DIY (with pix!) -- Brake Fluid Flush Fandango
#16
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Originally Posted by hn
So my dumb question is, where do all the air in the tube go when you transfer the new fluid to the resevoir?
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.
#18
Seared
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ii) if your fluid is 'out of date' and/or no amount of bleeding is removing the 'squishy-cheese' syndrome from your brake pedal -- then I vote to fill up the 'motiv'PB'. Reason? You are FLUSHING ...not just 'bleeding' and the 'motiv-PB' will empty FIRST before your resevoir does. (And we all DON'T ever want the resevoir to go dry ....right?)
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
#20
Seared
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Does the Motive PB come with the tool for opening the nipple on the caliper?
Andreas
#22
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Thanks. That was informative. This's the part I didn't think of:
Originally Posted by planeguy67
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).
#23
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Originally Posted by Brave Heart
Unless I'm mistaken that tool looks like the tool you get to fix your bicycle
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!!!
#24
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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?
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?
#25
Three Wheelin'
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.
This worked great, and the pressure bleeder is a huge help.
Good luck.
#26
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Originally Posted by 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?
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?
#27
Three Wheelin'
Thread Starter
Originally Posted by 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?
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?
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.
#28
Three Wheelin'
Thread Starter
Originally Posted by 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!!!
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!!!
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.
#29
Seared
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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
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
#30
Three Wheelin'
Thread Starter
Planeguy67 asked:
"Just to make sure I'm clear on this, you start the engine for 10 seconds AND tap the breaks after each caliper OR just one time?"
"Just to make sure I'm clear on this, you start the engine for 10 seconds AND tap the breaks after each caliper OR just one 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.