Fluid changes - Manual vs Automated Methods

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CA
I've just had some maintenance done and am planning on what else needs to be done, and have been considering the pros and cons of having the work done manually vs with some kind of machine. It seems that for brake fluid, using a machine that simultaneously adds fluid while removing old fluid from all 4 wheels is the superior method. If operated correctly (which should not be hard to do due to the change in fluid color being very visible), it would seem to be certain of exchanging all the fluid and minimizing the chance of adding air or moisture during the procedure. What are your thoughts on this? For ATF, I think a machine would be useful only if the pan was dropped as well and the technician made a point to cycle the transmission while the fluid was being exchanged. I also read that running the machine through the pump inlet, with the pan and filter removed, was more desirable. For power steering, the benefit of any machine would be to prevent the chances of air getting into the system, otherwise a manual process would seem to give as complete a fluid exchange. For coolant, I haven't looked into this much. I presume there is a chance that a machine could perform a more thorough clean by using more pressure but is there a chance of unsettling / loosening crud that you don't get out but which causes problems elsewhere afterwards. Be great to get peoples opinions on the best way for each of these changes. I know that I could do many of these things myself, but I'm firstly interested in whether a machine could be a superior way of doing any of them.
 
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19,686
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Sunny Florida
with brake fluid I simply put hoses on the caliper nipples and use gravity. Open the bleeders and periodically refill the master cylinder. What could be easier? ATF fluid exchange is as simple as placing the output line to your trans cooler in a bucket and running the trans until the pan empties. At the FIRST sign of bubbles, shut down and refill the trans. This is merely an abbreviated means of doing a full exchange. All the machines are is two containers, your own trans pump is doing the work. I change the filter every other time. We owned a B&G machine for years and it was just a box with two containers in it! PSF is so simple these days I generally just unhook a line on the rack while changing the oil. Then refill. Coolant gets tricky on many cars. But most mfgr's provide a detailed procedure to avoid steam bubbles/trapped air.
 

JOD

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3,577
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PNW/WA
my thoughts: be careful with generalizations. It may be model-specific. -for brake fluid, you may need a high-pressure system to adequately bleed the system. Unlikely, yes. By the clutch on my Volvo was one example. -for ATF, it probably depends on the routing of the fluid. A standard cooler-line flush works on most cars, but not all (it won't work on my Freestyle--drain and fill only). -for power steering, the simple line removal flush works fine for most cars--but not some Fords. I had to basically make my own tool to purge the air out of the system and re-fill, so I'd stick to just sucking out through the reservoir and adding fluid if you own a Ford, or building some sorta contraption to add fluid as you run out the old stuff (I'm not the only Ford owner to experience this, and it's obviously an issue since it's called out in the FSM. That's where I got the idea for tool I built). -for coolant, I use this. I'll never fill coolant any other way.
 

rjacket

Thread starter
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1,107
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Originally Posted By: SteveSRT8
with brake fluid I simply put hoses on the caliper nipples and use gravity. Open the bleeders and periodically refill the master cylinder. What could be easier? ATF fluid exchange is as simple as placing the output line to your trans cooler in a bucket and running the trans until the pan empties. At the FIRST sign of bubbles, shut down and refill the trans. This is merely an abbreviated means of doing a full exchange. All the machines are is two containers, your own trans pump is doing the work. I change the filter every other time. We owned a B&G machine for years and it was just a box with two containers in it! PSF is so simple these days I generally just unhook a line on the rack while changing the oil. Then refill. Coolant gets tricky on many cars. But most mfgr's provide a detailed procedure to avoid steam bubbles/trapped air.
Ok but some questions for you: 1) Brake fluid - if this works then that's great. But why have I heard all this business about doing one wheel at a time and pumping the pedal? 2) ATF - does your method empty the torque convertor? I used a different and more complete procedure on my car. 3) PSF - does your method not introduce air into the system?
 

rjacket

Thread starter
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1,107
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CA
Originally Posted By: JOD
my thoughts: be careful with generalizations. It may be model-specific. -for brake fluid, you may need a high-pressure system to adequately bleed the system. Unlikely, yes. By the clutch on my Volvo was one example. -for ATF, it probably depends on the routing of the fluid. A standard cooler-line flush works on most cars, but not all (it won't work on my Freestyle--drain and fill only). -for power steering, the simple line removal flush works fine for most cars--but not some Fords. I had to basically make my own tool to purge the air out of the system and re-fill, so I'd stick to just sucking out through the reservoir and adding fluid if you own a Ford, or building some sorta contraption to add fluid as you run out the old stuff (I'm not the only Ford owner to experience this, and it's obviously an issue since it's called out in the FSM. That's where I got the idea for tool I built). -for coolant, I use this. I'll never fill coolant any other way.
Thanks So what are your thoughts on the automated methods (for someone who might not want to do the work themselves)? Specifically, if I wanted to get the brake fluid changed by a mechanic, it would seem that the automated method is superior to a manual method because it seems to remove the chances of a mechanic taking shortcuts.
 
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19,686
Location
Sunny Florida
Originally Posted By: JOD
my thoughts: be careful with generalizations. It may be model-specific.
Good point, and generally the first thing I mention.
 
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3,111
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Cincinnati
Depends on the car. My Honda's are all simple drain and fills for coolant, oil, diffs and ATF (provided you do it BITOG-style which means overkill). I don't do PSF ever, and I have my mechanic do the brake fluid every 3 years with his machine.
 
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