Weak Front Brakes (I searched) ?

[nelson8708]

I bought this bike last week and the previous owner had the calipers off when i first came to look at her; he was in the middle of rebuilding them. The second time i went to look at her / test ride her he had the calipers back on but, said there was some air still in the system and that was why the front brakes were weak. I've spent probably 2 hours bleeding the system to no avail. I've gone through half a bottle of brake fluid (big 32 oz boy). First, I was just bleeding at the calipers with a home made vac tool. After that i went the old fashion way with pumping the MC and cracking the bleeders. Still didn't get better so after some research i cracked the banjo bolt at the MC to see if air was trapped there. Then cracked the 2 banjo bolts at the splitter and finally the lines where they bolt to the calipers. After all that i used the syringe trick to pull a vac on the bleeders. Still have a crappy brake feel and i can pull the handle all the way to the grip. I did notice when using the syringe trip i was getting bubbles from all the bleeders but, i believe it was air getting pulled through the threads of the bleeder when loosened because all the bleeders did it. When i bleed them the old fashion way i dont get any bubbles. I have about 1/8" to 3/16" of pad material left so i'm going to go ahead and order new pads. I also noticed that after taking her for a quick spin there was what looked and felt like a light glazing of grease on the front rotors, maybe when the previous owner had the brakes apart the pads got oil or brake fluid on them? What should i try next?

I'd like to have front brakes....Help

Thanks,
-Nelson

[wickeded]

I have the same problem, from what I have read and tried it just air trapped in the system. I will take some time to get it all out. I bled the system for over a week at least an hour a day and went trough several containers of brake fluid before I started making any progress. It better but not 100%, more bleeding.........
http://katriders.com/vb/showthread.php?t=107796

[Black_peter]

OK first off what year?
Second: what work was the PO doing?
Third, and I can't say this enough, proper bleeding with quality fluid is key.
Using half a bottle of crap fluid does you no favors.

Know this: (shout out to CP there)
Stock brake lines should get changed 4 years after model year (that is if you have a 2006 bike, time to change the lines) bad lines will never work right.

Castrol LMA is the best fluid IMO, at under $4 it is a bargain. Your brakes are the most important part of the bike, why skimp on a $4/year item?

Rebuilding calipers is a pretty simple job, 98+ are even easier. It takes about 30 minutes to strip them, an hour to clean and 15 to 20 minutes to re-assemble. The parts kit will cost you $15-20

Air in the master cylinder will be hard to pump out and will dog you. cracking the line at the MC while squeezing the lever and "bleeding" them slightly can work miracles.

After market lines (like HEL from member HS2020) are several times better than brand new stock lines, and 1/3 to 1/5 the cost.

The trick of tying the lever to the grip works, but might not be a permanent fix. Pump the lever, pull it to the grip and wrap some cord around it to hold it to the grip over night.

[nelson8708]

OK first off what year?
Second: what work was the PO doing?
Third, and I can't say this enough, proper bleeding with quality fluid is key.
Using half a bottle of crap fluid does you no favors.

Know this: (shout out to CP there)
Stock brake lines should get changed 4 years after model year (that is if you have a 2006 bike, time to change the lines) bad lines will never work right.

Castrol LMA is the best fluid IMO, at under $4 it is a bargain. Your brakes are the most important part of the bike, why skimp on a $4/year item?

Rebuilding calipers is a pretty simple job, 98+ are even easier. It takes about 30 minutes to strip them, an hour to clean and 15 to 20 minutes to re-assemble. The parts kit will cost you $15-20

Air in the master cylinder will be hard to pump out and will dog you. cracking the line at the MC while squeezing the lever and "bleeding" them slightly can work miracles.

After market lines (like HEL from member HS2020) are several times better than brand new stock lines, and 1/3 to 1/5 the cost.

The trick of tying the lever to the grip works, but might not be a permanent fix. Pump the lever, pull it to the grip and wrap some cord around it to hold it to the grip over night.

1- 94' kat 750
2- he said the calipers felt like there were sticking so he rebuilt them
3- Do I start from the bottom and work my way to the top when bleeding or oppisite?
4- I'm using valvoline syn brake fluid
5- I'll change the lines if i must but, would not like to start throwing money at it until i know that is the problem
6- Castrol lma (next year when i flush the brakes i'll use it)
7- Calipers should be rebuilt by the PO
8- Never saw any bubbles when i cracked the line there (did it 5 times or so
9- If I end up by process of elimination finding that she needs new lines i can have some made at a local race shop (should i get them in -3 or -4 size SS braided line?)
10- I'll try that trick tonight and see if it works. What do you mean its not a permanent fix? If it helps pull the air to the the top maybe a quick bleed at the MC will make it permanent.

Hope this helps some one point me in the right direction.

