How do you know when to rebuild/replace brake parts?

[electriKAT]

I recently bought a '91 Katana 600. I have no idea what work has been done on the brakes, but they don't work too well. I read through the "how to" on rebuilding, and I figure I will at least need to replace the fluid and clean the lines out. My question is, how do you know when the lines need to be replaced? Can you tell just by looking at them?

Also, I found the min disc rotor thickness in the manual, but I do not have a micrometer. Is there a "poor man's" way of checking this?

Thanks.

[tmk7c9]

If they're dried up and cracking, i'd replace the lines. Otherwise, i'd bleed them well, clean everything out, make sure nothing leaks, and they work as they should (hard to define sometimes). If you can't get the lever to firm up, a master cylinder rebuild may be in order. Brake pads may be needed if they won't bite but the lever is firm (after almost 20 years, brake pads may be needed anyways.)


You don't need a micrometer to measure calipers, just get a set of calipers. I bought a set of digital calipers from harbor freight years ago for $20. Sure, they're cheap, and I wouldn't trust them to measure stuff on a space shuttle. But for the average home mechanic, they work great.

[Kreylyn]

I recently bought a '91 Katana 600. I have no idea what work has been done on the brakes, but they don't work too well. I read through the "how to" on rebuilding, and I figure I will at least need to replace the fluid and clean the lines out. My question is, how do you know when the lines need to be replaced? Can you tell just by looking at them?

Also, I found the min disc rotor thickness in the manual, but I do not have a micrometer. Is there a "poor man's" way of checking this?

Thanks.

OEM recomends replacing all brake lines every 4 years (unless you have aftermarket lines rated for longer), or if they show signs of cracking.

You can get a really cheap micrometer from harbor freight that will work (1-3$).

Krey

[md86]

Best thing I ever did for my brakes (with old stock lines )was HH pads and fresh fluid ....

[electriKAT]

Thanks for the advice. Really, every four years? Any recommendations on where to go? Online or dealer? Are HH an aftermarket brand of brake pads?

[Kreylyn]

Thanks for the advice. Really, every four years? Any recommendations on where to go? Online or dealer? Are HH an aftermarket brand of brake pads?

Stainless steel braided lines will last significantly longer. There are a few people that offer them on the boards, and are more than worth it when you replace the lines.

"HH" is more of a grade of pads, and work really well for the fronts. A bit of overkill for the rear wheel (and can quickly cause the rear tire to lock up) so normally not the best unless your needing them for track purposes. There are also a few vendors that can help you with picking a good brand of brakes as well.

And their prices will be comparable or alot better than local guys in most cases.

Krey

[riffer]

Thanks for the advice. Really, every four years? Any recommendations on where to go? Online or dealer? Are HH an aftermarket brand of brake pads?

I'd take that recommendation with a large pinch of salt.

Better advice would be this:

Every 12 months, or 3000 miles (or 5000 kilometres where I live), take the calipers off the bike.

Take out the pistons and piston seals.

I clean out the entire caliper and remove everything. Take out the piston seals and clean out everything with brake fluid and an air compressor gun.

Then check the pistons for any pitting or rusting. If they're a bit rough you can clean them up with some 1500 wet/dry sandpaper but be careful not to scratch them.

Check the piston seals for any wear - if they're no good replace them; otherwise you can get away with re-using them.

Then put the seals back in and coat them with rubberlube or similar rubber lubricant, and gently push the pistons back in so that you don't damage the piston seals.

Clean up your pad locating pins using the sandpaper to make them nice and smooth.

Put the calipers back on the bike, then put the new pads in, and put a thin smear of grease on the pad locating pins so that the pads will slide nicely.

Use a copper anti-seize on the pad locating pins to ensure that they won't be a problem taking out next time.

Then connect the brake hoses and fill up the brake master cylinder with new fluid and gently pump through to the end. Bleed the normal way.

[cleankat96]

I'd take that recommendation with a large pinch of salt.

Better advice would be this:

Every 12 months, or 3000 miles (or 5000 kilometres where I live), take the calipers off the bike.

Take out the pistons and piston seals.

