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bleeding front brakes

PostPosted: Mon Jun 14, 2010 12:40 pm
by DevonCbx
A couple of years ago, I bled my back brake. I seemed to have no problem. Now I need to bleed my front brakes. I had read that this should be done with someone with more knowlege due to having 2 disc brakes to bleed. Is there a certain procedure to this? I would like to attempt this myself.

Thanks :?:

Re: bleeding front brakes

PostPosted: Mon Jun 14, 2010 1:55 pm
by zxbob
Here is two things I have done in the past that have worked fine. (without purchasing a mightyvac)

Remove the cap at the master cylinder to watch the fluid level. (refill as needed)
Loosen both bleeder valves on both calipers and let gravity do its thing. (use something to catch dripping fluid)

If you need to "push fluid" thru the system, start at the caliper furthest away from the master cylinder. (left side)
I have done this solo if you sit infront of the bike so you can reach the brake lever and the bleeder valve.
Put a small rubber hose on the bleeder valve to take the brake fluid into a container (16oz coke bottle works great)
With slight presure on the brake lever with one hand loosen the bleeder with the other hand, squeezing the lever
slowly just short of all the way to the bar, snug the bleeder valve at the caliper, release the lever and repete untill
you get clean fluid. (allways keeping an eye on the fluid level in the master.)

Follow the same for the right side.

I have never used the "speed bleeder" valves . . . . but I hear they work, maybe another option to explore.

Bob

Re: bleeding front brakes

PostPosted: Mon Jun 14, 2010 5:35 pm
by DevonCbx
Wow! What great information. Thanks for the quick rersponse :!: :!:

Re: bleeding front brakes

PostPosted: Mon Jun 14, 2010 8:00 pm
by EMS
I bled the brakes on my first car when I was 18 and that had four disc brakes :roll: I don't know who said you should leave this to someone with more experience, but if you bled your rear brake, you can bleed the front. Just do as Bob said 8) and start with the left, which is the furthest away from the MC. You should always bleed the longest line first. The front on the CBX can be a little tricky as air likes to be trapped in the 1 to 2 manifold on the lower fork bridge, but that should not scare you. people have used all kind of ingeniuos methods, like attaching vibrating devices to the barke lines to get the air out.
Go and attack it, we are here with advice if needed!

Re: bleeding front brakes

PostPosted: Thu Jun 17, 2010 8:17 pm
by Will
[quote="EMS"]I bled the brakes on my first car when I was 18 and that had four disc brakes :roll:

You are that young? My first car had mechanical brakes <grin>. My first car with 4 discs was 1968. It was a European car. Needless to say, American cars didn't have 4 wheel discs until 20 or 30 years later, at least.

Re: bleeding front brakes

PostPosted: Fri Jun 18, 2010 7:20 am
by EMS
Will wrote: You are that young? My first car had mechanical brakes <grin>. My first car with 4 discs was 1968. It was a European car. Needless to say, American cars didn't have 4 wheel discs until 20 or 30 years later, at least.


No, I am not, Will 8) The car was a Fiat 1500S Cabriolet with an OSCA engine. It had 4 disc brakes in 1961. :shock: Ahead of its time.

Re: bleeding front brakes

PostPosted: Mon Jun 21, 2010 11:11 pm
by Will
Coincidence or what? My first car with disc brakes was a '60s Fiat. It was a 1968 Fiat 124 Sports Coupe. And yes, it had 4 wheel discs when Americans were still sticking out their foot to stop. It was a great car, unfortunately the metallurgy was still pre-war. That car had engineering stuff that was unbelievable.

For instance, pollution control was in it's infancy. One of the first steps in the government procedure was "Open the hood." So, there was a switch at the rear of the hood. It raised the idle and I don't know what else, but when that hood was up, it was legal <grin>.

Re: bleeding front brakes

PostPosted: Wed Jul 21, 2010 7:22 am
by Samelak
I just rebuilt my front master cylinder and calipers after powdercoat. I bled the system, but it seems like I have to pump the lever several times to get a good feel. I get a steady stream of fluid (no bubbles) from the bleeder screws. Also, the brake lever slowly pulls all the way back to the handlebar with constant pressure. I really don't want to pull apart the master cylinder again, but is it possible that it may be bleeding past the seals or trapped air somewhere. I have no leaking fluid from the cyclinder or calipers.

Re: bleeding front brakes

PostPosted: Wed Jul 21, 2010 11:16 am
by NobleHops
Samelak wrote:I just rebuilt my front master cylinder and calipers after powdercoat. I bled the system, but it seems like I have to pump the lever several times to get a good feel. I get a steady stream of fluid (no bubbles) from the bleeder screws. Also, the brake lever slowly pulls all the way back to the handlebar with constant pressure. I really don't want to pull apart the master cylinder again, but is it possible that it may be bleeding past the seals or trapped air somewhere. I have no leaking fluid from the cyclinder or calipers.


