spongy front brake after multiple bleeds

Brakes were not great when I got the wing recently, so one of the first things I did was bleed the system. The linked side is now pretty good! A hard squeeze can now activate front ABS.

The front brake is still bad after multiple bleeds. The lever can pull to the bar without much effort, and with minimal braking effect. With constant pressure, the lever stays in place, so it doesn't seem like a master cylinder seal issue.

The bike is 13 years old, and I'm guessing has original brake lines. My hunch right now is that the front brake lines need replacing and are just really stretchy and unsafe at this point. Does this sound right? I see OEM lines are ~$100 for the two new pieces, and probably have been sitting on the shelf for years at this point. Any tips for (hopefully less expensive) new lines? Or other areas to troubleshoot?

It sounds more like air in the system if it's that spongy, unless the brake line is really, really knackered.
Have you done the usual stuff like holding the brake level back overnight?

Steve, you're probably right. The parts of the hoses that I can see appear to be in good shape without cracks or visibly aged rubber. I have tried the zip tied lever trick and also bleeding from the banjo at the master cylinder with no effect. It seems like the hose would be a vertical run with no upwards bends for air bubbles to collect, but maybe there is near the ABS system?

I'll try the zip tied lever trick again.

I overhauled my front brake caliper recently and it took quite a while to get it feeling right. My theory is that there was air trapped in the lower cylinder. Try giving the caliper a few sharp taps to see if it will dislodge any air.

If your brakes got to the point they where weak/spongy you probably need to take a closer look at your master and calipers(as in inspect/clean/overhaul) as there's probably some other issues, if your old fluid looked real bad is probably moisture saturated, this will damage seasl and usually cause corrosion on pistons. At a minimun, remove front caliper and clean exposed area of caliper pistons to insure they are not binding on seals, just move them out slightly by pullig lever slowly, clean with toothbrush and degreaser.

I did the zip tie lever trick overnight again. This time, I did a few lever pulls of bleeding from the banjos at the master cylinder, in case some air rose to the top of the system. They are now noticeably better.

There are a bunch of hypothesis around why the zip tied lever trick works, and I am not sure what ones are accurate. But I suspect that it may at least partially force some of the air into the brake fluid solution which would mean that it's a temporary fix unless you do a brake bleed right after. So, that's what I will do. I will try this lever trick again followed by a full bleed, possibly twice, and then follow up with my results.

Cheers!

I also have some good new pads on hand as well, so I may do as zrx212 suggested and do a lazy piston cleaning + inspection before driving the pistons in to install new pads.

silverwang wrote:

I did the zip tie lever trick overnight again. This time, I did a few lever pulls of bleeding from the banjos at the master cylinder, in case some air rose to the top of the system. They are now noticeably better. (Snip)

Bleeding from the master cylinder banjo? Good to hear that was somewhat successful. But can you please explain what you did. Crack open the banjo bolt while you squeezed the brake lever just as you would with a caliper bleeder valve?

Cosmic_Jumper wrote:

silverwang wrote:

I did the zip tie lever trick overnight again. This time, I did a few lever pulls of bleeding from the banjos at the master cylinder, in case some air rose to the top of the system. They are now noticeably better. (Snip)

Bleeding from the master cylinder banjo? Good to hear that was somewhat successful. But can you please explain what you did. Crack open the banjo bolt while you squeezed the brake lever just as you would with a caliper bleeder valve?

Yes, that's exactly what I mean for the master cylinder banjo bleed. During conventional bleeding, or vacuum bleeding that is not fast enough, you might get the fluid exchanged but air bubbles may remain floating at the top. That trick is supposed to help when there is air at the top of the system, near the master cylinder.

I think the zip tie lever trick forces some amount of air (bubbles at the top of the system or in the ABS module) into solution of the brake fluid, so I will also do that a couple more times followed by a full bleed (from the caliper bleeder) immediately after.

I'll report back on the results of that!

The zip tie trick usually works. The other thing I like to do when the brake pads are a bit low is to drive the pistons back in (having cleaned them first) fully, which pushes fluid back up to the master and helps to move air out.

