useless front brakes

M

mark1971

Registered
My front brakes on my 2000 model are absolutely rubbish. I can easily pull the lever right into the bar and thats on the hardest setting on the adjuster knob. I've stripped the calipers down and cleaned all the pistons and replaced all the caliper seals on both sides. I've replaced the master cylinder piston and seals and re bled the whole system loads of times. The hoses are Goodridge braided lines and i've even removed and tilted the whole lever so that any air trapped in the master cylinder will escape back into the reservior when you pull the lever in slightly. Nothing has made any difference to the woefully inadeqate brakes that i currently have. Can anyone help with something i might be missing. I've spoken to a tech guy at Suzuki uk who reckons there may be some air trapped in the calipers and that i should remove them and move them above the lever and see if that allows the air out??? I am now thinking of replacing the standard 6 pot Tokicos with some 4 pot Nissin calipers off an earlier GSXR750 as i believe these fit straight on, 90mm spacing between mounting holes. I read that the 6 pot calipers flex quite a bit, is this true?
Any info greatly recieved.......

Mark
 
Upgrade to a Brembo master cylinder...for the 6 pot calipers you need the 19x20 unit :thumbsup:
 
If you've rebuilt and replaced all the seals in your front braking system, bleed everything right, and are using new fluid then there shouldn't be a problem unless you've got a serious leak some where in the system. Your brake system is a mechanical system. Check the whole system for fluid leaks. Yes there is some flex in the calipers if you measure it with a micrometer. It's nothing extreme to make the lever feel spongy.
 
if the brakes are that bad, there is something else wrong.. either the pads themselves are screwed up (glazed or contaminated) or if you can pull the lever to the handle bar, air in the system..

if the handle is firm to the pull, you need to deglaze the rotors and pads with some 200 grit paper (this is "deglaze" as in take the shine off, not grind them down)

if that does not suit your needs, put some better quality pads on.. for the ultimate in braking power (power brakes) you can get the EBC HH pro Extreme pads (PM GoldenChild, he has a smoking price on them) and they will give you 2 finger stoppie power.. (I think they are a bit too much on the street if you are not really used to them)

I run the Pro Exteme pads on the track and I can get the front tire up to point of lockup running well into the triple digits..

The adjustment wheel you are talking about has nothing to with stopping power per sey.. it is to adjust the handle so it does not bottom out against the handle bars before applying full lever pressure to the master cylinder.. This is so you can adjust the stopping point to a position you are comfortable with (I like about 1" on the street and 2" on the track)

Honestly the brakes on these bikes are intentionally a bit soft. I think this is done due to the number of riders that have little or no experience on these types of bikes and keeps them from getting into trouble in panic stops.. If you go with the HH Extreme? I can promise you will not need any more braking power.. (assuming they are installed and bedded correctly)
 
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Mr Bogus said:
if the brakes are that bad, there is something else wrong.. either the pads themselves are screwed up (glazed or contaminated) or if you can pull the lever to the handle bar, air in the system..

if the handle is firm to the pull, you need to deglaze the rotors and pads with some 200 grit paper (this is "deglaze" as in take the shine off, not grind them down)

if that does not suit your needs, put some better quality pads on.. for the ultimate in braking power (power brakes) you can get the EBC HH pro Extreme pads (PM GoldenChild, he has a smoking price on them) and they will give you 2 finger stoppie power.. (I think they are a bit too much on the street if you are not really used to them)

I run the Pro Exteme pads on the track and I can get the front tire up to point of lockup running well into the triple digits..

The adjustment wheel you are talking about has nothing to with stopping power per sey.. it is to adjust the handle so it does not bottom out against the handle bars before applying full lever pressure to the master cylinder.. This is so you can adjust the stopping point to a position you are comfortable with (I like about 1" on the street and 2" on the track)

Honestly the brakes on these bikes are intentionally a bit soft. I think this is done due to the number of riders that have little or no experience on these types of bikes and keeps them from getting into trouble in panic stops.. If you go with the HH Extreme? I can promise you will not need any more braking power.. (assuming they are installed and bedded correctly)
Click to expand...


What he said. :thumbsup:
 
What bogus said. Also, get you a speed bleeder so you can suck the fluid out of the resevoir. The symptoms sound like you have lots of air in the system. Also, we had a problem with Demmyms bike when the crush washer was not sealing well. It did not leak fluid, but it sucked air in the bleeder valve. We fixed it by finding that leak. Good luck.
 
