Help with Power-motive brake fluid change

[bkreigsr]

What am I doing wrong?
I drain as much of the old fluid out as I can, keeping the level above the outlet holes, by gravity drip, at the closest corner.
Fill the power-motive tank with new fluid
Connect to reservoir, pump in some pressure.
When I go the the furthest corner (R/R) and loosen the bleeder valve, the reservoir spits up all the new fluid down the over-flow tube onto the garage floor.

I am not a novice to this procedure, as I do my other 4 road cars once a year with no problem.
The only thing I do differently is get as much of the old fluid out of the reservoir as possible on the P-car.
Maybe I should wait until the hose is attached to the open bleeder before I pump up the pressure?
Maybe I'm using too much pressure?

This has happened twice, once in April on my son's SC and yesterday on my 930.

thanks in advance
Bill K

[Howard M]

I don't have the instructions in front of me, but don't you have to clamp off the overflow tube? The pressurized fluid can't tell the difference between an open bleeder valve and an open overflow tube.

[na2ub]

You need to clamp the overflow tube at the resovoir with hemostats or the like. Then, when you pressurize the bleeder, it will push fluid to your open bleeder valve. It doesn't take a lot of pressure, so have patience. Too much pressure can blow your overflow tube off. Make sure you clean up any spilled fluid as it will eat your paint. Check under the drivers floor board, too, for spilled fluid.

Doug

[bkreigsr]

thanks Doug and Howard.
Clamping the overflow tube makes sense.
I checked for fluid run-off, and fortunately the 930 has a braided flex line that connects to a hard tube that exits next to the LF torsion bar mount.
How much pressure do you guys use?

thanks
Bill K

[HarryD]

10 - 15 psi is plenty to get the fluid to flow.

[GaryR]

Originally Posted by bkreigsr

What am I doing wrong?
I drain as much of the old fluid out as I can, keeping the level above the outlet holes, by gravity drip, at the closest corner.

You shouldn't be draining anything. Drain it using the Motive's pressure out the bleeders.

Originally Posted by bkreigsr

Fill the power-motive tank with new fluid
Connect to reservoir, pump in some pressure.

By fill you mean put in about a QT? That's all you really need. Too much fluid in there and you may have trouble blowing the line clean and getting the reservoir level correct at the end. You must block off the overflow line or fluid will end up everywhere.

Originally Posted by bkreigsr

When I go the the furthest corner (R/R) and loosen the bleeder valve, the reservoir spits up all the new fluid down the over-flow tube onto the garage floor.

My guess is that has little to do with opening the bleeder and everything to do with an open overflow line.

Originally Posted by bkreigsr

I am not a novice to this procedure, as I do my other 4 road cars once a year with no problem.
The only thing I do differently is get as much of the old fluid out of the reservoir as possible on the P-car. Maybe I should wait until the hose is attached to the open bleeder before I pump up the pressure? Maybe I'm using too much pressure?

No idea why you aren't covering the floor with oil on other cars but if they have an overfill line and you are overfilling (which is exactly what the MOTIVE does) they should be dumping it out also. Follow the instructions on the bottle along with blocking the overflow, should work just fine.

[David in VA]

Sears sells these which work great:

http://www.sears.com/shc/s/p_10153_12605_00947051000P?prdNo=8&blockNo=8&blockType=

Used vise grips for a long time but it's easier to damage the hose with them.

[Tigerrat]

Some how, someway you'll need to plug off the overflow. Also you should have filled the reservoir with fresh fluid after removing the old to avoid pushing air into the system. But it sounds like you've now filled it. I never use over 10 lbs of pressure. Ken

[porschenut]

All of the step by step instructions are printed on the side of the bottle.

[Forza]

I use one of these to pinch off the reservoir hose:

Amazon.com: Lisle 22850 Hose Pincher: Automotive

[Thrlls]

Originally Posted by David in VA

Sears sells these which work great:

http://www.sears.com/shc/s/p_10153_12605_00947051000P?prdNo=8&blockNo=8&blockType=

Used vise grips for a long time but it's easier to damage the hose with them.

This tool worked great when changing out my fuel pump. Should work just as well for the over-flow hose.