How much travel at your front brake lever?

[bwringer]

A few more thoughts...

What sort of bike do you have? I'm trying to picture which braking system it is. IIRC, most or all of the 80-85 GS bikes used the same brake system, so we would have directly comparable results. With stainless lines, you should get no more than 16-21mm of lever travel. Period.

You can't really compare lever travel with modern 4 and 6 piston calipers and different master cylinders. Apples to oranges. The amount of force you'd apply to stop a GS moderately would be enough to lock the wheel and send you into the weeds on a modern sportbike. They need more level travel to give you the needed degree of feel fine control, so the master cylinders are sized differently.

On a GS, the single-piston calipers and relatively large master cylinder diameters mean that you have to give the lever a manly squeeze to get good stopping, and that it's not going to move very far between "whoa" and "OH %$#@!!!!".

 

[bwringer]

And to answer at least reply, the pads are in very good condition and they only go in at one position.
The piston/cup set is only a couple years old too. If it has a problem, it would only be the possibility the cleaner compromised the rubber cup and how it slides smoothly. There's absolutely no leak at the bore from a damaged rubber cup.

You're not getting any leaking and the lever doesn't sink under constant pressure (at least not that you've mentioned), so I agree that the seals aren't the problem.

 

[KEITH KRAUSE]

OK. To answer a few more.
The old seals were swelled and the pistons were both sticking out noticably when I took off the calipers. New genuine Suzuki seals fixed that. The pistons move correctly.
The lever travel doesn't decrease if I pump it. The lever doesn't get any harder.
I did see air bubbles escaping out of the smaller return hole (under the reservoir bottom). After some time, but not before the bleed was completed, the air bubbles completely disappeared from the hole. I did clean and blow this return hole out, without seeing any blockage, about a year ago. I don't completely doubt that a very small amount of silicone could still remain and I'll deal with that if I can't get a fix another way.
I agree it seems like a return problem, but with the return hole clear and the pistons now retracting correctly, I can't see how it's happening.
The silicone residue remains a possibility and I admit I don't fully understand how only a film of silicone, if that much remains, could cause a travel problem. There's no way a glob or large amount of silicone remains.

 

[KEITH KRAUSE]

Sorry if my replies are a little behind your replies. I take a long time to think what I'm typing.
My bike is a '79 GS1000E. Single piston calipers. Dual rotors. SS lines.
I agree it's hard to compare different models and it's also difficult to explain just how much travel I'm getting and what kind of lever force is being used. I'm just trying to get some idea to compare. I think something's wrong but what's confusing things is how you guys have even less travel than me BEFORE I replaced the seals. I had 1" and I KNOW for a fact that it was too little, based on what the bike had awhile back when there was no problem. As the dragging/sticking got worse, the lever travel decreased to 1". Before the problem, I can't say how much the travel was because I never would think to measue lever travel. But the lever travel was noticably more than 1" and my brakes worked perfectly.

 

[KEITH KRAUSE]

Bruce, old buddy. If you have no brake problems, could you give a measurement please?
Also, anyone, the levers I've used for many years are the "dog-legged" levers. They make it easier to reach the lever. They certainly aren't the problem but because they are closer to the grip, they are making my "excessive" travel problem more noticable. Stock levers would help somewhat in that the lever wouldn't come as close to the grip. The travel wouldn't seem as excessive then.
I wonder what the difference is from the stock levers and the dog legged style? If anyone can show a pic of the stockers next to the typical dog legged style or just measure how much "further out" the stockers would be, I'd really appreciate it. If I can't fix my problem, stock levers would help minimize the problem.

 

[Guest]

Bruce, old buddy. If you have no brake problems, could you give a measurement please?
Also, anyone, the levers I've used for many years are the "dog-legged" levers. They make it easier to reach the lever. They certainly aren't the problem but because they are closer to the grip, they are making my "excessive" travel problem more noticable. Stock levers would help somewhat in that the lever wouldn't come as close to the grip. The travel wouldn't seem as excessive then.
I wonder what the difference is from the stock levers and the dog legged style? If anyone can show a pic of the stockers next to the typical dog legged style or just measure how much "further out" the stockers would be, I'd really appreciate it. If I can't fix my problem, stock levers would help minimize the problem.

Hey, Keith,
I just finished installing my SS lines, but have not yet bled the lines. I will get that done later today and post my results for you. I had no brake problems prior to putting the new lines and new pads on.