Have you also checked that the sliding pins on the calipers are well-greased with silicone grease? If they are seized then brake force will be lost flexing the caliper.

I'm reading this topic on a spongy front brake that's been bled multiple times. It's piqued my interest simply because there's been no mention from the OP or anyone else offering advice asking which of the two bleed valves was opened first. Bleeding the upper front valve before the lower might be the problem.

The correct sequence is bleed the lower bleed valve, close it, then bleed the upper valve. I'm really not into tinkering, but when I changed the brake fluid on my Silver Wing, I bled front lower, front upper, then rear brake. When the job was completed I had no sponginess in the brakes whatsoever, I went for a ride afterwards and everything was fine.

Hi,
I've been following this topic with interest and have a related question.  I have a 2002 Silverwing (only 6,800 miles) and the brakes aren't "spongy" or anything.   I have noticed that, for the same amount of squeeze, the front brake has less stopping power than the rear brake.  Is this by design?  (For those of us who have thrown ourselves over the front-handlebars of our bicycles when we were 12...

Thanks,
Teragar

TeraGar wrote:

Hi,
I've been following this topic with interest and have a related question.  I have a 2002 Silverwing (only 6,800 miles) and the brakes aren't "spongy" or anything.   I have noticed that, for the same amount of squeeze, the front brake has less stopping power than the rear brake.  Is this by design?  (For those of us who have thrown ourselves over the front-handlebars of our bicycles when we were 12...

Thanks,
Teragar

Teragar, I'm surprised no one has answered your question.
The rear brake is linked to one piston on the front caliper so when applying the REAR BRAKE, the FRONT is getting some stopping power also. The FRONT BRAKE however is NOT linked to the rear hence less stopping power.

The answer is in your Owners Handbook on page 68. It explains the Silver Wing is equipped with a Combined Braking System, that's the CBS logo on your front mudguard/fender. Operating the front brake lever applies the front brake. Operating the rear brake lever applies the rear brake and a portion of the front brake. The front brake has an upper, middle, and lower cylinder and pistons, hence the upper and lower bleed valves.

Which is why I suggested the OP of this 'spongy front brake after multiple bleeds' may be bleeding the front brake upper and lower valves in the wrong order. That was four weeks ago and he hasn't posted an update since.

Being an optimist I'd say that was the problem.

There seems to be some confusion here on the way the brakes work on SW, no expert here but my research and 45+ years as a mechanic perhaps may help. My general observations.

1. The front brake lever only operates upper and lower pistons on front caliper, completely independent system, the upper bleed valve on front caliper is for that hydraulic system only. 
2. The rear brake lever operates rear caliper initially at partial lever applications(low pressure) and then center piston on front caliper at full lever (higher pressure) thru a delay valve, the center on front caliper and rear caliper bleeders are used for this system.
3. IMO the bleeding sequence only "Really" applies to the rear master, as no fluid is exchanged with front master and/or is system. IOW either front or rear brake levers are getting weak/spongy is an isolated issue to that system. 
4. In general the reasons for "spongy" lever have been discussed here, some not so common are, out of balance/vibrating wheel, a bent/warped front disk, bad wheel bearings, improperly installed/loose wheel, fork, caliper ??
5. BTW JIC correct bleed sequence, Front brake/upper bleed valve front caliper, Rear brake(ABS)/lower bleed valve front caliper 1st, then rear caliper bleeder(reversed for non ABS.)
6. Tip coating bleed valve threads with thick grease prevents drawing air thru threads.
7. BTW never seen a "CBS' sticker on a SW here. Pic rear master bleed.

zrx212 wrote:

BTW never seen a "CBS' sticker on a SW here.

So as well as the FSC Silver Wing not getting H.I.S.S. the Honda Ignition Security System and the 12v power socket in the left hand glovebox that the UK and Europe FJS Silver Wing has. Honda have also skimped on adding ABS & Combined Braking System in big letters to each side of the front mudguard.