brake lever travel

This one has puzzled me for years . Why is it that as my front pads wear,the distance that I have to move the lever increases until it gets uncomfortably near to the grip? I have experienced this on my GSXR 1100 L ( 4 piston ) and my GSXR 1100 WP ( 6 piston ) In both cases I have had braided brake lines and everything has been in good working order. In order to cure the problem I am having to fit new pads when there is loads of life left in the old ones. Surely one advantage of hydraulic braking systems is that any wear is automatically compensated for as the pistons move further out ? To be clear, I'm not talking about spongy brakes caused by air in the system. I just don't get it . Is this a characteristic of multi piston calipers ? What's the science here ?

Because you probably have tokico calipers and they are shite!

More than likely corrosion behind the seals causing the seals to grip the pistons and not slide easily resulting in the seals pulling the pistons back to their start point

To reduce the brake lever travel as the pads wear surely you would need a tad more brake fluid in the system to compensate for the extra travel required?

If that makes any sense???

To reduce the brake lever travel as the pads wear surely you would need a tad more brake fluid in the system to compensate for the extra travel required?

If that makes any sense???

No

As the pads wear the pistons in the calipers move further out

The fluid in the reservoir fills that extra space left by the pistons so you don't have to pull the lever more so you have the same lever movement throughout the life of the pads

The fluid may look low in the reservoir but only top up if you are sure it needs it and not that you need new pads as when you fit new pads you push the pistons back which then pushes fluid back in to the reservoir...if you have topped it up it can overflow

Thinks of it like an expansion tank on a car/bikes cooling system

Because you probably have tokico calipers and they are shite!

More than likely corrosion behind the seals causing the seals to grip the pistons and not slide easily resulting in the seals pulling the pistons back to their start point

Yep , Tokico calipers on both bikes. I've just read a lot of very similar posts on other Suzuki sites . Seals gripping the pistons and pulling the pistons too far back is looking like the best theory by far at the moment BUT not one practical solution to be found so far. Another suggested cause is warped disks that are effectively knocking the pistons too far back in. So I've got to check for run out when I get the chance. I guess a caliper seal kit is on the shopping list. Thanks for the responses so far.

To reduce the brake lever travel as the pads wear surely you would need a tad more brake fluid in the system to compensate for the extra travel required?

If that makes any sense???

Sorry, no . That's exactly what the reservoir is there to do. Thanks anyway.

Because you probably have tokico calipers and they are shite!

More than likely corrosion behind the seals causing the seals to grip the pistons and not slide easily resulting in the seals pulling the pistons back to their start point

Yep , Tokico calipers on both bikes. I've just read a lot of very similar posts on other Suzuki sites . Seals gripping the pistons and pulling the pistons too far back is looking like the best theory by far at the moment BUT not one practical solution to be found so far. Another suggested cause is warped disks that are effectively knocking the pistons too far back in. So I've got to check for run out when I get the chance. I guess a caliper seal kit is on the shopping list. Thanks for the responses so far.

The best solution by far is to replace them with nissin calipers

resealing works for a while but it will happen again eventually

you need to clean the groves where the seals sit really well a dremmel with a brass wire brush works well

If it was warped disks causing it to be that bad you would feel it when braking also when stationary you would be able to pump the brake up solid then you would feel the disk catch on the first turn

I was getting to the point of the brake lever getting too close to the bars........but I removed the pads and pumped the pistons out a bit, cleaned them up and smeared a bit of red rubber grease around the pistons......I then worked the brake until all 4 pistons moved together and I could push them back in by hand.......did this on both front calipers and then put the pads back in........front brake is spot on again......very little lever movement and nice sharp braking......

