Front Breaks Not Working After Master Cylinder Rebuilt Kit

[85-K100-Cafe]

Hello everyone,


My front master cylinder was leaking so i installed the rebuilt kit. After bleeding the front brakes for about an hour i am not getting any pressure in the calipers. i manual bled the front brakes and it seem like i am not getting any fluid down to the calipers. Any suggestions? Bike is a 1985 K100RT with ABS. Thanks

[Laitch]

i manual bled the front brakes and it seem like i am not getting any fluid down to the calipers. Any suggestions?

Describe exactly how you're bleeding the brakes.ABS brakes have a slightly different technique.

[bocutter Ed]

Bike is a 1985 K100RT with ABS.

Is your ABS a retro-fit?

[Laitch]

Is your ABS a retro-fit?

We need some photos of this bike. Until then, watch this.

[Filmcamera]

if it is an 85 and has ABS it must be a retro fit.

 Either way start with bleeding at the ABS modulators then the caliper furthest from the Master Cylinder then the one closest.  It does take a lot of pumping - three or four reservoirs full of fluid I would say to be safe.

[85-K100-Cafe]

I did the usual, after filling out reservoir i pumped the front brake lever a few times, held the brake lever, loosen the bleeder valve and tighten the valve up before releasing the break levers. I am not well versed with K100's, this is my first BMW so i am not sure if the ABS is retrofit yet along what that even means.i never knew about the ABS modulators. How do i bleed the modulator? And where is it located?

[Filmcamera]

The modulators are just behind the battery on the left and right side of the bike - assuming it is ABS 1 that was retrofitted.  The left hand side just behind the gear lever is the front modulator and the right hand side behind the rear brake is the rear brake modulator - assuming they were retrofitted in the same place as the factory ABS. What makes you think you have ABS at all - as far as I know it was not introduced until 1989 on the K100 RS SE and whilst it is possible to retrofit it I cannot see many people bothering.

To check just follow your brake lines and see where they go.

A photo of the bike would help...

[rbm]

The 1985 K100 never had ABS brakes from the factory.  Therefore, the previous owner took all the components from another later model K100 and added them to this bike.  That is a seriously major undertaking.


The modulators are those two huge canisters on either side of the bike just above the passenger foot pegs.



This is the correct ABS bleeding procedure