Flexing calipers = soft lever?

[hampshirehog]

There was a dealer recall to put inserts in the caliper holders in, I thought, 1982 or '83, to stop this sloppiness. The inserts were like top hats and made out of very thin material, a tinny steel of some sort, that just pushed in. We got boxes of them where I worked expecting a rush but hardly anyone came in for the recall. If I also remember correctly this was a Heron UK recall and not a Suzuki one - no part number for the inserts and they didn't come in Suzuki boxes.

This subject has come up before and I know I've got a 'borrowed' box of maybe 100 inserts somewhere at my parent's house but I haven't found them yet. If I do come across them they're free to anyone who wants some.

In the meantime you could just make up some cylinder inserts using the lid of a baccy tin, which is about the same thickness.

[joshi]

so, what's the best solution?

I found this thread after experiencing an identical problem with my 1981 gs750E. Brand new MC and brake lines and rebuilt calipers and the brakes are still soft.

I though it was a bleeding problem but I compressed the calipers with c clamps and got a really nice feel to the lever. When I put them back on the rotors they were soft again. If I squeeze hard I can pull the lever all the way to the bar!

I can see the calipers move a little when I hit the lever and there's definitely some play in the axels. Is this the problem or do I have worn rotors? Did any of the suggested fixes solve this problem? What's the average life for brake rotors on these? Mine have a little over 30k on them.

thanks

[bwringer]

I have 112,000 hard miles on my GS850's brakes, and they're not sloppy like this. With stainless lines, they're verrrrry firm and nice, actually. Fantastic brakes for a vintage bike.

So no, this isn't normal and they shouldn't wear out like this.

To the OP: can you post a few photos of your braking system? As close as you can get.


Also, I've seen crappy aftermarket (K&L) rebuild kits cause something like this. The seals are built wrong, so they pull the piston back into the caliper a bit too far, and then you get too much lever travel.

You see, one role of the piston seal is to retract the piston just a tiny, tiny bit when you let off the brakes so that the pads aren't in hard contact with the rotor. A microscopic bit of elastic rebound is all you need, but shoddy aftermarket seals aren't made very precisely and sometimes rebound too far. The distances involved are nearly microscopic, but obviously very important.

Get OEM kits from your favorite Genuine Suzuki parts dealer. You'll find they're usually cheaper than the K&L Krap Kits, they include new pistons, and of course, they actually, you know, work right.

[Nessism]

I have also seen what Brian references. K&L brake parts suck.

One trick that sometimes works is to pull the brake lever back as far as you can and lash it tight with a bungie cord or similar. The caliper piston will creep out under load (sometimes). I've both seen it work, and not. Worth a try anyway.

[joshi]

Thanks for the replies guys! I love this site!

I tried lashing the brake lever back overnight but no luck with that. I did use an after market brake kit but I can't remember what brand. I may have to look into re-rebuilding the calipers. Bummer.

Where can I get a good rebuild kit? Any tips on cleaning out the cylinder bore? I remember it was tough to get all the crap out of the piston seal groove.

[joshi]

some photos

[850GT_Rider]

In the meantime you could just make up some cylinder inserts using the lid of a baccy tin, which is about the same thickness.

In English please?

[Suzuki_Don]

In English please?

That is English as opposed to American -- TOBACCO TIN

[850GT_Rider]

That is English as opposed to American -- TOBACCO TIN

UK, Australia, America.....3 countries separated by a common language.

[bwringer]

Thanks for the replies guys! I love this site!

I tried lashing the brake lever back overnight but no luck with that. I did use an after market brake kit but I can't remember what brand. I may have to look into re-rebuilding the calipers. Bummer.

Where can I get a good rebuild kit? Any tips on cleaning out the cylinder bore? I remember it was tough to get all the crap out of the piston seal groove.

Order the rebuild kit from your favorite source for genuine Suzuki parts, whether that's your local dealer, http://partshark.com , or whatever. OEM kits will come with high-quality seals and new pistons, and they're usually about the same cost or slightly less expensive than the aftermarket kits that don't contain new pistons.

You have to get the cylinder bore perfectly clean and clean up any pitting with emery cloth. You don't need a brightly polished finish, but it must be very smooth.

