Complete brake failure

Do you know anything about Range Rovers?

Actually if I were you I would seriously check out the front brake with urgency. The back brake is combined with only two pistons of the front brake. The front brake lever activates the other pistons and I consider this as not only the front brake, but also the fail safe. While you are urgently checking the front brake save time and money and band aids and get the back ones sorted as well.

I reckon the piston seals are gone and letting fluid bypass in the master cyl. If it were the other end there would be leakage around the pistons in the calipers


BTW Rangies have a similiar system and I found out the hard way. The "front" had failed at some time previously and the rear /front combo had a hose breakage. Right in front of my driveway... just after descending a very steep dirt grade 5 mins earlier.

Swinger wrote:

Never had this problem before: complete brake failure on the SW 600. Model is FJS600D3. Belting off the motorway at 80-90mph down a slip road to a junction. Pulled both levers - nothing. Imagine the feeling of nothing as the levers flop in your hands.

I do not recall anyone having this scenario before.

The brake fluid may have been compromised as you mentioned. Here is an interesting read ( http://www.aa1car.com/library/bfluid.htm ). When I replaced my brake fluid, I used a synthetic blend to provide higher temperature resistance.

Were the reservoir window low on fluid??

Without knowing maint, history of bike, hard to look for corrective measures.

If you lost lever(pedal in car) why didn't you try to pump up pressure while you were still in motion?

I would as min. change brake fluid/pull caliphers apart/ if rubber brake lines are soft, replace.

I think changing fluid every two years is recommend, I notice on my Concours, fluid looked dirty after only year.

I bike is brand new, Contact HONDA.

x

I am rider not somebody who gets on model numbers. I assume SilverWing scooter---- he mentions both brake levers=scooter to me, assuming they are hand levers.

There have been other silverwings, but they had mech, rear brake.



What should have been used if this is scooter, the cable operated parking brake, which at least would brought speed down.


John Grinsel

I always thought that the front and rear brakes did not share any hydraulics. The left lever activates the rear brake and the center caliper on the front brake, and the right lever activates the two outer calipers on the front brake. Referring to the service manual, it specifies two separate bleed valves on the front caliper - the upper bleed valve is for the front lever, and the lower bleed valve is for the rear lever. Why would both brakes fail at the same time?

I tried a little detective work, but could not tell if this is an ABS model. Would ABS cause your brakes to fail? I would think they would still work as normal, just have the possibility of locking up (if the ABS were to fail).

Now I do have to say, the poster must has solid brass balls. If both of my brakes were to fail, I would not pump them up and go about my way. It would get towed to the shop, and I would catch a ride home. Anyhow, glad that you came out of it safe and sound. Did you ever find out what went wrong?

Thanks for good advice folks. It appears it has nothing to do with the CBS. I’ll change the hoses for braided ones as well as the fluid both front and back. Reckon hoses and fluid have gone off. Unusual to happen to both at the same time but could be explained away by the fact the scoot wasn’t built for fast riding.

For the record, it doesn’t have ABS and is the FJS scoot rather than the GL. I always check the fluid levels before setting off. Yes I did try pumping (for dear life) when I had no braking. No I didn’t try reaching for the parking brake (it crossed my mind along with the my childhood years, what I really should have done with my life and places I would have loved to see before I died). No, I don’t have brass balls, just years of experience on every type of bike. I would advise not reaching for the parking brake whilst moving, that will:

destabilise the bike as you move your weight forward and to the right

you’ll have to take your eyes off the road and that will cause you to pull to the right (try closing your eyes briefly while moving and you’ll see what I mean)

you could be do something else with the hand that you use, like pumping the brake and steering

Cheers, Swinger

buddy19520 wrote:

I always thought that the front and rear brakes did not share any hydraulics. The left lever activates the rear brake and the center caliper on the front brake, and the right lever activates the two outer calipers on the front brake. Referring to the service manual, it specifies two separate bleed valves on the front caliper - the upper bleed valve is for the front lever, and the lower bleed valve is for the rear lever. Why would both brakes fail at the same time?

