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1Back to top Go down   4-pot front caliper siezed Empty 4-pot front caliper siezed Tue Jan 14, 2014 6:12 pm

SteveK1

SteveK1
Silver member
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Working through an old "basement-find" K1 with low-ish miles and weird EFI problems. So, figured out a work-around for the EFI, load shed problem (see earlier thread from September under electrics, still waiting on the german CD containg K-1 specific diagrams for EFI wiring).  Went through much of the bike, fuel-pump, rail, valve adjust, etc. Radiator, pump, fan. Fluids replaced, rebuilt and honed front master (replaced piston and seals, but really the only problem seen once apart was a missing copper-washer on the adjustment screw), bled front and rear brakes. Battery in and out working on systems, so ABS is disabled, not reset...  I'm out for a spin on a nice day to see what she can do.  Hard on brakes at a traffic light, accelerating away nicely, hold-on, what's this, feels like I'm loosing power having to apply more throttle to maintain 60 mph... No, I quickly realize, I'm in the middle of a busy highway and my front caliper is rapidly siezing, the more heat, the more siezed.  Quick pull off and out of traffic. Just as I'm pulling into a safe parking spot, the front locks-up and now I need paint and to repair the shifter lever (busted my watch too, damn-it).  Any-way, several (five) hours later, the front brakes cooled and rode her home, careful not to touch the front brake, no binding seen in parking lot or once home.  Question: does this seem like a master problem (both discs were super-hot) or a caliper problem?  Should I rebuild the caliper? should I just replace the lines and flush the system?  And, please, in retrospect there are obvious precautions not taken, so please don't tell me why I am a dumb-ass, likely someone already did.  Thanks, I obviously value your insight! ;BMW;



Last edited by SteveK1 on Tue Jan 14, 2014 6:20 pm; edited 1 time in total (Reason for editing : confusion)

    

2Back to top Go down   4-pot front caliper siezed Empty Re: 4-pot front caliper siezed Tue Jan 14, 2014 6:30 pm

rosskko

rosskko
VIP
VIP
Sounds like minimal damage to you and the bike. In my experience you were lucky to get off the road.
Master cylinder is my answer.

Tiny weeenie almost invisible hole in master cylinder that lets fluid leak back into the reservoir and release pressure from calipers.

If it were to happen again, relieve pressure via bleed nipple and all good to go again (while staying off the front brake).

Ultrasonic bath my get the dirt out.

Never quite understood why they want the brake fluid to be ultra clean and wipe the lids of dirt before removal. If the hole is blocked then this is the reason.

4-pot front caliper siezed Mccut


__________________________________________________
1986 K100RT VIN 0093801K100RT with summer fairing for a northern visitor

Basic/2 6308802K100CJ  05/1988

K1100RS 0194321
    

3Back to top Go down   4-pot front caliper siezed Empty Re: 4-pot front caliper siezed Tue Jan 14, 2014 6:32 pm

Arlina

Arlina
Moderator
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Sounds familiar, been there done that...
Ok, it was a Jawa 640 Red Style, but same bugger.

Installed new pads, new brakefluid dot 5.1 , flesh it till the whole 250cc went through.
Bug fixed Smile


__________________________________________________
4-pot front caliper siezed Eu-log10  K1100RS/LT - R1200RT - R1100RS (RIP) - Cagiva SST 350 Ala Verde - K75LT project - K75 Schurgers - K75S
    

4Back to top Go down   4-pot front caliper siezed Empty Re: 4-pot front caliper siezed Tue Jan 14, 2014 6:45 pm

Guest

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"german CD containg K-1 specific diagrams for EFI wiring"

Is there a difference between the K1 and the K100RS 16valve? I thought that they were both the same apart from fairings. My Clymer manual has the supplement for the K1 and the K100RS.

    

5Back to top Go down   4-pot front caliper siezed Empty Re: 4-pot front caliper siezed Tue Jan 14, 2014 7:04 pm

RicK G

RicK G
admin
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If the adjustment screw is adjusted too far in the piston cant return far enough to relieve the pressure and the brakes will sieze on. There should be about 5mm of free travel at the end of the lever before the master cylinder starts moving the piston, this way you are sure the piston returns to the home position properly.

There is no difference between the K100RS 16v and a K1 EFI the Clymer manual covers all you need to know and more.


__________________________________________________
"Man sacrifices his health in order to make money.
Then he sacrifices money to recuperate his health.
And then he is so anxious about the future that he does not enjoy the present; the result being that he does not live in the present or the future; he lives as if he is never going to die, and then dies having never really lived."   Dalai Lama


Bikes 1998 K1100 LT, 1993 K75 RT, 1996 K75RT, 1986 K75 GS, 1979 Z1300 Kawasaki
    

6Back to top Go down   4-pot front caliper siezed Empty Re: 4-pot front caliper siezed Wed Jan 15, 2014 12:32 am

SteveK1

SteveK1
Silver member
Silver member
bikerboy wrote:"german CD containg K-1 specific diagrams for EFI wiring"

Is there a difference between the K1 and the K100RS 16valve? I thought that they were both the same apart from fairings. My Clymer manual has the supplement for the K1 and the K100RS.

Right, the K1 and the RS-16 valve are "essentially" the same, few minor wiring differences from what I understand. But the wiring diagrams in the Clymer are not particularly useful, hard to follow, black-n-white, confusing.  I was shown what I will be receiving (the LT version), with "pull-outs" pin-diagrams, shows where harnesses are located, and connect to other harnesses, in color, so on.  I figure for $35 bucks it might save me some frustration.  BMW of South-East Michigan tells me it finally arrived, I can come pick it up.  Need to schedule a trip out there.
It seems to me the EFI problem (discussed previous in electric thread) is a result of the PO moving an EFI ground wire somewhere to the load-shed circuit, but I would like to figure out where.  I can bypass the EFI shut-down by closing the load-shed relay...
As for the front brake binding up, I do suspect the return in the master was plugged.  Any experience with this?  If I flush with enough volume should I feel confident this might solve it, or should I dissemble everything and clean?



Last edited by SteveK1 on Wed Jan 15, 2014 12:44 am; edited 1 time in total

    

7Back to top Go down   4-pot front caliper siezed Empty Re: 4-pot front caliper siezed Wed Jan 15, 2014 12:35 am

SteveK1

SteveK1
Silver member
Silver member
@RicK G wrote:If the adjustment screw is adjusted too far in the piston cant return far enough to relieve the pressure and the brakes will sieze on. There should be about 5mm of free travel at the end of the lever before the master cylinder starts moving the piston, this way you are sure the piston returns to the home position properly.

There is no difference between the K100RS 16v and a K1 EFI the Clymer manual covers all you need to know and more.

Thanks Rick, seems like I did have that screw adjusted correctly, 5mm of free travel at end of lever.

    

8Back to top Go down   4-pot front caliper siezed Empty Re: 4-pot front caliper siezed Thu Jan 16, 2014 6:23 pm

SteveK1

SteveK1
Silver member
Silver member
Just found an old Thread, where Rossko was having a similar problem. 
https://www.k100-forum.com/t1301-brake-seizure
Read through it, and lots of good information there.

    

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