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Discussion Starter · #41 · (Edited)
Stahlbus Bleeder Valves

I frequently bleed my brakes (about 3 times a year) and wanted an easier, cleaner, and quicker way to do it. I looked at some speed bleeders out there and realized they are not all equally designed. So, I found the design of the Stahlbus bleeder valves the best. Basically, it incorporates two separate parts. One part is the fixed main body which attaches to the caliper or master cylinder. The second part is the valve system, using a ball and spring bi-directional system. With this design, the brake fluid can travel one way or bi-directional, depending on the amount of turns to the screw. Now this process involves Brembo brakes and master cylinder. The same principle applies to stock brakes.

Before we begin the installation, we must remove the old shite stock valves. Here, the rear brembo caliper has its bleeder screw seized because I did not apply any thread sealant. The hex head is rounded out, and could not unscrew it. So, I used a hammer and punch to shock it.

It was still stubborn, so I used a bolt extractor socket, which did the trick.

Now before we remove the mangled bleeder valve, we must first close the hydraulic system to prevent brake fluid from spilling out. To do this, first remove the brake pads. Removing the brake pads will allow room for the brake pedal/lever to travel as the caliper pistons get pushed out. Next, press down as far as it will go on the brake pedal and keep it pressed. I used a zip-tie and wrench. Likewise, you can use a zip-tie with a weight on the end.

I decided to replace 3 brembo valves for the rear caliper, front caliper and the front master cylinder. This time around, I dressed the threads with thread sealant to prevent seizing. Torque the bleeder valves to their proper specification.
Main body:
M8 = 7~10 Nm
M10 = 17~20 Nm

Top valve containing the ball and spring valve:
8~9 Nm

Sorry, I've no idea where my stock calipers are, no data on OEM bleeder screw size.


You will need a long 10mm hex socket, which Stahlbus conveniently sells.

After removing the old bleeder screw, install and torque the Stahlbus bleeder valve.

Next, undo the zip-tie and let the brake pedal return to its open or rest position. At this state the hydraulic system is open again.
Then, unbolt and remove the rear brake caliper and reseat the pistons or push them back in flush. However, if the pistons are dirty, clean them with a toothbrush and soapy water BEFORE you push them back in. When the pistons and caliper are dry, install the caliper, brake pads and continue the bleeding process.
Have new brake fluid ready (I use Motul RBF 600), open the fluid reserve tank cap. Attach the speed bleeder silicone hose and bag to the bleeder head.
Using an 8mm spanner, turn the top body valve half a turn. Then, push on the brake lever to expunge old fluid and air pockets. Keep pumping at your heart's content or until you manage to flush all the old fluid and bubbles out. I just estimate how much fluid is needed to flush and fill the system (sorry didn't record the volume). Now you can pump with one hand and hold the beer with the other! Remember to re-fill the reserve tank as old fluid is ejected. Never let the reserve tank go empty. When no more air bubbles are seen and the fluid is no longer the colour of your piss, close the valve and top up the reserve tank at the full line. Clean-up any and all residual fluid in the valve hole using a tissue paper (Kleenex). Wipe the area clean of spilled fluid with a wet rag. Remember, brake fluid is an acid, it dissolves paint, so don't get it on your skin, water will neutralize it.

Such a simple job, I didn't spill one drop of brake fluid using this bleeder bag and hose.
I bought the additional aluminum dust caps. Optionally, simple rubber plugs will do.

Now for the front brake, the same principle applies. Remove the brake pads, pull the brake lever and secure it with a zip-tie to close the hydraulic system. Remove both OEM bleeder screws at the caliper and master cylinder. Install, torque and close both Stahlbus bleeders. Remove the zip-tie and let the brake lever return to its open/resting state. Unbolt and remove the caliper, clean and reseat the pistons. Install the brake caliper and brake pads. Bleed the caliper first. Finally, repeat the bleeding procedure for the front brake master cylinder.


After a test ride, check for leaks in the bleeder valve by inserting a tightly wound Kleenex (tissue paper) in the hole to see if it soaks up any fluid. Make sure the Kleenex reaches the base of the valve. If it is leaking, tighten the valve a bit. In the next test ride, if it continues to leak, perform the same leak test. Tighten the valve incrementally to a torque value of 8~9 Nm. When the Kleenex is no longer soaking up fluid, the valve is closed properly.

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