 

[Guest]

I'm getting 1 3/4" travel from the end of the handle, which feels about the same as I was getting before the SS lines. But boy, what a difference the braking performance is!

 

[Guest]

Oh, and the very end of my brake handle is exactly 4 inches from the start of the grip (inside to inside).

 

[Rocketman]

Thankfully, the one problem I haven't had (yet!!!) with my '82 GS850L is braking, However, I just measured 3/4" end ball travel to moderate braking, 1" to full pulled in brake handle. That's with broken in pads and SS lines. Hope that helps.

 

[KEITH KRAUSE]

Thanks for the replies.
Bruce, all the way out, my dog legged lever is only about 3 1/4" from the grip, so when I pull in my lever it now comes to about 1 1/2" of my grip...just doesn't feel right. I'm assuming your lever that is 4" out is stock??? A lever that is 4" out would certainly help this situation, though it's not the levers fault. When I pull in the lever now with two fingers, the lever starts to touch my fingers remaining on the grip, especially with my glove on.
Anyway, I believe I've figured out the problem and I'll post it in a bit for those interested.

 

[KEITH KRAUSE]

Thanks very much for the replies. I believe I've found the actual problem and would like to share it with those interested. Being a safety issue, I take it seriously and feel I should share what I think the problem is. Pardon how detailed I get and the long read, you guys know me by now.
To recap a bit... my brake lever travel was slowly getting less and less and the brakes started dragging some. I'm guessing the original pre-problem travel was about 1 1/2". It was now at 1" and no longer acceptable.
A local bike shop suggested the silicone fluid I ran had swelled the piston seals and with the pistons no longer retracting correctly, they dragged and created my "hard lever". The shop was correct as I replaced the seals and thoroughly disassembled/flushed the silicone out and the problem was gone. The pistons could now be pushed back with finger force, where before they were stuck solid. After re-assembly, I could feel the small amount of play that both caliper assemblies should have when the lever is released. There was zero play before at both calipers. I'm positive the new seals had fixed things. I bled the brakes by hand and with a pump and ALL air was positively removed.
However, now I had the opposite problem. There is excessive lever travel now. 1 3/4". This actually is close to many new bikes I tested at the local dealer but I knew it wasn't right. I re-bled/flushed and couldn't figure out what was going on (as some of you have read)...until now.
Sometimes fixing something can expose a second problem. In my case, it seemed the only problem was swelled seals. Wrong.
After all the bleeding, etc, I noticed the play at the left caliper had lessened as compared to the right caliper. There was no doubt the left caliper was now a little tighter against the rotor. When released, you could see a gap between pad and rotor on the right, but not at the left. Wiggling the caliper body by hand also made it obvious that the left had lost some play and was no longer equal to the right. Hmmm. Now the earlier signs during disassembly made it obvious. There was a small leak from the seal that couldn't be seen until the caliper was upside down in my hand. It also required 100 PSI to blow out that piston (only 35 for the right side). There was also a very small "shiny spot" in the bore where the piston, barely changing position, rubbed. I could not feel this spot with my finger, I could only see it so I thought it was OK.
It now seems obvious that I also have a cocked/semi-sticking piston. The piston isn't moving straight in and out as it should, thus the shiny mark in the bore. The cocked piston would tend to make the seal leak prematurely too. With the left piston now sticking out a little more than the right side, I have less play at the left pad and rotor. This is why the excessive travel I believe.
Since I have two calipers, as the lever is pulled in, the left side contacts before the right side now. With the right side "lagging" behind the left side now, there's no way you're going to get a solid feel at the lever until both calipers are contacting reasonably hard. They MUST operate equally. After the left contacts well, the right still needs more fluid/lever pull to contact solidly. Thus the extra travel/pull needed. Makes sense to me.
Now my problem is I need a replacement caliper body. I have no faith in trying to sand/polish, etc, the bore in an attempt to make the piston move correctly. The factory manual says the service/wear limit of the piston or bore is only .001" from new. Any attempt at re-surfacing the bore would surely take me out of spec. So now I have to try to find an NOS caliper if I can, or play the used part game. The caliper is no longer available at the dealer.
Thanks for reading this and let me know of any thoughts you have.

 

[KEITH KRAUSE]

Just bumping this up.
I made the last reply late last night and I know how soon it can get buried in the tech section. I'm off to work now but would like to read any thoughts you may have.

