I've a 98 model VFR 800 (FiW) and have recently discovered that the front tyre has worn badly. It turns out that the front brakes were binding. The bike has 50,000 miles on the clock and the disks and pads needed replacing. I've replaced disks, pads and seals with genuine parts but the front brakes still bind enough to get everything hot. The seal housings are not clean and the pistons move just fine, so I'm at a loss to explain this. Can anyone suggest something? I have seen an old posting that suggested that perhaps the brake lines need replacing. New lines is not a cheap fix and I'd like to know that the lines are the problem before going that way. thanks, Phil
I have worked on some older bikes with failing lines. Even when they looked ok from the outside, and I flushed ten gallons of new brake fluid through them, they would always eventually bind with some tiny piece that flaked off. I always ended up mad at myself for the ten gallon flush when I should have just bought the new lines and saved time and frustration, but certainly not money- as you mentioned. I could just never get them clean.
By binding, are you saying that the brake pads are dragging excessively without applying them? How hot are they getting? If you are talking about your brakes dragging excessively, then I don't see how new brake lines would help this problem. Maybe I am not understanding. You are probably aware of this, however, rapid front tire wear can be caused by many things, including: riding style, hard braking, type of tire, suspension setup, and sometimes just a certain type of tire on a certain bike.
thanks - I need to be careful how I explain things. You're right - I mean that the brakes are dragging without being applied. After about 15 miles of urban riding finishing off with a mile at 70+ mph the disks are too hot to touch (having stopped very gently so as not to warm them up by aggressive breaking). What makes me think they're dragging? 1. If I try to spin the front wheel it is far harder to spin than the back wheel - if I push the pistons in by pressing the caliper against the disk and then releasing the caliper, the front wheel spins freely. 2. The front tyre is significantly hotter than the rear tyre after a normal (not fast) ride 3. fuel consumption up (tank empty in 170 miles when used to be 185 miles). I can't see why the hoses would cause the brakes to drag but I don't know what else to try. The calipers slide easily on the rods and the pistons move easily in their cylinders. Any thoughts? Phil
When you put the new pads on, how hard was it to fit calipers (with the new pads) back on the rotor? I mean, was it a very tight, like a vise? I am wondering if the pistons are retracting far enough back into the caliper. The pads should be the right ones, (and not too thick) if they are genuine Honda parts. So, did the brakes drag before you starting replacing parts? How many miles are on these pads? When pads are first replaced, they usually need a 100 or so miles to break in, and are usually a little tight, and might drag a little more than usual, however, not as much as you describe usually. Maybe once the calipers heat up enough it is causing the pistons and/or slide rods to bind/stick. Or maybe it is time for some new calipers because something has to be binding. Sorry I cannot be of more help. Maybe somebody else can suggest something.
brakes Hi Jason The calipers were fiddly to fit on with new pads and new disks but once on they were not tight. It took a couple of squeezes of the lever to get any resistance suggesting that the pistons had to come out a little way first. I was rather hoping that the brakes would bed in as you suggest but have two rides totalling 500 miles coming up and so wanted to be sure that all was OK. Having just replaced a tyre as well as disks and pads, don't really want to wreck any of them by ignoring a problem. Thanks for your suggestions. Phil
thanks - may yet replace the hoses but have already had to replace the exhaust system, disks, seals and pads this year and the printed circuit for the clocks and lights etc last year (about £1250 in total) so would prefer not to spend money without a very clear idea that I'm fixing the real problem. Phil
did you replace the rings, or seals that are around the piston on the caliper, if the bike sat for a while, those may have lost their "spring"? You can manually move them easily enough, but they aren't moving on their own? Just a guess though, so take it with a grain of salt. I would say you have to look at what causes the pistons to retract. Trying to remember from my motorcycle repair class so many years ago...
Spike might have a point. I totally understand not wanting to sink any more money into a bike which you have dumped a ton.
Ten gallons of brake fluid?? Is that a figure of speech? Man, that is a LOT LOT LOT of fluid. Ten gallons of brake fluid must have cost a fortune.
Hi Spike, Yes, when I discovered the brakes were binding and I also needed new disks and pads I realised that I really needed to clean up the pistons and replace seals at the same time. So both dust and main seals have been replaced for new and the corrosion that builds up in the seal recesses (a white powder) has been removed carefully. The bike hasn't been sat around either before or after, so I don't think that's the problem. thanks Phil
Is the brake fluid reservoir overfilled? If it was at the proper level before you replaced the pads pushing the pistons back enough to fit the new ones may have caused it to be overly full. As the fluid warms up, and without any room to expand in the reservoir, it pushes agains the pistons. I haven't experienced this myself but the info was passed along by a guy who is a pretty good wrench.
I would suspect the return in the master cylinder before brake lines. There's a small hole which allows enough fluid to move through and let the pads retract. This could be your issue.
OK, that had been just a thought. You had mentioned seals being replaced, but not which ones. So I took a guess. What else causes the pistons and thus the pads to retract??? could it be that the pistons are retracting, but the pads are not? That they aren't in there correctly? Are all the pads sticking, or just one side? Does the release of the brake lever, cause any suction in the system which helps to retract the pistons? I don't think so, but if it did, and the spring or a seal in your master cylinder was bad??? or blocked somehow... do they bind when the bike is cold? Meaning not ridden? Or just after it has been ridden a while?
I just had a thought. If I'm not mistaken, you have linked brakes, right? Basically your front brake is ALSO tied to the rears, and all the lines and reservoirs associated with it. If one of your rear brake master cylinders is binding up, it'll send pressure to the front brake as well. What I'm trying to say is you can't just look at the 'front' braking system as the whole thing is tied together. Try doing a full system bleed, even at the fittings under the seat. That many miles is sure to have some pretty nasty fluid. And another thing, is your rear brake pedal adjusted properly? How about the weird slave cylinder that compresses with the front braking force...