Ok, thanks for everyone's suggestions. I'll try a thorough clean up first although I do regularly give them a clean. I'll consider a seal replacement if that doesn't do the trick and I'll keep an eye on eBay for some Nissin calipers. What bikes use the appropriate Nissin calipers ? It's six pots on my current GSXR but four pots would probably be just as good .

measure the centres of the mounting bolts if they are 90mm you want them off an early bandit 1200 some triumphs rf900 theres is a long list I have posted it on here before

measure the centres of the mounting bolts if they are 90mm you want them off an early bandit 1200 some triumphs rf900 theres is a long list I have posted it on here before

These look promising http://i.imgur.com/ENrIzz0.png

Those are the ones

Have you measured the disk thickness ?

Have you measured the disk thickness ?

Haven't measured it but they are in good condition and not ridged . I've read a good few posts on other forums and the upgrade from Tokico to Nissin seems to be a very popular choice giving great results.

Have you measured the disk thickness ?

Haven't measured it but they are in good condition and not ridged . I've read a good few posts on other forums and the upgrade from Tokico to Nissin seems to be a very popular choice giving great results.

Bob I did this upgrade on my Ninja - totally recommend it.

Had the same problem with my ER6 over the last week or so. Took calipers off today and pumping the pistons out dragged out the dust seals so it was obviously those pulling the pistons back in. New seals on order but this is the second time. I had the same trouble at the end of last winter due to the crud getting underneath the seals. Tokico's again.

Hoggs also knows all about sticking calipers!

I have just rebuilt a rear caliper for her

Funny enough that was a tokico!

yes and hoggs changed her front calipers to nissin 4 pots after the wonderful Stu wouldn't shut up about how rubbish the tokico ones are

My Suzuki has Brembo callipers on the front. Tested them in an emergency braking situation and by God they are good.

I imagine the nissins will be fantastic too.

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Thanks again for your contributions , just done a full caliper strip and rebuild. Removed a lot of mineralization from behind the outer dust seals but I was pleased to find that there was nothing lurking behind the main seals. Reassembled,filled and bled the system and lever movement is right back where it should be. Result! Just hope it lasts. I'll see how it goes but I'm definitely going to upgrade to Nissins when time and budget permits. Thanks.

I was getting to the point of the brake lever getting too close to the bars........but I removed the pads and pumped the pistons out a bit, cleaned them up and smeared a bit of red rubber grease around the pistons......I then worked the brake until all 4 pistons moved together and I could push them back in by hand.......did this on both front calipers and then put the pads back in........front brake is spot on again......very little lever movement and nice sharp braking......

Yeah but I bet there's still a load of crap behind your seals . I was very surprised at the amount I discovered. Luckily it was only behind the dust seals . Just lubing the pistons treats the symptoms not the cause.

Just been for a ride, wow ! I've got brakes .

Glad you got it sorted. My new seals arrived yesterday so will hopefully get mine back together lster today.

Glad you got it sorted. My new seals arrived yesterday so will hopefully get mine back together lster today.

A few tips I'd like to pass on. "crack" all the bolts while the calipers are still on the bike,pump the pistons out by removing the pads while still on the bike as the disk will stop them coming right out. If the pistons still need pulling use a piece of rubber inner tube to grip them with pliers avoiding damage.( assuming you have split the calipers) Lastly I refilled the system very quickly with nothing but a metre of pvc tube. Just attach to each bleed nipple ,open and suck while continually topping up the reservoir. Best of luck.

I was getting to the point of the brake lever getting too close to the bars........but I removed the pads and pumped the pistons out a bit, cleaned them up and smeared a bit of red rubber grease around the pistons......I then worked the brake until all 4 pistons moved together and I could push them back in by hand.......did this on both front calipers and then put the pads back in........front brake is spot on again......very little lever movement and nice sharp braking......

Yeah but I bet there's still a load of crap behind your seals . I was very surprised at the amount I discovered. Luckily it was only behind the dust seals . Just lubing the pistons treats the symptoms not the cause.

They're ok at the moment......but I think it's due a fluid change next winter.....so I'll strip the calipers then and clean/replace the seals then......

Glad you've got it sorted.....