Rear brake pedal adjustment ?

[rkildu]

Can anyone clarify the proper technique for adjusting the rear brake pedal properly?

I ran across this thread on the K1100OG forum:

http://k11og.org/forum/viewtopic.php?t=10947

After reading it and the Factory Repair Manual (page 34.30) I am still confused about the adjustment on the master cylinder (number 3 on the diagram).  I am still fighting a rear brake light issue and am wondering if this is related to it.

Rod
97 K1100LT

[mystic red]

I don't think the adjustment will fix your brake light issue. If you do adjust, do so with care, as I almost burnt mine to the ground doing it wrong. :nono
You can't adjust pedal height which is what I was trying to do.

[CrashBar]

I spent 10 minutes on the side of the mass turnpike trying to blow out the flames coming off the rubber boot on the final drive.   I thought for sure (as I was choking on the burned rubber fumes I inhaled) it was going up in flames.     Learned my lesson, don't take all the slack out of the system.  Oh yea, and stick a little fire extinguisher in your saddlebag :lol:

[rkildu]

Yes,  that's one thing I'm trying to avoid.  But, I still don't understand that adjustment procedure. The description is a bit cryptic and short,  or I'm just a dumbass.

I have played with the adjusting bolt on the pedal trying to get the brake light to go out, so I have to get it back to spec.  If I understand everything I have read:

I need to adjust some slack in the master cylinder adjustment.

Then adjust the pedal bolt to get the 0.2 mm clearance with the feeler gauge.

And leaving the feeler gauge in place, adjust the master cylinder adjuster screw until I feel it start to engage, then lock everything down and remove the feeler gauge.

All of this should leave me 0.2 mm of pedal movement slack until the brakes start to brake.

Am I getting warm?  Correct me if I am wrong all you mechanical GURU's

Rod

[DRxBMW]

I spent 10 minutes on the side of the mass turnpike trying to blow out the flames coming off the rubber boot on the final drive.   I thought for sure (as I was choking on the burned rubber fumes I inhaled) it was going up in flames.     Learned my lesson, don't take all the slack out of the system.  Oh yea, and stick a little fire extinguisher in your saddlebag :lol:

he he, willing to bet that was a leaning curve on your part.

I saw a newbie jury rig an external fuel filter to the fuel rail hose once, with worm clamps to boot. He was clueless that the FF was inside the tank. Not a good move to have a FF or clamp failure around a HOT engine.

Shook my head in disbelief upon his arrival at the garage. Fuel lines were semi cut from the pressure spikes, friggin disaster waiting to happen.

There's a reason the FF is inside the tank. Fire in the crotch scenario can be a VERY exciting ride.

[frankenduck]

FWIW:  There's also a little rotational play in how the brake switch mounts. I always rotate my brake switches up as far as possible and leave a little play in the system.  The reason is that if I'm engine braking with a car behind me I'll also tap the rear brake lever not enough to engage the rear master but enough to light up the brake light to warn the person behind me that I'm slowing.

As Mystic Rod and Crashbar have warned, if you overadjust the brake lever and really apply the brakes then the rear master piston can get stuck on it's retaining screw, more or less lock the brakes and overheat the rotor to the point where the rotor heat will ignite the final drive rubber boot.

And if some dunmbass test riding your your bike just keeps riding with the brake locked up to the point where he lights it on fire and you're behind him when he finally pulls over, don't get so overconcerned with fighting the fire with one hand that you put your other hand on the hot exhaust.  It will burn the ch1t out of your hand and REALLY f'n hurts.  (I'm surprised that I still have fingerprints on that hand.)

[rkildu]

This thread had me concerned since I had replaced my master cylinder a while back and was having problems with the brake light staying on.  So I studied the diagram and instructions in the manual and headed to the garage to check things out.

After going through the process and checking the results I have concluded the intent is to make sure that the brake light comes on at the proper time and to make sure that the brakes are not rubbing when the pedal is not depressed.

The process assures that you have a minimum of 0.2mm travel, measured at the pedal stop,  to provide that clearance.

After some consideration I decided that this is too close. I wanted more pedal travel than that, so I backed out the master cylinder adjuster to give me about 2.5 mm at the pedal stop.  This allows me to tap the pedal and flash the brake light without engaging the brake but still gives me a pretty fast brake engagement.

The important thing is to make sure that the brake isn't dragging when the pedal is released.

Anyway,  that's my take on it.

Rod