I clean out the entire caliper and remove everything. Take out the piston seals and clean out everything with brake fluid and an air compressor gun.

Then check the pistons for any pitting or rusting. If they're a bit rough you can clean them up with some 1500 wet/dry sandpaper but be careful not to scratch them.

Check the piston seals for any wear - if they're no good replace them; otherwise you can get away with re-using them.

Then put the seals back in and coat them with rubberlube or similar rubber lubricant, and gently push the pistons back in so that you don't damage the piston seals.

Clean up your pad locating pins using the sandpaper to make them nice and smooth.

Put the calipers back on the bike, then put the new pads in, and put a thin smear of grease on the pad locating pins so that the pads will slide nicely.

Use a copper anti-seize on the pad locating pins to ensure that they won't be a problem taking out next time.

Then connect the brake hoses and fill up the brake master cylinder with new fluid and gently pump through to the end. Bleed the normal way.

I would think by taking the pistons out you would damage them very easily especially doing it every year and i would never put a piston back in with the same seals- Just my .02 cents

[Black_peter]

You don't need a micrometer to measure calipers, just get a set of calipers. I bought a set of digital calipers from harbor freight years ago for $20.

Good advice there. You're either at the minimum thickness or you're not. being off by .2mm is not going to kill you..

I would think by taking the pistons out you would damage them very easily especially doing it every year and i would never put a piston back in with the same seals- Just my .02 cents

And you would be right. Every time you remove the pistons there is a chance of damage. I have rebuilt lots of calipers and haven't damaged one yet, but that day might come. CP would use a bicycle pump to pump air into the caliper. That will push out the pistons. Then after you split the halves you should be able to get them out by hand. I'm a cowboy about it but I have been doing work like this for 30 years.. Sorry but I disagree with a lot of what riffer posted.
Follow my rebuild write up. It might take some time, but shortcuts like sand paper? Nope sorry..

This is one of those sad days, because CP would have all the exact data posted by now. *sigh*.

Stock brake lines are good from 5 years after manufacture. Have a 2005 Kat? It was made in 2004 so you need new lines. This is what Krey said, I just want to clear that up because some might say 5 years based on model year..

After market lines from a good manufacturer are lifetime warrantied. I would go with HEL (from HS2020) because it is a superior product. End of Story.. I have Goodridge's and they are a good line, cheaper than HEL but not as good. You get what you pay for and the price difference considering it is a one time purchase is pretty small.

Cyberpoet would say anytime you push the pistons back into the caliper you should rebuild the caliper. I think that is a little excessive, a little.
Bottom line, in my very experienced opinion:
If you have any questions about whether the work was done, do it.
On a 91 I can guaranty they need rebuilding. If for no other reason than they need a good cleaning and you don't want to put 17 year old seals back in.

Brake fluid (again nothing humble about my opinion on this!) should be changed 2 times a year if you ride year 'round. Or live in humid climate or ride a lot. Every season if you ride summers/nice days only. CP and I both swear by Castrol LMA. Again on price; you will use $4 of brake fluid to flush/replace the fluid. 2 times a year, so for $8 a year why bother putting $2 Pep Boys fluid in there? Castrol LMA is super clear, so the second you see the fluid, change it. (read my brake bleeding write up)

Brake pads. They have wear lines. A groove is cut in the pad, if the groove is tiny or gone? New pads.. I like EBC HH; I like the feel and they set well with a very progressive bite.

The braking system on your bike is the most important thing period!
Take it seriously, don't cheap out/skimp and you should get years of good braking with a tiny bit of maintenance..

[ctandc]

I agree with BP.

But to be honest it's more than likely going to a be a moot point, once you pop off the front master cylinder cover.

The fluid will probably be BROWN...and that crud is now in every nook and cranny of the lines and the calipers.

[Black_peter]

To pimp my threads:
Flushing

http://katriders.com/vb/showthread.php?t=60280

Rebuild

http://katriders.com/vb/showthread.php?t=64395

[electriKAT]

Thanks for all of the great information. I have not done this yet as I am still working on the bike. The sticky "how to" threads are perfect. And I looked at MOpowersports website. Thanks again.