Bleeding master Cylinders

[Sketchy_Racer]

Ok I think im missing something here,

I've tried two different master cylinders now, and the fucken brakes on the DR wont bleed up. They get to a point where there is pressure in the system, but the lever still comes back to the bars way to easily.

What the fuck am I doing wrong. Im gonna end up smashing shit soon cause this is really fucking me off.

Any ideas?

Cheers

[quallman1234]

The lever's not pushing in furthur enough?

[Buddha#81:Me]

Try bleeding the master cly only at the banjo fitting, Take the banjo bolt out and put your finger over the hole and.......lever in, finger off, finger on, lever out....repeat and this will at least determine wether the M/cyl is ok or not. Once you've bled the cly take the banjo out of the caliper and bleed the hose then the caliper.........very messy but it should work.

Get ya farken DR shitter out of our bucket thread ya little shit.

[FROSTY:Me]

Ok I think im missing something here,

I've tried two different master cylinders now, and the fucken brakes on the DR wont bleed up. They get to a point where there is pressure in the system, but the lever still comes back to the bars way to easily.

What the fuck am I doing wrong. Im gonna end up smashing shit soon cause this is really fucking me off.

Any ideas?

Cheers

You are using masters of the same bore as stock aren't you?
Wrong bore could mean soft as brakes

[Sketchy_Racer]

Yeah Im starting to think an RG150 caliper may have a smaller bore than a DR200..

Although I would have thought that the RG would be larger because it's supposed to power a twin pot caliper, and the DR is only a single pot

[Sketchy_Racer]

Issue has been found.

DR standard master cylinder is a 1/2" (12.7mm) the RG one is 11mm doh!

[TZ350]

Issue has been found.

DR standard master cylinder is a 1/2" (12.7mm) the RG one is 11mm doh!

I have found a lot of air can stay trapped in the banjo bolts. I bleed what air I can out of them by squeezing the lever and just cracking the banjo bolts. If that is not enough I undo the master cylinder and caliper, put a wedge in the caliper and tip them both up so the air in the banjo bolts can ex-cape. By holding the master cylinder on an angle and wiggling the lever air can ex-cape back into the master cylinder reservoir. Or tip the caliper so the air ex-cape's back into it and can be bleed out through the caliper bleeder.

When its all bleed properly a soft spongy feel can mean the master cylinder piston area is to small compared to the caliper piston area, a hard wooden feel happens when the master cylinder piston area is to big compared to the caliper piston area.

Another reason for a soft leaver is when the pads are soft and compress, or the pads are new and the disk is ridged, the pads then compress into the ridges. In this case the brake will improve as the pads bed in. The lever can also feel soft if the caliper and disk don't line up properly, in this case you will see the caliper mount or disk bend when you pull the brake on.