Suzuki GSX-R Motorcycle Forums Gixxer.com banner

1 - 12 of 12 Posts

·
Registered
Joined
·
16 Posts
Discussion Starter #1
I've searched the forums but am unable to get an answer.

I've got a srad track bike and on my last track day the brakes were playing up, after a few laps they'd get warm and pull back further and further the hotter they got, it's
got 4 pot tokicos and i've just rebuilt the master cylinder and calipers with new seals etc, new braided lines with fresh copper washers, i have even replaced the bleed nipples and i can't get a decent bleed.

I done these the same as i do all my brakes from empty Back bleed with a big syringe then traditional bleed them from then on.

Also i bled at the banjo at M/S, calipers off and above M/S.

I'm not getting any more bubbles from caliper, and levers still crap anyone got any ideas or had similar problems and found the problem?
 

·
Premium Member
Joined
·
3,573 Posts
I've searched the forums but am unable to get an answer.

I've got a srad track bike and on my last track day the brakes were playing up, after a few laps they'd get warm and pull back further and further the hotter they got, it's
got 4 pot tokicos and i've just rebuilt the master cylinder and calipers with new seals etc, new braided lines with fresh copper washers, i have even replaced the bleed nipples and i can't get a decent bleed.

I done these the same as i do all my brakes from empty Back bleed with a big syringe then traditional bleed them from then on.

Also i bled at the banjo at M/S, calipers off and above M/S.

I'm not getting any more bubbles from caliper, and levers still crap anyone got any ideas or had similar problems and found the problem?
welp if you are not trying to invest in a pressure system then I would try gravity, crack it and let it drain out, keeping the master full obviously.. if it doesn't pump bleed then something is typically amiss? a good system typically bleed right up, could be your banjo or bleed screw is dirty or whatever not closing all the way?

my self I wouldn't ride a system that wont master bleed, just me tho, I clean everything up if its acts up like that, had one 4x4 truck get dirt in the bleed screw, cleaned er up all good, however if its something else worn that's allowing air back in seals or something you prolly wouldn't want those in charge of stopping you from 165 down to 23 for a tight turn.. one wouldn't think you would anyways?

you already cracked open the system whats it going to hurt to clean and inspect?
 

·
Registered
Joined
·
178 Posts
I bet it is... man bolt right up brake light and all? that's radial right?
Bolt on ok, needs to be raised slightly to clear nose fairing. Brake light good. Have to fit with HEL adapter ( different bolt thread ) keep srad brake lines, radial yes. The srad mc are old and tired, tried a few then new seal kits etc, but wasted money.
 

·
Registered
Joined
·
16 Posts
Discussion Starter #6
Twistedmister, the system has already been stripped and cleaned when new seals are fitted, who wouldn't clean seal seats when fitting new seals. Also has new bleed nipples
 

·
Registered
Joined
·
178 Posts
Twistedmister, the system has already been stripped and cleaned when new seals are fitted, who wouldn't clean seal seats when fitting new seals. Also has new bleed nipples
I would suggest Twistedmister is trying to help, as per your original post. Some do not do as he suggests ( for whatever reason, known only to them ).
 

·
Registered
Joined
·
15 Posts
This might have been done already, so please excuse me if it has. This might help someone else with the same issues. You said you rebuilt the calipers with new seals, but didn’t mention new pistons or surface condition of both pistons and calipers. I’ve seen corrosion not addressed and new pads can cause binding. This is just because the pistons are now further in the caliper bore. You can put a piece of plywood into the calipers, compensate for pad and rotor thickness. Remove the pads, insert plywood, and squeeze. The pistons should all have identical depressions in the wood. If they are not, then chasing an air bubble is futile. To make sure you got the banjo at the MC cleared, and to find a rogue bubble, zip tie your brake lever so it’s just before applying brake pressure. It needs to be in that dead spot. Leave it on over night. Bubbles in the lines, or banjo should work their way into the reservoir with this method. The best way I’ve found to figure out if lever collapse is air, a bad MC seal, or piston binding, is when you feel that fade, let off and back on the brakes, pumping them. If it’s still soft, then your issue is not air. Good luck and let us know what you find!
 

·
Registered
Joined
·
16 Posts
Discussion Starter #11
This might have been done already, so please excuse me if it has. This might help someone else with the same issues. You said you rebuilt the calipers with new seals, but didn’t mention new pistons or surface condition of both pistons and calipers. I’ve seen corrosion not addressed and new pads can cause binding. This is just because the pistons are now further in the caliper bore. You can put a piece of plywood into the calipers, compensate for pad and rotor thickness. Remove the pads, insert plywood, and squeeze. The pistons should all have identical depressions in the wood. If they are not, then chasing an air bubble is futile. To make sure you got the banjo at the MC cleared, and to find a rogue bubble, zip tie your brake lever so it’s just before applying brake pressure. It needs to be in that dead spot. Leave it on over night. Bubbles in the lines, or banjo should work their way into the reservoir with this method. The best way I’ve found to figure out if lever collapse is air, a bad MC seal, or piston binding, is when you feel that fade, let off and back on the brakes, pumping them. If it’s still soft, then your issue is not air. Good luck and let us know what you find!
Thanks, I've since narrowed it down to the master cylinder, despite having been rebuilt new seals etc it's still no good. Just going to swap it out for a radial off a newer model
 

·
Registered
Joined
·
178 Posts
Thanks, I've since narrowed it down to the master cylinder, despite having been rebuilt new seals etc it's still no good. Just going to swap it out for a radial off a newer model
Be sure to get the recall one, where the reservoir attaches to the top of the mc and not to the side ( many are selling them, they are flawed,bought one myself ). Any questions or help let me know, will get photos.
 
1 - 12 of 12 Posts
About this Discussion
11 Replies
5 Participants
sradmad600
Suzuki GSX-R Motorcycle Forums Gixxer.com
A forum community dedicated to the Suzuki GSX-R motorcycle. Discuss the GSX-R600, GSX-R750, GSX-R1000, and GSX-R1100, and more!
Full Forum Listing
Top