I thrashed and thrashed with this. There is a splitter that is a pain to clear, and also the banjo at the MC can trap air. I did everything under the sun to get mine bled, here's a few pieces of advice I got in no particular order:

1: Gravity. Remove calipers, remove right headlight bolt, remove splitter, hang calipers from the ceiling with a shim between the pads. Tap and jostle system to dislodge air, leave overnight, bleed in this position the next day.

2: If you try to bleed in place, remove the lower caliper bolt, loosen the upper, and rotate the caliper till the bleeder is at 12:00. Bleed the left side first, then the right.

3: Bleed the MC Banjo like so: pump up the system, squeeze brake lever and WHILE YOU SQUEEZE crack open the banjo and let some fluid pass the sealing washers. Tighten WHILE STILL SQUEEZING. It will be helpful to have a friend with a wad of paper towels cradling the banjo while you do this.

4: After verifying that the smaller of the two holes in the MC between the reservoir and cylinder is indeed clear, pull the lever back far enough (2/3?) and hold it there with a strap such that these holes are aligned with those beneath. Close the reservoir back up, tap and jostle the lines as best you can to dislodge bubbles, and leave it like that for a day or two. Do this on the sidestand with the bars at full left lock such that the reservoir is as high as possible

5: Sacrifice a goat

Good luck!

N.

P.S. In the end I had to have my MC re-sleeved, it would not seal after the chemical stripping done when it was powdered, or perhaps just because it was old. Also, my powdercoater was careless and I had to go after all sealing surfaces with a dremel so that they were perfectly clean and free of powder, including the neck of the MC. There is a thread somewhere with my thrashings detailed.

P.P.S. I also converted to a two-line setup and removed the splitter altogether.

Re: bleeding front brakes

PostPosted: Thu Aug 12, 2010 8:01 pm
by strider784
I have speedbleeders on my '96 ST1100, they work great. Annual maintenance at least once a year, completely changing brake fluid in a few minutes. You can stand at the handlebar and gently pump the brake lever unitl the brake fluid runs clear. Do each disk separately. I have SB on the rear brake and clutch also, makes short work of it. There should be a cross reference at the SB web page.
Ben,
St. Francis, MN

Re: bleeding front brakes

PostPosted: Tue Dec 28, 2010 8:25 pm
by ajs350
I tried all of the techniques Nils mentioned above on my 80 to no avail. No matter what I did I still had a spongy lever that would pull all the way back to the bar.
I spoke to Bill at TIMS and shared my problem and that these were probably the original brake lines. A quick check of the markings on the lines and he confirmed they were the originals and suggested new lines as even his team never seemed to get original lines to work well.
I received the 3 braided lines and covered them with 5/8 shrink tubing to give that original look. Put them on today and had them bled in an hour with a hard lever that won't even come close to the bar. What a difference! So for those who read this later and who have old rubber brake lines just pitch them and get a good set of new ones.
Ross

Re: bleeding front brakes

PostPosted: Tue Dec 28, 2010 8:33 pm
by NobleHops
ajs350 wrote:I tried all of the techniques Nils mentioned above on my 80 to no avail. No matter what I did I still had a spongy lever that would pull all the way back to the bar.
I spoke to Bill at TIMS and shared my problem and that these were probably the original brake lines. A quick check of the markings on the lines and he confirmed they were the originals and suggested new lines as even his team never seemed to get original lines to work well.
I received the 3 braided lines and covered them with 5/8 shrink tubing to give that original look. Put them on today and had them bled in an hour with a hard lever that won't even come close to the bar. What a difference! So for those who read this later and who have old rubber brake lines just pitch them and get a good set of new ones.
Ross


Crap, sorry none of that worked for you. Not as sorry as the goat though ;-).

N.

Re: bleeding front brakes

PostPosted: Tue Dec 28, 2010 8:54 pm
by oilheadron
"American cars didn't have 4 wheel discs until 20 or 30 years later, at least."

You ARE kidding, right???? :)

Re: bleeding front brakes

PostPosted: Tue Dec 28, 2010 9:10 pm
by Don
Will wrote:My first car with 4 discs was 1968. It was a European car. Needless to say, American cars didn't have 4 wheel discs until 20 or 30 years later, at least.
Yeah, pretty sure he was kidding

The '65 Corvette had factory 4 wheel discs and I'm pretty sure it was made in America . . . . . :wink:

Don

Re: bleeding front brakes

PostPosted: Tue Dec 28, 2010 10:04 pm
by Will
Don wrote:
Will wrote:My first car with 4 discs was 1968. It was a European car. Needless to say, American cars didn't have 4 wheel discs until 20 or 30 years later, at least.
Yeah, pretty sure he was kidding

The '65 Corvette had factory 4 wheel discs and I'm pretty sure it was made in America . . . . . :wink:

Don



No I wasn't kidding. I should have said "regular" American cars didn't have 4 wheel disks. Now, even my pickup truck has 4 wheels disks.

I wasn't aware of that Corvette started with 4 wheel disks in '65. Corvettes were out of my price range. My 68 Fiat was not a sports car or exotic. It was a normal driver, to me. My 90 Taurus SHO had 4 wheel disks, but the normal Taurus had drum rears.