"Grabby" front brake?

[goose491]

Okay, I don't know how to acurately describe what it is I'm feeling so this might be quite funny. Any help is greatly appreciated though.

I noticed that the front brake sorta has this interval of sorts. This is my first bike so I wouldn't have known the difference but for my friend riding it and mentioning something. Now that I've ridden his, I definately know what he's saying. It's like what a warped rotor feels like on a car when you brake. My rotors are not warped, and I don't feel like my ability to stop is hindered...

I can't truly find the words to describe it, other then to say: It's like, when I use my front brake, I come to a "Sto-ah-ah-ah-op", rather then to a "Stooooop".

I hope that makes sense. lol. Any ideas, suggestions?

[katana bob]

are you sure the rotors are true? are they clean? sometimes some surface rust can form but a few stops should remove it. how old are your brake pads? does the brake lever feel firm throughout the stop?

[The CyberPoet]

My guess is that you have a caliper piston that is sticking or the hoses have seen their four-year lifespan come & gone, based on your symptoms, although it may be as simple as road-grime on the rotor. Since you haven't posted your ride profile, I can't begin to guess on the model/age/etc.

I'd start by cleaning the rotors with either spray brake cleaner or with windex on a paper towel (repeat until the paper towel doesn't come away dirty). Make sure you rotate your tire while you are doing this, to get every bit of the rotor, and avoid spraying brake cleaner into the front wheel bearings (part of why I prefer the windex solution).

If that doesn't cut it, it's time for a proper caliper rebuild & hose-swap. Order new seals, SS-sheathed lines, get a liter of fresh brake fluid (DOT 4, I prefer Castrol GT LMA, or Valvoline PowerSynth as a back-up if I can't find the Castrol), and optionally some speed bleeders. If the pads are within 25% of their useful life or glazed, now is a good time to replace them as well. Then go search through the mechanics section on how to do a caliper rebuild (not as complicated as it sounds -- disassemble, clean some parts, replace a couple seals, reassemble).

Cheers,
=-= The CyberPoet

[goose491]

To the eye and to the touch, the rotors are nice and smooth. There is some of that "funky grooving" in them, but it's along the direction the pads would move... not perpendicular (do you know what I mean?)

I was told the pads were new when I bought the bike in May of last season. I guess I thought that's why it was doing it. I got used to riding like this and only recently did my friend ride and mentioned it.

Brake lever feels firm through the stop yeah. So whatever it is, it's not translating itself back through the system to my hand.

[The CyberPoet]

You still didn't answer the question about the age/make/model, but the answers are in my post above.

Good Luck!
=-= The CyberPoet

[goose491]

I was typing to katana bob at the same time you were typing to me.

Thanks CP, it's not grime on the rotors, I'm sure of that.

I'll fill out the profile but in the meantime it's a 93 Kat 600 with roughly 43000kms. The brake pads are new last season but I have no idea about the calipers and such.

Nick

[The CyberPoet]

Hoses, caliper seals, caliper rebuild. Check the pads while you're down there. It's either the hose age (expanding under pressure) or the caliper pistons sticking. Might as well fix both since your brakes are the same as your ability to stay alive

Actually, with a bike that age, it could be the master cylinder pump seal as well. I'd replace it as well just to be sure (I don't go cheap on brakes -- parts are cheap and if it avoids a single mishap, worth every penny).

Cheers,
=-= The CyberPoet