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Brake issue on my Gen 5


DSA

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Hi Folks,

 

Ever since I got my 2000, I've been struggling with the brakes.

- Pulling the lever doesn't seem to generate as much stopping force as I'd expect.

- The Pedal was really bad when I got the bike - hard as rock, practically no travel or stopping force.

 

I rebuilt all three calipers, bled the system and swapped to brand new EBC HH pads all around. The pedal is now somewhat better, but still nowhere near where I'd expect to be. It can barely bring the bike to a stop - but it WILL prevent me from turning the rear wheel by hand with the bike on the center stand. The lever still isn't what I'd expect, either. 

 

One other potentially strange thing I noted: If I press the pedal, it starts out firm with not much travel. But if I leave the pedal pressed and then pull the lever, the pedal softens and sinks down. Doesn't seem to add any additional braking forces when it sinks down, though. 

 

-The back wheel spins freely with just a little drag, as one would expect. I don't think I have binding brakes or stuck pistons.

- I THINK I've bled the system properly. The lever actually feels great, nice and firm, but just doesn't generate as much stopping power as I'd expect. The rear...I followed the bleeding procedure as best as I could. I removed and tilted the front left caliper, and also relocated the rear caliper to the top of the disk (with the bleed screws at the highest point) when I bled them. Any insight on what could be going on here?

 

Thanks in advance.

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First I know nothing of the VFR brakes, but the ST1300, Goldwing and CBF1000  have similarly linked systems I'm familiar with.  By your description, when the pedal is hard at first, sounds like the front middle piston may not be moving the pads.... at least until you pull the lever, then you have all the pistons acting on the pads.....  they move, your pedal goes down.  You've rebuilt the calipers, so I'd think you paid attention to ensuring nothing is binding in the slides and pins, pistons are moving freely, pads are not binding (some aftermarket ones need a tweak with a file)...... I'd double check all that, kinda leaves the proportioning or metering valve..... but if you bled it successfully, maybe not.  I'd just recheck everything in detail and let us know how it goes.  I'll have to refresh my memory on how the SMC plays into the picture, I know on ST's if it acts up, the rear brake can have issues of not releasing.

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Thanks for the response. I took the calipers off and checked the action of the pistons and pins - everything seemed to be in order. But when pushing in the secondary master cylinder with the LF caliper off, I realized that I could push it in with no resistance. This seemed odd, and pointed the finger at either the SMC, or at something in between it and the rear caliper.

 

I went ahead and bled the PVC. Last time I did it, I removed the caliper, angled it and then used a vacuum pump. This time, after first using the vacuum pump, I also did it manually, having a friend actuate the SMC as though it were the lever or the pedal, while I bled the PVC. It worked wonders - the lever now generates all the force I would expect, and slows the bike down in a hurry. The rear is now much improved; the pedal isn't rock hard and actually moves a fair bit, but the braking force still isn't what I'd want. 

 

Next: I suspect the rear pads might be contaminated by the grease I apply to the back of them. It's a pain to get those rear pads in, and I dropped them/messed up several times and definitely got grease on them. I am going to switch out one of the front pair with the rears and see what that does. 

Additionally, I didn't fully bleed the pedal circuit this time, just the PVC. While that was probably the issue, I really should do the entire pedal circuit. 

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22 hours ago, DSA said:

Hi Folks,

 

Ever since I got my 2000, I've been struggling with the brakes.

- Pulling the lever doesn't seem to generate as much stopping force as I'd expect.

- The Pedal was really bad when I got the bike - hard as rock, practically no travel or stopping force.

 

I recently acquired a 98, and I've had EXACTLY the same thoughts about the brakes.

 

Lever stops the bike, but it's like trying to stop a freight train. Normal braking is fine, but it takes a surprising amount of pressure to incite "hard" braking. I suppose it's nice that it's not overly sensitive, but geez! I'm pulling so hard it's difficult to predict its limit. I'd rather have a shit ton of braking power with moderate pressure, and never have to resort to heavy lever pressure. Not very confidence inspiring as is.

 

Pedal is STIFF, nearly non-responsive. Practically have to tip toe on it to feel decent amount of braking force. Challenging to modulate. My last bike (1988 Honda Hawk GT) seemed to have overly sensitive rear brake: grabby with light pedal pressure. Took a lot of getting used to on that rear brake.

 

I have a set of EBCs, all 18 piston seals, boots and liter of brake fluid. Going to replace the front master cylinder as well. Hopefully, things will improve after the rebuild. I'm hoping I don't have to rebuild the rear MC, SMC or the PVC. Fingers crossed.

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Yeah, this definitely sounds very much like what my situation was.

This winds up being a process of elimination: Once pads and calipers are ruled out through replacement and rebuild respectively, you're left with the three master cylinders, the PVC, delay valve or the lines themselves. The hydraulic action of the master cylinders can be checked by pressing down on the pedal, lever or SMC and then opening a corresponding bleed screw. You'd expect the pedal/lever/SMC to sink down when that happens. 

After I'd done all this, I went after the PVC. I checked this by trying to manually actuate the SMC when the LF caliper was off the bike. Mine sunk in with no effort, which implied air in the system. I thought I'd bled it properly, but evidently not. Re-bleeding with a good-quality MityVac and hand-bleeding while a friend actuated the SMC really fixed up the lever for me.

The pedal is no longer rock hard, as I mentioned in my previous post, but I still have a couple of things to try there to really get it to where I want, including completing the bleeding process in the correct order, and rotating pads to check for contamination.

 

Good luck - it's just a matter of time and effort before you get to the bottom of is. 

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I would suggest going through the factory bleeding process (again?): https://www.vfrdiscussion.com/index.php?/files/file/171-98-01-honda-vfr-service-manual-optimized-bookmarked/

It sounds like something isn't right if your lever feel is that soft and/or brake performance is that weak. 

 

I flushed and rebuilt my brakes including all three master cylinders, installed braided lines and EBC HH pads, and my braking performance is great. Lever pull is short & linear, braking force available is far in excess of requirements, easy two finger braking is more than enough in most riding situations. Post brake overhaul I have even been running with my adjustable lever set at the second or third position (much closer to the bars) since I am able to exert maximum brake force well before the lever contacts the grips. I did install speed bleeders and also used a mity-vac during my refurb and bleeding, which may have helped me get positive results. 

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