 

[rustybronco]

It hasn't been forgotten i will post my (unqualifed) thoughts later when time permits.
EDIT...
A few things to think about, the less distance between the caliper piston and pads to the rotor the less lever travel required to apply the brakes, to correct a longer travel you would have to reduce the clearance between the piston-pad assembly and the rotor to the point just before they begin to drag to be at the optimum distance, also the pads must be parallel to the rotor or they will have to be "twisted" parallel to the rotor by more fluid requiring greater lever travel. does it seem safe enough to ride to let the pads seat in and see what happens to the lever travel?
the seals in the caliper bore retract the pistons that combined with lateral rotor movement (a slight wobble if you will), have you checked the run-out of the rotors to see if they're excessively warped because of the problem you had with your seals, causing the piston to be pushed back further into the caliper on the right than on the left side?
if the brakes do not drag on the left hand side i suspect the problem of excessive clearance or improper pad wear may be with the right side, if i have read your post correctly.
have you measured the clearance of the caliper and piston to see if it within spec?
what side has the shiney spot in the bore? i think it is or was caused by the pad not seating correctly or an incorrectyly aligned caliper causing a side load on the piston where as a correctly aligned caliper (in relation to the rotor) would not.
without moving the bike do the brakes pump up any?

 

[GregM.]

I SURE don't know the mechanics like you all do (I'm learning though, reading all this). I hate to admit that I just paid someone to change my brake fluid, how pathetic am I ....But, I can give you measurements. Seeing this for the first time today, don't know if you still want 'em... just trying to partcipate

1980 GS850G... No up-grades to the brake system (no S.S. lines) all original I think. Also, pretty sure my levers are stock... everything else seems to be. Don't know if you'd call them a dog-leg style or not. They are NOT a smooth, one arc shape from the pivot point to the ball-tip end. There IS a change of arc about 2 1/2" out from the pivot point... But I wouldn't call it a major dog-leg.

Distance from inside the ball-end of the lever to closest inside point on the stock grip is (at 90 degrees to the grip) 3 3/8". Then, walking forward, squeeze lever to induce a good stop, with front forks dipping ... the same distance is now 2".
Therefore, lever travel is 1 3/8".

With right hand on grip - 2nd and 3rd fingers resting on lever just inside that very subtle dog-leg - thumb and 4th and 5th fingers wrapped around lever... when I squeeze the front brake, the lever is not touching fingers 4 & 5. However, if I REALLY need the fronts on hard, I get fingers 4 & 5 on the lever too. Good luck and thanks for letting me read along

Edit: Here's a weird thing - now that you got me measuring... the same distance from ball to grip on front brake lever that is 3 3/8" (as said above) ---- On my clutch lever, is 4 1/8" !!! Why is my clutch lever sticking out 3/4" more than my brake lever? Or, why is my brake lever in 3/4" closer than my clutch lever? Shouldn't they be the same?

 

[rustybronco]

I SURE don't know the mechanics like you all do (I'm learning though, reading all this). I hate to admit that I just paid someone to change my brake fluid, how pathetic am I

pathetic? just give yourself some time in this forum...that will pass.

 

[rustybronco]

Just keeping the post warm for you Keith.

 

[KEITH KRAUSE]