If something happened to make at least one of the front pistons overheat (caliper seized, contaminated fluid, whatever), then that could heat the others (even without shared hydraulics) to the point where the entire front was overheated, and then both levers would go soft.

buddy19520 wrote:

Now I do have to say, the poster must has solid brass balls.

Yes, agreed. Very big ones, too

Swinger wrote:

I would advise not reaching for the parking brake whilst moving, that will:

destabilise the bike as you move your weight forward and to the right

you’ll have to take your eyes off the road and that will cause you to pull to the right (try closing your eyes briefly while moving and you’ll see what I mean)

you could be do something else with the hand that you use, like pumping the brake and steering

And since the lever locks in position until you pull it the second time, if you were distracted by something and couldn't give it the unlocking pull, then the rear wheel could potentially lock up once the bike slowed down a little more.

Overheated brakes normally won't cause a loss of braking. There are two ports between the reservoir and master cylinder bores in most all Honda master cylinders and hydraulic clutch masters. If the caliper gets overheated causing the hydraulic fluid to expand the pressure can escape back to the master reservoir through the smaller port which is ahead of the master cylinder piston toward the output end of the cylinder. If the port gets plugged by sludgy brake fluid, you can get a locked up brake from overheating or dragging brakes. That's one of the most important reasons to change brake fluid every couple years or sooner if you live in a damp environment. Plugged small ports have been found on many older Goldwings that had neglected maintenance. Besides possible locking brakes plugged ports make it nearly impossible to completely bleed the brake system.
One possible cause of Swinger's excitement could have been due to a warped brake disk or something that pushed the brake pads away from the rotor. If you change brake pads normally one pushes the pistons back into the caliper cylinders. If you just ride off after reassembling the calipers and pads onto the bike there will be no brakes when you need to stop. It's critical with disk brakes to pump the pads up against the rotor after maintenance. It usually takes a few strokes of the master cylinder connected to the concerned caliper. I don't know what could have pushed the pistons back in Swinger's bike but that's about the only thing that could cause a complete loss of brakes which returned after pumping the levers. If the fluid level was normal in the reservoirs after this happened it could only be something that forced the pads away from the rotor. Perhaps vibration at high speed. The calipers are free to move from side to side in a floating mount so perhaps there was some vibration at the wheels, enough to work the pads back away from the wheel in the sustained high speed run.
I've ridden my SW up to nearly it's top speed (about 107 via GPS) but not for extended runs so I can't say what would happen on a longer run.

That’s a very interesting theory and I think you’ve cracked it. I wonder if it has something to do with the smaller wheels than normal bikes. A possible flaw in the design of super scoots?? I reckon that is why there is a special Swing tyre.



I’ve noticed a high speed wobble at the front but not made the connection until now. A high speed wobble from the smaller front tyre struggling for grip is nothing to worry about if you feel in control. I’m going to check that there is no play in the front wheel but I reckon the front tyre is not the special Swing one. I recently changed the back tyre for the recommend one but thought nothing of it – it wasn’t any more expensive so it was a simple choice.



So, lesson learned No2: anyone who rides hard and fast should stick with the recommended Swing tyres, the Bridgestone Hoop B02 (rear) and B03 (front) in the UK. They are no more expensive.



Swing

A digression:
Mine came shod with IRC tyres.
I've never heard of them before but they are Japanese - a company who have been making tyres for 80 years.
They seem to do the job OK.

Just to close this discussion off. Front tyre is a brand I've never heard of before. The previous owner - owned since new - was a paparazzi photographer in Paris. He freely admits he bought it for cheapness and around town.

Have dropped the speed on fast sweeping bends. Now 85 instead of 90mph. Reduced wobble and have brakes when needed. The failure has only happened the once.

Have discussed with Police riders who I train with and they suggest change the tyre for the recommended one. The problem with the Pan and Police spec bikes which used a non-recommended tyre came-up in discussion.

So, hope this discussion has added to knowledge of the forum and forewarned is forearmed.

S.