Thanks,
-Nelson

[steves]

It's probably just an air bubble in the distro block if he kept the stock lines on the bike.

Loosen the MC cap, and tie the handle back, leave it over night.

Get a friend to help you and pump the lever gently while 'tapping' on the brake lines with a screw driver or something. Then carefully bleed the brakes again.

Make sure not to open the bleed screw so far that it sucks air in through them!

Bleeding with the stock distro block is a big huge PITA.

[Black_peter]

1- 94' kat 750
OK so follow this: http://katriders.com/vb/showthread.php?t=60280
And maybe this http://katriders.com/vb/showthread.php?t=64395
2- he said the calipers felt like there were sticking so he rebuilt them
Yeah but did he? One mans rebuild is another mans who knows what... In short did he have a clue what he was doing??
3- Do I start from the bottom and work my way to the top when bleeding or oppisite?
Yes.. What ever works
4- I'm using valvoline syn brake fluid
5- I'll change the lines if i must but, would not like to start throwing money at it until i know that is the problem
You have 17 year old brake lines. No matter how you slice it changing them is not a waste. You know I panic braked in my car once and blew out both front lines and the MC..
6- Castrol lma (next year when i flush the brakes i'll use it)
7- Calipers should be rebuilt by the PO
(see #2)
8- Never saw any bubbles when i cracked the line there (did it 5 times or so
You won't see bubbles at the MC if that was what you mean..
9- If I end up by process of elimination finding that she needs new lines i can have some made at a local race shop (should i get them in -3 or -4 size SS braided line?) After market lines are generally slightly smaller ID than OEM.
10- I'll try that trick tonight and see if it works. What do you mean its not a permanent fix? If it helps pull the air to the the top maybe a quick bleed at the MC will make it permanent.
It can indicate you have air in there and help it move it along, but I still needed to bleed the brakes after doing this.

Another point is the MC it'self, It could be gone and needs rebuilding.

[Trackerrrr]

Changing out your lines for SS ones makes a big difference. The original lines on my '89 would visibly swell when I squeezed the brake lever. Changed them to HEL SS lines (thanks again to HS2020) and the feel was so much better. New stock lines will cost much more than SS lines and still have to be changed out in four years.

[nelson8708]

I'll keep that in mind. I talked to a shop race shop today and they said they would make the lines for about 60-70$. If i decide to go ahead and do it i'll go with a two line setup to get rid of that stupid splitter block.

Could i use the long banjo bolt from the splitter in the MC when going with the two line setup?

-Nelson

[Black_peter]

[QUOTE=nelson8708;1939807

Could i use the long banjo bolt from the splitter in the MC when going with the two line setup?

-Nelson[/QUOTE]
yup

[wcj]

These work pretty good too for bleeding the MC.

[LAsunbird86]

^ Link?

[sonosam]

I was just reading in Truckin' magazine about a trick that involved hitting the MC with a rubber mallet to help "persuade" the air out. Not sure it needs to be that drastic with the bike, but it may help in your situation. The tip came from the folks at SSBC.

Marc

[nelson8708]

I tapped on the handle bars as i was bleeding them yesterday to help get any air that might be in there out. I also did the tie the lever to the grip trip and when i went out in the garage this morning and untied it there was no pressure left in the lever until i gave it a few pumps (master cylinder rebuild?). Going to order new pads some time this weekend.

-Nelson

[neoxxt]

Funny you're going through this. I loved my Kat before I began taking it apart and "upgrading" things. I've never gotten it fully back together and just ended up buying myself another bike. I'm trying to get it back in riding shape so I can sell it off. Last year I fought with the front brakes for so long, I ended up riding it for 2k miles with hardly any lever feel.

I'm in the same boat as you right now, only I've rebuilt the calipers myself, installed Goodridge SS lines and rebuilt the MC. I've pumped no less than 5 bottles of fluid through the system, have no bubbles showing and have tied the handle to the bar. I'm using Prestone DOT4 from Autozone, because it's convenient, but I have a hard time believing that is the root of my problems. I back filled the calipers tonight. (Mind you got brake fluid all over my new Conti Road Attacks..) And started from scratch. I left one of the bleeders open and began to pump, just for the hell of it. It wasn't pushing anything through. No air, no fluid. I left the handle ziptied to the bar again tonight with it on the side stand. The only other thing I can think of is that the Goodridge kit didn't come with all of the correct banjo bolts. One caliper was a fine thread, while the other was coarse. I used stock on one side and included bolt on the other. I may buy another bolt kit from Goodridge and start there. I have to get this thing out of my garage and hopefully not at a loss. I'm so tired of throwing money at it. Let me know what works out for you..

[Black_peter]

Oooo OK using two different thread pitches is not a good idea..