Motive & Brake Bleeding Questions

[rick3000]

I just wrapped up my first brake bleed/flush. I pressured tested the system, poured 2L of ATE Super Gold into a Motive Black Label, then pumped to 15psi. I decided to avoid the hassle of removing the strainer and just pump the old fluid through the system. I began at the right rear outer bleed valve. I got about 800ml, which was likely overkill, but I wanted to make sure I got all of the old fluid out. I then got about 100-150ml from every other valve. I ultimately got about 1.5L out of the system, with about 0.5L left in the bleeder.

I am not quite sure I did everything correctly, so I am hoping for some clarification on the below questions:

-The Motive fill tube had some air bubbles in it for the entire process, I read that it is normal. Is that correct?

-The valves bled very, very slowly. I read to not open the bleed valves more than 1/4 turn, should I have opened the valves more?

-The air bubbles I saw escaping where very tiny, is that normal? I was expecting more like pockets of air between the fluid.

-I had a lot of trouble distinguishing between the new and old fluid. If I did not bleed any of the valves long enough, do I need to be concerned?

-Is it even possible to disconnect the bleed valve tube without getting some brake fluid on the calipers? I wiped what I could, then sprayed the area with water to try and neutralize/dilute any brake fluid that was left on the calipers.

Thank you so much in advance!
-Rick

[Deadeye]

Hi Rick, I open the bleeders apx 1/2 turn for a quicker job. I also use the power bleeder dry and just add fluid into the reservoir as I go. I also put a quick disconnect in the hose between the Motive tank and the MC reservoir so I don't have to pump it up every time I add brake fluid. 20 psi works well for me in the tank

[JayG]

You are fine

Air bubbles in the motive fill tube is normal/fine. It just keeps up the fluid level in the brake reservoir.

I found the bleed is slow as well and very difficult to see the fluid change. Those morons that outlawed ATE blue should be shot.

When I bled my brakes, I measure the volume as well. IIRC, its around 200 - 250 per caliper with the fronts being less that the rear and clutch. I found the correct amounts in a post here or on rennlist 996 forum. 1 liter is more than enough to do the job

If you open the bleeed screw too much, you can induce air into the stream and that can be the small bubbles you saw

[Burg Boxster]

+2 for using dry

As for your other questions:

Originally Posted by rick3000

-The Motive fill tube had some air bubbles in it for the entire process, I read that it is normal. Is that correct?

Yes, for most part correct. When used dry it's just one big air bubble.

Originally Posted by rick3000

-The valves bled very, very slowly. I read to not open the bleed valves more than 1/4 turn, should I have opened the valves more?

1/4 to 1/2 is sufficient

Originally Posted by rick3000

-The air bubbles I saw escaping where very tiny, is that normal? I was expecting more like pockets of air between the fluid.

Depending on usage for vehicle and time from last flush/bleed - yes normal. Most of old fluid gets expelled by caliper furthest from M/C (right rear in this case). You should 'see' less debris and bubbles as you move closer (and thus require less fluid from each as well). Just like much less fluid needs extracted from outside bleed valve versus inner.

Originally Posted by rick3000

-I had a lot of trouble distinguishing between the new and old fluid. If I did not bleed any of the valves long enough, do I need to be concerned?

If hard to distinguish then fluid was likely in better shape than most. Again, usage dependent but min every 2 years or before each track event.

Originally Posted by rick3000

-Is it even possible to disconnect the bleed valve tube without getting some brake fluid on the calipers? I wiped what I could, then sprayed the area with water to try and neutralize/dilute any brake fluid that was left on the calipers.

Indeed tough and dependent somewhat on length of tube used (tip to go buy a longer one at local hardware store for next time). You can usually finagle most of expelled fluid out of tube being patient for it to siphon out while holding catch container well below caliper after bleeder valve closed when disconnecting. I clean up drips w/ brake cleaner or denatured alcohol (also recommended to clean out Motive bleeder used wet; dry = none needed of course).

Aside from making sure you don't loosen bleeders too much... also do not over tighten.

Your trepidation rises from task being easier than you imagined. It's normal... especially when not simultaneously shelling out ~ $150-200 at shop for them to perform.

Congrats on job well done.

[rick3000]

Thanks for the replies! It did feel too easy.

[hancock1701]

Originally Posted by Deadeye

Hi Rick, I open the bleeders apx 1/2 turn for a quicker job. I also use the power bleeder dry and just add fluid into the reservoir as I go. I also put a quick disconnect in the hose between the Motive tank and the MC reservoir so I don't have to pump it up every time I add brake fluid. 20 psi works well for me in the tank

Can you explain please explain how you would use it dry? So you have a quick disconnect between the Motive tank and the reservoir. When the tank is still pressurized, you quick disconnect it, open up the reservoir, add fluid, replace cap, then quick connect again?

[JayG]

Originally Posted by hancock1701

Can you explain please explain how you would use it dry? So you have a quick disconnect between the Motive tank and the reservoir. When the tank is still pressurized, you quick disconnect it, open up the reservoir, add fluid, replace cap, then quick connect again?

Yup, that's how you use it dry
You do need to make sure you done run out of fluid in the reservoir, or you will need to re-bleed the entire system

It does save on having to clean the motive

[rick3000]

I will add a quick disconnect, and try keeping the Motive clean next time.

[JayG]

Its not hard to clean. pump the unused fluid back into its can

Rinse it out with water wipe the inside with some paper towels.
then rinse with alcohol (get 90% isopropyl or denatured ) and let it air dry

[clickman]

Does the OP have a Tip tranny? Otherwise I trust you also bled the clutch...

Oh, and you can still buy the ATE blue.

[rick3000]

Manual, I also bled the clutch. It took me a while to find the valve. It's pretty far up there. Where are you still finding ATE Blue, I thought it had been outlawed?

[ganseg]

If you don't bleed the clutch, does the new fluid work it's way into those lines? At two track events after sessions my clutch was engaging low and didn't come all the way up. Would bleeding it help or is this a different problem? 2001 S with 125k miles. I don't have any history before 100k. Brake fluid has been changed twice in that time (once by PO and now by me.)

[Steve Tinker]

You have to bleed the clutch separately.
The slave cylinder is not easy to get to ( I remove the triangulated aluminium chassis plate for easier access) but the fluid has to be changed out just like the brake fluid....

[ganseg]

Thanks for the quick answer. Could bleeding the clutch help with the problem I have had twice?

[thstone]

Originally Posted by ganseg

Thanks for the quick answer. Could bleeding the clutch help with the problem I have had twice?

Maybe. Maybe not.

Problem could be the fluid, slave cylinder, or the clutch itself. I'd start by bleeding the clutch and see if that helps (since its easy and cheap compared to the other possibilities).

[Gilles]

PS: Remember that you need to bleed the clutch with the pedal pushed all the way to the floor (if I remember correctly, the manual asks for "Several seconds..." ) thereafter, you can close the bleeder and pull the pedal back...