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YOU HAVE AIR IN THE SYSTEM!

Are you listening? :poke:

You need to get the air out of the brake lines. You said you replaced the lines with Goodrich braided lines, so you must have the dual lines to the front calipers. (Nod yes) You need to get the air out of the top of the brake lines. You can bleed it out conventionally. You need to move the fluid in from the bottom to get it done the easy way.

Go find a fuel mixing syringe from a bike shop. Put a short length of hose on it that will seal on the bleeder valve. Fill it with clean brake fluid and make sure it has no air in it. Crank the bleeder valve loose a small amount. Gently push the syringe plunger down about an inch. Draw the plunger back out the same amount and check for bubbles coming out caliper. When the bubbles are at the top of the syringe you can push some more fluid into the caliper. While there is pressure on the caliper you need to crack the banjo bolt at the top of the brake lines. You should hear the air escape. Leave it loose until the fluid it seeping out, then tighten it back down. Do this to both sides. Once both side are done, check the brakes and bleed until the lever pressure is at the desired effort.

:beerchug:
 
and to be PC.. your brakes are NOT a "mechanical" system, they are a "hydraulic" system..

Mechanical brakes went out in the 60's and 70's on bikes and in the 40's and 50s on cars..

easy to spot, cables, linkages etc... hydraulics use hoses... :)

1974-mv-agusta-750-gt-5.jpg
 
Good luck to you and :welcome: to the org.
Lots of good info here.
Ride safe.
Bubba
 
Cheers for the quick response guys. The pads were also changed when i did the strip down and the guy from Suzuki tried the loosening the banjo bolt at the end of the master cylinder trick with no success and also checked the fluid at the bleed nipples and said it was running totally clear. I mentioned to him that i had noticed dampness at the bottom of one of the calipers and whether air could be being sucked in from somewhere on the caliper but he said that the hydraulic force would push fluid out if there was a leak on the caliper. Think i'll whip the whole brake off the bike and dismantle it and re check everything is ok then start again to try and improve it. I'm still thinking there might be some mileage in using some GSXR nissin calipers instead, has anyone else fitted 4 pots and if so what are they like ( not including Brembo's in the 4 pot question ).

Mark
 
Mark just a thought here on the piston seals. Shop manual says there's only one correct way to install them. They can be installed 180 degrees out. Check your seals to see if theres a beveled edge on them. That's the side that goes towrds the piston. Pistons should have to be "pushed" into the bore. They are very snug fit. Anything else and you have the seals in wrong and you won't build pressure. There's a shop manual hosted somewhere ask one of the guys to put you onto it. Hope this helps. Wardie
 
Good call Wardie, i'm going to rip them apart and start again and i wasn't aware of this bevelled edge. When i popped the new seals in i just sized them up and stuck them in so that could well be the issue i have.

Mark
 
Mr Bogus said:
and to be PC.. your brakes are NOT a "mechanical" system, they are a "hydraulic" system..

Mechanical brakes went out in the 60's and 70's on bikes and in the 40's and 50s on cars..

easy to spot, cables, linkages etc... hydraulics use hoses... :)
Click to expand...

I dont even know what to say about this statement... "your brakes are not a mechanical system..." Wow... I am an aircraft mechanic, and please let me assure you - Your brakes ARE a mechanical system. Hydraulics are simply the means to operate a mechanical (or electro-mechanical) device. Hydraulics take the place of the cables, bellcranks and/or control rods. Your braking system consists of mechanical components, operated by a hydro-mechanical actuation system.
 
brakes on bikes and cars are referred to as either Mechanical or hydraulic.. nomenclature is a *****..

they are all parts of machines... just like an airplane has a chassis with body panels and motor...
 
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You either have air in the system, or the system's not holding pressure.
 
Mr Bogus said:
and to be PC.. your brakes are NOT a "mechanical" system, they are a "hydraulic" system..

Mechanical brakes went out in the 60's and 70's on bikes and in the 40's and 50s on cars..

easy to spot, cables, linkages etc... hydraulics use hoses... :)
Click to expand...

thank you Mr. Clavin

ratzenbergergx7.jpg
 
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