planeguy67

No, it's a good question because there isn't any way to purge the air once it gets hooked up. However, the air doesn't have to get purged.

Provided you filled the reservoir to the top and securely hooked up the Motive Power Bleeder, this it what will happen when you pressurize it:

1. As the pressure increases inside the Motive, the fluid will start to rise in the clear connecting tube and head for the reservoir (area of lower pressure).

2. Inside the reservoir, pressure and gravity coexist. What basically happens is the fluid sinks to the bottom and into the brake/clutch system and the air rises to the top (actually, the air just stays at the top).

3. So while you are bleeding the system, your reservoir will have a small amount of air trapped at the top the entire time. Don't worry, that little slug of air will never get into your brake/clutch lines so long as the Motive is full of fluid and keeps the reservoir charged.

4. If, however, you let the Motive empty (like I once did, Doh!), it will introduce plenty of high quality atmospheric air into your system. DO NOT let this happen!!!

5. Once you are done bleeding (the car, not your body), you have to disconnect the bleeder somehow because Motive didn't design the unit to travel around in the car with you. If you just relieve the pressure on the Motive by unscrewing the pump handle and letting the air hiss out, you may find the reservoir is still very full.

6. You can either draw the extra fluid out or do what I do: Lay the Motive on its side so the uptake straw inside draws air instead of fluid and continue bleeding the nearest caliper. The fluid in the reservoir will slowly fall while the Motives replaces it with air. When the fluid reaches the proper level, close the caliper bleed screw, depressurize the Motive, and disconnect it... no fuss, no muss.

7. Or you can use the pure air idea and simply fill the reservoir with fluid, connect the Motive empty and simply use the air pressure to push the fluid through the system. However, you will have to closely monitor the reservoir level and refill it when it gets to low. For an entire system flush it may take a few repetitions.

Have fun.

InTheAir

Does the Motive PB come with the tool for opening the nipple on the caliper?

AOW162435

When I first used the Motive in the fashion I described, I was doing a complete brake system and clutch circuit flush. I simply made sure to keep an eye on the reservoir level. It's not like the nipples flow 5 g/pm or something Since my nipples were somewhat clogged, and looked a bit old, I opted to replace them and the rubber caps.

As an aside, flushing the clutch circuit caused a super-smooth clutch pedal action to become jerky. After much back & forth on here, I decided to replace the rubber hose and the clutch slave cylinder. The thinking was that the new fluid changed how the seals within the slave act. Needless to say, I now have a very smooth clutch pedal and all is well. So consider this before getting the car on stands and flushing the slave cylinder! If it works fine, leave it for now. The old fluid in the clutch line really has no way of interacting with the new fluid in the brake system.

Andreas

Brave Heart

Unless I'm mistaken that tool looks like the tool you get to fix your bicycle

AOW162435

No. All you need is the correct size wrench - I think it's 11mm for the brake nipples and 7mm for the clutch slave nipple.

Andreas

InTheAir

Thanks, Andreas.

hn

Thanks. That was informative. This's the part I didn't think of:

planeguy67

I was thinking the same thing. It looks like one of those universal tools you keep in your bicycle pouch for on-road repairs. Well, maybe if your bicycle is a Huffy or Schwinn. You wouldn't catch me using one on my Specialized Allez Comp... or on my Porsche either!!!

Murray, use the right tool. And don't tell us you can't afford a nice set of wrenches when your car is sitting on a super sweet $150 Craftsman aluminum floor jack!!!

kkim

g_murray-

Just took a closer look at your pictures... re:safety- please tell me you also had the car supported with something else other than the jack pictured when you worked on the brakes?

mr_bock

I would like to add some additional helpful info.... I also just recently flushed my brake system. I search the web, and I think it might have been on p-car.com, I don't remember who posted it. To flush both sides of each caliper, you use some 1/4" clear tubing, a 1/4" 'Tee' fitting. Run about 6" of tubing into the ends of the Tee fitting and about three feet of tubing out the center fitting. Once the system is pressurized, you open both bleed fittings and flow fluid from both sides of the caliper. While this is going on, use a rubber or leather faced mallet and hit the caliper body. You will see junk and a few air bubbles com out. Do this to all four corners in the proper sequence, RR, LR, RF, and LF.

This worked great, and the pressure bleeder is a huge help.

Good luck.

InTheAir

I was going to mention that and then just thought I was too paranoid--I don't trust my jack to keep the car in the air, even if I'm not working under it.

g_murray

At any _one_ time, I only had ONE wheel off whilst bleeding that particular side's caliper. When I needed to do any other side I replaced the wheel on the side that was just 'done' (BEFORE I took the wheel of any other side). *** So, in effect, I always had 3 wheels plus a jack supporting the car.***

The Crapsman jack did the job, but yes, I AM getting a nice beefy set of jackstands in the near future. I wasn't too perturbed about just relying on the jack (this time) because I was working on the car 'from the SIDE' ...never 'underneath'. But thanx for the safety reminder anyways.

G.

g_murray

Oh man, I'm busted! My trusty Raleigh 'Road Ace' all-in-1 bicycle tool made its internet debut ...and y'all spotted it!

In my own defense, I went thru my 'collection of tools' and couldn't find ONE friggin' one that would fit over the thing without the potential for 'rounding out the corners'. So I resigned myself to first 'breaking-loose' the nipple with an adjustable open-ended spanner - then using the Raleigh-bicycle-tool to 'control the flow'.

Yesterday evening, after work, I moseyed to Pepboyz and went scoping for a METRIC set of ring spanners, beefy jackstands and a 'deep' lug-nut socket end for my torque wrench.

Phew!

G.

AOW162435

G.
When shopping for jackstands, remember that the 993 has four distinct jacking points underneath, and that these are flat surfaces. Normal jackstands will have a 'cupped' head which will gouge the surfaces. Some have devised adaptors that allow the top of the stands to be flat.

The other choice is a set of flat-top jackstands from AC. I finally broke down last year and purchased a set. They are absolutely bombproof and will outlive me. Do a search on here for these or send me a PM and I'll let you know where I purchased these. Once the car is sitting level on four of these, it would take an earthquake of biblical proportions to upset the car.

Andreas

g_murray

Answer: Whilst in the process of bleeding each side I started the engine and let it run for 10 secs. or so. Thus the engine was started FOUR times. Again, the engine was started WHILST fluid was 'flowing'. During the 10 secs. -- I would reach in to 'press' on the brake pedal _several times_. You just need to press it in 2 inches or so -- just to 'encourage' things a bit -- and it will 'self return' after each press. Just be careful NOT to press it all the way to the floor -- which, since there's nothing for the fluid to press against (because you have the bleed valve open!) -- you can easily do -- with just your hand. (Reminder: you do NOT want the brake-piston traveling down where it normally DOESN'T go!) So 'press/tap repeatedly' ...just don't jam it down to the floorboards each time!

With the engine now off...and still in the process of bleeding each individual NIPPLE -- I banged on the caliper (rubber mallet) so as to 'encourage' any (trapped/lethargic) air or particulates to exit. (And believe me I saw both!)
Thus there were EIGHT 'clobberings' per caliper.