Use a pointed wooden or plastic stick or a pencil to scrape out the grooves. Sometimes you have to use a metal pick on stubborn bits, but VERY carefully, and VERY lightly.

[jimfj]

JOSHI...where di you get the adjustable levers that I see on your GS????

I would like to have a set of those.!!!

I have the same problem everybody that has posted here has. I have a full stainless setup with good seals and pistons. pads are good. The stainless lines helped a grea deal, wont have another bike without them. My lever is sloppy until the pads start to touch the rotors and them they firm up nicely. stops well but i don't think I should have the travel I have and after a while it seems to get worse and I have to reset everything.

i am in interested in the recall shims or whatever they are called. Mine is an 82 GS1100G so I believe that fit the time period mentioned earlier.

Jim

[Macmatic]

Hi, long time, no posty.

I've been away from a lot of things since last Fall but I did manage to get my caliper rebushing project done and tested. I actually just got back from the Bennington, VT Triumph Bash which was an 800mi weekend. Didn't get to bash any Triumphs but I did smoke a Thruxton or two...

The bushing mod made a big difference but I'm still getting a little flex in the calipers but I'm pretty convinced this is just inherent in the design at this point. Maybe. I'm getting some minor squish with the beefiest C clamps I have holding the pistons in the bores but I'm also seeing noticeable flex in the clamps.
When installed with the old carriers and rubber bushing I had better feel after switching to a full SS line system, I'm running 3 and had a rubber MC to splitter hose until last week. Once I installed the rebushed carriers and new rubber bushings on the small pins I had better lever feel still and the new pads I threw in are getting even wear as opposed to the noticeably uneven wear with the old setup. Caliper rock is reduced but not gone, however it is too small to see when pulling the MC lever. Before this mod you could see the calipers rock every time you applied pressure. A clicking noise under low speed, light pressure braking that I'd been trying to dope out is also gone. I think it may have been the calipers rocking and clicking the sloppy pin bores.

I'll be doing a new set with a slightly smaller bore for the small pin. I'm going to try the first ID I tried which I later increased slightly because the rubber pin bushing was binding. It turns out that those rubber bushings got lubed with something they didn't like and swelled up so my first bore size choice may have actually been right. The first test with these seemed like it had a firmer lever but I can't really say since I had a rubber line at the time and it was a couple of months ago now.

So in the end, or at least near it, I'm pretty happy with how this turned out. No magic bullet but the braking power, lever feel and pad wear are all improved. I'm sure I'll still upgrade to twinpots or some other calipers in the future but for now this is a good compromise.

I'm sending a set to the member who sent me some spares to test with once we make arrangements so I'll ask him to post his impressions here once he gets the new carriers on. I'll also be posting pics as soon as I remember the password for my flickr account...

Here is my brake setup info.
Freshly rebuilt 'busa 5/8 MC, bench bled and then pressure bled with the whole system.
Stainless lines
No anti-dive connected
New rubber bushings on the smaller pins
Newly rebushed caliper carriers.
New ELCHEPOH Pads, soon to be replaced with HH sintered pads. I'll be posting a review on those after I get 1000mi or so on them. My rotors seem to be stainless and are hard as...hard so I'm not expecting too much wear from the sintered pads...I'll be measuring though. If nothing else they may be a "resurface while you ride" option.


The /\/\ac is back.

[kingofvenus]

I had a set of '83 750 calipers and rotors on my 850. Last year i did the complete twinpot mod, they are so much better than what i had on there before, they are almost as good as the 320mm rotor 4 piston RF900 brakes that are on my 750. And they're cheap to buy. Do your self a favor and get a set of the brackets from Salty Monk while he still has a set, you can always get the other parts later...

[Macmatic]

I had a set of '83 750 calipers and rotors on my 850. Last year i did the complete twinpot mod, they are so much better than what i had on there before, they are almost as good as the 320mm rotor 4 piston RF900 brakes that are on my 750. And they're cheap to buy. Do your self a favor and get a set of the brackets from Salty Monk while he still has a set, you can always get the other parts later...

Bah! You and your fancy new parts...