Thanks for the replies. I had a long day but I thought I should reply since you guys were good enough to.
Greg, my levers measure differently too. I have about 3 1/4" I.D. from the brake lever ball to the grip and right at 4" at the clutch lever. Not due to any lay downs, etc. After looking at it, it looks to me like the outer edge of the bracket that the clutch lever mounts to actually points inward slightly (toward headlight). This completely changes the angle between the lever and grip. The lever apparently goes out/away more because of this.
Where the brake lever mounts on the reservoir/brake lever mount, that outer edge is straight in line with the bike, so the lever starts at an angle several degrees less. Hope I explained that well.
Rustybronco, I measured the piston and bore and they were right at the service limit which allows for only .001" wear. Actually, my calipers need to be re-calibrated because the needle is off by what looks like .0005". So I'm not positive but the shiny mark is not a good sign for sure. It proves things aren't going in and out straight enough. I forgot just what position the mark was at and the parts are back together for the moment.
The bike hasn't been off the centerstand. I think I can ride it but I don't like the lever play. I haven't measured rotor run out but there doesn't appear to be a problem there (simple spin test). The rotors thickness is within specs. The brake lever will not "pump up". The 1 3/4" travel is consistant after extensive bleedings. The pads are in good shape and don't look like they're wearing incorrectly, though I could measure them when I take things apart again.
The caliper axle bolts have a good chrome plating still and are re-greased with specific caliper axle grease and the o-rings they use were replaced recently.
There is obvious less play at the left caliper than the right. I feel the right is operating as it should. The pad should release the rotor, not by much, but it should. The right does that. The left isn't really dragging that much, but it's obviously not releasing the rotor and there appears to be constant contact. I'm no expert, but I can see it shouldn't be doing that.
So the calipers are not applying equal, or equal enough, pressure. I think the excessive lever travel is because the right side needs a bit more pressure to stop the lever because it has to "catch up" to the left side. I suppose it could always be something that I just don't have the experience to see, but I have to blame the piston and/or its bore. The previous clues during disassembly suggest the same thing. The leaky seal, the shiny spot, the piston was stuck MUCH tighter than the other. I think it's cocked a bit and after several compressions while bleeding/testing the feel, it would appear it's semi-sticking again. Not anything like it was before due to swelled seals, but the left caliper/piston is obviously out a bit more than the right.
I don't like spending $ any more than the next guy, but I probably won't deal with used calipers. Time is money and I'm looking at possibly buying an NOS caliper assembly. Looks like I found one for $200 and I'll do some more searching. Seems like if I buy the whole assembly, I have a great shot at getting rid of the problem. I just can't see what else it could be.
Thanks again for the help. Gotta get to bed.

 

[rustybronco]

There is obvious less play at the left caliper than the right. I feel the right is operating as it should. The pad should release the rotor, not by much, but it should. The right does that. The left isn't really dragging that much, but it's obviously not releasing the rotor and there appears to be constant contact. I'm no expert, but I can see it shouldn't be doing that.

I agree it should not be dragging

So the calipers are not applying equal, or equal enough, pressure. but I have to blame the piston and/or its bore. The previous clues during disassembly suggest the same thing. The leaky seal, the shiny spot, the piston was stuck MUCH tighter than the other. I think it's cocked a bit and after several compressions while bleeding/testing the feel, it would appear it's semi-sticking again.

the bore is possibly not round not allowing the piston to retract properly, and an inside mike would confirm?!? as you said time is money but inquiring minds would like to know.
one question i did ask that i may not have been clear on, is the shiney spot in the left or right caliper?
not where in the bore.
one more thing if the piston measures round possibly put some kind of grease, marking compound or what not to the area(s) in question and if there is a high spot, take crocus cloth to that area.

 

[KEITH KRAUSE]

Thanks for the reply. I'm off to work in a second.
The shiny spot is in the left caliper. The left seems to be the problem caliper and shows several signs. The right had no signs of problems during disassembly. I'm just not 100% sure why the left isn't acting like the right and I don't want to buy an expensive part to fix things. But I'm about 99% sure it's the piston or bore.
I'll measure things and let people know the results later when I can.
For the moment, unless a better idea pops up, I plan to test ride it and see what I think. I feel it's OK to ride. If anything, I feel the left side will just worsen regarding sticking. That would tend to lessen the brake travel if the past is any indication.

 

[KEITH KRAUSE]

Well, I bit the bullet and ordered an NOS caliper assembly from Australia.
I'm just glad I found one. $227 including shipping but that's actually a bit lower than the dealer cost 6 years ago which was the last I heard it was still available.
I have poor luck with used parts so I just didn't want to try it.
Anderson Vintage Parts did have one listed for $120 but he's on our deadbeat list. Jeez, he used to be a good guy.
To add to the caliper sticking piston/bore problem, it appears I've over-torqued the bleeder one too many times as it started leaking very slowly. I tightened it but no luck. It should only be torqued about 5 lb/ft. It's easy to over torque at that amount. Nothing you can do if you damage the spot where the screw tip seats. I blamed the Russell speedbleeder and bought some new ones but it turns out the bleed screw seat must be damaged. So I wasted a little more on that. Oh well, live and learn.
I'm just glad to have a new caliper on the way. At least the assembly comes with everything. Just the genuine Suzuki chromed caliper axle bolts go for about $27 each. And I get some new pads so I'll only need 1 set the next time too. I hope to get another 130,000 miles on this caliper.
I just told the wife I'll consider this my Christmas gift. Doesn't cost a thing if you look at it that way. At least this year I'm getting something I want, even if it's not a surprise.:lol:
Thanks for all the replies and I hope this thread helped others.