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Brake & Clutch Lever Freeplay (pre 2017 models)

75K views 144 replies 31 participants last post by  Dutch-T 
#1 ·
The (excessive) amount of front brake lever freeplay (travel) before the brake applies has been discussed a bunch so I looked at reducing it.

There's a limit to how much free travel you can remove. The master cylinder piston has to retract enough to open the bleed port in the master cylinder. Naturally BMW has placed a rubber "bellows" with a slit in it over the bleed port so you can't see the piston opening the port. The "bellows" is the round black thing in the bottom of the master cylinder reservoir, you have to remove the cylinder cap to see it.

With the cap removed, pull the brake lever and you'll see fluid move. This happens at the very beginning of your lever travel and what you see is kind of a "bulge" in the fluid. It will squirt fluid if the fluid level is low enough (or you pull the lever fast enough) so be carefull. This is fluid the piston is pushing out the bleed port before the piston closes the port.

Soo, if we adjust the "threaded goody" on the lever we can move the pistons' starting point so it closes the port sooner requiring less lever movement to close the port and start braking.

Lost you yet?

Now we adjust the "threaded goody". The one with plenty of red loctite on its' locking (grub?) screw that you've probably read about...

Fortunately acetone will dissolve the loctite. With the loctite dissolved the locking screw on mine loosened easily.

You adjust the "threaded goody" to make it longer to push the piston in more. Adjust and try. Get the front wheel off the ground. Rotate it by hand and see when the brake starts to apply. You have to still be able to see the "fluid bulge" in the reservoir. That means the piston is still opening the port. This is IMPORTANT.

I went 2 turns. At 2 1/2 turns I saw a decidedly reduced fluid "bulge" so I went back to 2 turns. I applied purple 222 Loctite to the locking screw.

There's less lever travel now before the brake applies.

This is also what you check after you install aftermarket levers and find your clutch is slipping. You have to adjust the "threaded goody" so the port is opening. That open port is what releases the line pressure in the system.

BE CAREFULL. IF THE PISTON ISN'T OPENING THE PORT YOUR BRAKE WON'T FULLY RELEASE AND THAT IS VERY BAD.

Same on the clutch side. If the piston doesn't retract far enough to open the port the clutch will slip.

Have fun...
 
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#2 ·
Now we adjust the "threaded goody". The one with plenty of red loctite on its' locking (grub?) screw that you've probably read about...

Fortunately acetone will dissolve the loctite. With the loctite dissolved the locking screw on mine loosened easily.
Heck, man! Where were you when I was hauling on my grub screw???? OOOPS that almost sounded rude! 0:)

Good tip about using acetone! I'll remember that next time!
 
#4 ·
Gotta be carefull, you're girlfriend might feel left out...

Acetone is the usual primer for "real" Loctite if you want best performance and does to an extent dissolve it. I wasn't sure how it would work on what BMW uses but it pretty much instantly turned it to goo and freed up the screw.
 
#12 ·
BTW: See how there MUST be some room in the MC reservoir for the extra fluid to go there? Guess what happens if overzealous person with best intentions fills that reservoir all the way to the very top? Where does that extra fluid go when lever is squeezed? That is correct - leaks out through the top.
 
#17 ·
If you want minimal free travel you adjust 'til the port isn't open and go back. Problem is it's hidden so you can't see this happening and can only see the "bulge" in the reservoir fluid from fluid coming out the open port at the very beginning of the lever travel. You're the one that's there to see it on your bike.
 
#18 ·
Gentlemen, help an old sailor out here. I looked at my brake assembly and what I saw was the "goody" piece with what looks like a 2.0 or 2.5 hex bolt in the end. What I saw underneath was a "red" dot. I'm assuming that that is the dreaded loctited bolt. If what I just said makes sense then all I need to do is remove the loctite and turn the adjusting screw accordingly.
 
#24 ·
I'm not speaking for @tomcatt as he's fine in that department (hehe - no offence mate) but some things like the bulge in the brake fluid would be difficult to photograph.

Here's a picture of the "threaded goody" that tomcatt mentioned. You can see the cylindrical pivot that the goody screws through. On the bottom of it is where the threaded grub screw is.....



If you are nervous about doing this adjustment my advice would be to take it to a dealer and let a mechanic do the work for you. No point in playing with your safety and the safety of other road users if you are not confident in doing the job right.....

Being a home mechanic is great but we all have to be aware of our limitations... Some of the stuff on here that I've seen other members tackle with aparent ease I'd be picking up the phone and calling for someone that's way more competent than I to do the work for me! lol :)

PS What the heck is a goody anyway????? That slang for a "thingy" or is it another name for a pushrod/adjuster?
 
#28 ·
Its just a small hex-headed screw that is buried into the lever assembly and prevents Pushrod thingie from getting loose. Seems like its universally over liberally coated with Red Thread locker. (Interesting that its the issue only on ONE lever not both. Sigurd must be experienced and Franz must be new)

I personally, used a dentist type pick to remove excess from the inside the screw itself and around it. I had so much that bit would not even insert in. But once i cleaned it up i was able to put it all the way and used ratchet to crack it open.

This should be really not an issue for anyone. Truly. Just a tiny little obstacle
 
#29 ·
Yep I did the same. I used a small dubbing needle (fly tying don't ask) after applying some acetone to clear the head of the grub screw of gooey thread lock and after that it was a piece of cake with a T8. Brill help and support from the forum as usual and big shout for Acetone, it's my favourite accessory don't you know.
 
#32 ·
Once you've had a play on either or both levers I'd suggest going for a ride with your T8 handily (and safely stowed) because I needed to adjust mine back a turn on the clutch side after riding for 15 miles in a 'spirited fashion' it looked ok on the stand in terms of clutch bite point but was different once the engine was warm. Definitely makes the braking more responsive (less lag) and maybe a tad smoothy going into bends on the overrun.
Once you're happy of course you need to thread lock that grubby little screw ?
Marky Mark
 
#40 ·
Mark has pretty-much did what I did. Test rode the bike after getting the settings roughly right and then fine tuned the setup from there. The clutch needed no adjustment at all even after really nailing the throttle when the engine had fully warmed up. The brake side needed a full turn in to take up slightly too much slack before the brakes started to bite. It's no big hassle to take a small allen key with you to do the final setup on the road.

Brakes definitely seem better than they were previously. Possibly placebo in some ways, but the lack of lever travel before the brakes bite compared to before does make the anchors seem more responsive and less snatchy. However the shorter levers may have something to do with the snatchiness reducing as well - hard to say as both modifications took place at the same time.

Now where did I put the loctite?????
 
#37 ·
Whyara,

Dave's picture on page 3/4 of this thread shows the threaded area. Zoom in on it and you'll see the threads clearly. I can't stress what other people have said, take care with this work especially on the brake side and check the bite point by rotating the front wheel before you ride.

25psi, I was joshing a bit as my colleagues say my default setting is grumpy. I'm enjoying the bike more with each ride and the tinkering that it takes...just need to get that bar changed and fork internals sorted.

Mark
 
#39 ·
Dave's picture on page 3/4 of this thread shows the threaded area. Zoom in on it and you'll see the threads clearly.
But when the lever is mounted, you cannot see the threads clearly.

I can't stress what other people have said, take care with this work especially on the brake side and check the bite point by rotating the front wheel before you ride.
For sure I checked the bite point on the brake side with a center stand and everything works fine - but I'm a little bit afraid of that I pushed the master cylinder to much to the inside and it won't open ?

Next day's the weather forecast is good and I will go for a extensively testride (with the needed tools in my bag) !
 
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