Bleeding brakes

Hi Chav' we need some more background, like did the brakes ever work, have you cleaned / overhauled the master cylinder / calliper pistons, brake lines?

I had a lot of the Wiltshire bikers working for me when I converted the old Roundways loony bin in Devizes.

Good luck with your brakes, if it is any comfort, I have stopped bleading the brakes on my project Kawa' as they are still spongey, I thought I would let them settle for a week or 2. Wiz.

 

Been there done that.
http://www.xjbikes.com/Forums/viewtopic/t=15859.html

 

When I got the bike, the brakes were seized on. I drained the system ( pumping worked ) and found that the pistons were in a very bad way. I replaced the pistons with stainless ones, and also the pads and all the copper washers.
Now I have the problem !

 

Sorry to resurrect this thread. Or also for not starting my own. But I got a new MC and new lines. I bled my brake the usual way, got all the air bubbles out (or so I think) and i keep filling the MC (never let it run dry) but the brakes do not build pressure. I am bleeding all 4 bleeders. I am not getting any more air out of either four bleeders (I have anti dive system) Am I supposed to, or is it absolutly neccesary to fill the MC and then "CLOSE" the MC after you get the air bubbles out, in order for the system to build pressure? Because I have been doing it with the cap off the whole time. (never letting it run dry of course) Please help.

 

How come you have 4 bleed valves?

 

I have the anti dive system. They are below the calipers. The instructions says to bleed those first. and then the calipers. They are integrated.

 

Try bleeding the banjo bolts...

Technique is the same as bleeding the bleeders ie. pump the lever until you get some pressure, then ease the banjo bolt slightly. A hiss or bubbles will come out (keep the lever back to the bar, do not release). Tighten the banjo bolt up and repeat for all the banjo bolts (even the one on the MC). If you can't get pressure to build up, bleed the MC banjo bolt first until no bubbles come out and move along the line to the banjo furthest from the MC. Good luck and keep a lot of water on standby as a lot of brake fluid will spill from the banjos. Also use eye protection as the banjos can squirt you good. I use a squirt gun and wrap the banjo I'm bleeding with a rag. Just listen for the bubbles escaping...

After you get good pressure, bleed the bleeders.

 

Thanks classic racing. But, I am getting decent quirts coming from the bleed valves. I will nevertheless try the banjo bolts as well. My main question above was:
Is it necesary to keep the master cyl. cap close while bleeding the brakes? or can I do it with the cap off?

 

I usually set the cap back on to prevent geysers. You don't have to have it screwed on, just don't get violent with the lever.

 

Yup, bigfitz is right. I forgot that one. No need to screw it on, just leave it loose

 

I tried Classicracing's advice and it released the remainder air in the system. Finally build up pressure. Thanks fellas.

 

Just did a complete brake job on my bike this afternoon. Knew I needed to flush out the 27 year old fluid so I went ahead and bought a Mity-vac. I am thoroughly impressed with how easy it made the job.

I highly recommend one or at least find a buddy who has one

 

Yep, after I finished the job my buddy 's friend told me he had one and it makes the job soooo much easier. I'm going to look into buying one in the near future.

 

I picked mine up last week at Autozone for $30. It actually came with a vaccum gauge and has several different uses.

 

I have a Miti-vac, and I also picked up
http://www.harborfreight.com/cpi/ctaf/d ... mber=92474
on sale one day for maybe 10 or 12 bucks. but at $20, it is a fine deal.

I really need to fix a canning jar lid with hose barbs so I can have the larger container rather than the tiny cup that the vacuum pumps come with.

 

The Miti-Vac is great. It really makes bleeding brakes pretty quick work. I think the biggest benefit was that I didn't have to worry about erroneously spraying brake fluid all over the place.

 

One note of caution on using the Mity-Vac for brake bleeding: It can work TOO good and fool you.

I kept getting a nice STRONG stream of bubbles. And kept getting it. And kept getting it. Lots of nice fat bubbles. After nearly a pint of fresh fluid through the system. More bubbles. WTF???

The Mity-Vac was drawing air IN around the bleed screw threads and then INTO the bleeder through the bleed hole so it APPEARED I was still getting bubbles from the system. A couple of turns of teflon tape on the bleed screw (be careful not to block the hole, threads ONLY) and my mystery solved itself. (Thanks to a suggestion in the Mity-Vac manual who reads those?)

 

if you have better things to do with your 20 or 30 bucks, just get a wide mouth water bottle, two lengths of hose, drill appropriate holes in the lid, and suck
when your done pull out the hose, put a piece of plastic over the bottle, screw on the lid and toss it in the garbage

 

Polock
not in the garbage. Take in to recycle it.

 

Fitz, had the same problem. Never could seem to get the bubbles out but after nearly a pint I knew I must have. I would add and this come from experience that you really need to keep an eye on the level in your master cyclinder I was bleeding away down below when I thought my kid was standing over the bike sucking on a straw in an empty can. "Do over"