRider]

So I've got a rg250 framed bucket racer (had it for 3 days now) and I need to bleed them up. I'm pretty sure I have it set up right, but can't get any pressure in them. I can bleed front brakes fine, but am now wondering if rears are different?

Can anyone point me to a good thread or give me some advice?

Cheers

They are two different systems ... I have known a guy (NO NOT ME) that tried to bleed the BACK brake by pumping the FRONT brake handle ... (it didn't work)

[FJRider]

Well, move over, there's room for the both of us :rofl:

HB girls ... :no:

[Mudflaps]

I had exactly the same problem with my rear brake and spent several hours trying to bleed it.

Take the caliper off it's mounting but DON'T disconnect the brake hose.

Cable tie the caliper to somewhere above the master cylinder and proceed to bleed in the normal manner, any trapped air bubbles will rise and should bleed out fairly quickly.

It's a bit fiddly, but it works.

Cheers

Hey thanks. I'll give that a go. I was actually taking the caliper off last night(to try something similar to what you suggested) but stopped after skinning my knuckles trying to undo the bolts. Tomorrow maybe.

[Max Preload]

um...no? How does that work?

You take the banjo & bolt off and cap the threaded hole with your finger and slowly pump the lever until there's pressure, then quickly reattach the banjo with the bolt - easier if the M/C isn't orientated in such a way that brake fluid can't run out the hole before you reconnect.

Avoid the brake fluid getting on painted surfaces but if it does just rinse off with lots of water.

[Mudflaps]

You take the banjo & bolt off and cap the threaded hole with your finger and slowly pump the lever until there's pressure, then quickly reattach the banjo with the bolt - easier if the M/C isn't orientated in such a way that brake fluid can't run out the hole before you reconnect.

Avoid the brake fluid getting on painted surfaces but if it does just rinse off with lots of water.

Thanks for this.

It's now on the Saturday list of bike chores. I'll post how I get on.

Also on the list of chores is making new front caliper mounts so my new rim (read disk) fits. I'll post some pics of what I'm up to, maybe someone will know of a disk that will do the job instead of shifting the calipers.

[Mudflaps]

So just incase people were losing sleep over my brakes, I'm happy to announce that I fixed them!! I'm quietly (or not so as the case maybe) proud of myself. Thanks to those who gave advice.

I ended up pulling the whole set up apart and checking it piece by piece as I've only just bought it, so the problem could have been anywhere. I rplace the hose between the reservior and the M/C, Checked the M/C still actually pumped anything, and then re assembled. I took the caliper off it's mount, and hung it straight below the M/C. I took the bleed nipple right off, as Max Preload suggested (pretty sure that has to be the easist way I've ever bleed brakes!) and used my finger to block the hole on the down stroke of the brake lever. Then released my finger off the hole which is so much easier than trying to turn a ring spanner. Once I got fluid through the rest was easy.

Thanks again!!

Till the next problem....

[Jonno.]

Okay I'm in a similar situ, I've taken the fluid out of brakes and disassembled, put back together and I can't get fluid into the hoses no matter what I've tried. I've done a bazillion searches to no avail.
I've tried bleeding the master cylinder (I got a firm lever and fluid in the bore, put the banjo back on and nothing. Tried to then "bleed from the bottom of the hose, and from the caliper but got nowhere. Help me before I cut my ears off.

[Max Preload]

Okay I'm in a similar situ, I've taken the fluid out of brakes and disassembled, put back together and I can't get fluid into the hoses no matter what I've tried. I've done a bazillion searches to no avail.
I've tried bleeding the master cylinder (I got a firm lever and fluid in the bore, put the banjo back on and nothing. Tried to then "bleed from the bottom of the hose, and from the caliper but got nowhere. Help me before I cut my ears off.

Once you've bled the MC & reattached the hose, slowly draw the lever in. Close the bleed nipple. Let the lever out slowly. Leave the nipple closed then slowly pull the lever in. Then crack the bleed nipple and reclose. Repeat.

[Jonno.]

When I do that it seems to just suck the air back in when I open the nipple?

[Max Preload]

When I do that it seems to just suck the air back in when I open the nipple?

It expels the air. That's why you crack the nipple with the lever against the bar then close it again before releasing the lever.

You may also find it easier if you push the caliper pistons back to their limit and hold them there with a block.

[Jonno.]

The reservoir fluid should be going down right?
It's like it's creating a vacuum between the master cylinder and the caliper and no fluid is being pulled through.

[Mudflaps]

It expels the air. That's why you crack the nipple with the lever against the bar then close it again before releasing the lever.

You may also find it easier if you push the caliper pistons back to their limit and hold them there with a block.

Yeah I had very simular things happening, but seemed to go fine one I pushed the pistons right back.

[Jonno.]

Okay, I did it. I have firm brakes. Thank you all. I'm still not quite sure what it was I did but thank you :sunny::sunny::sunny::sunny::sunny::sunny:

[Mudflaps]

Okay, I did it. I have firm brakes. Thank you all. I'm still not quite sure what it was I did but thank you :sunny::sunny::sunny::sunny::sunny::sunny:

Such a good feeling eh!! I was stoked when I fixed mine. Nice work bro.

[Mudflaps]

Okay, I did it. I have firm brakes. Thank you all. I'm still not quite sure what it was I did but thank you :sunny::sunny::sunny::sunny::sunny::sunny:

Such a good feeling eh!! I was stoked when I fixed mine. Nice work bro.