For power steering sure, it does recirc. For brakes, it will help the master cylinder, but not the rest. Just open the bleeder and the fluid will flow though. Just keep the M/C topped up and give it time.
Changing brake and PS fluids?
- Thread starter VaderSS
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It would be mostly a waste of time with the brakes because there is so little circulation.
PS is another story though. How well it works depends on the ratio of the resevoir size to the total amount of fluid in the system.
On the 96 Chevy, the PS system is supposed to hold 1.5 pints (based on the owners manual) and the resevoir holds 1 pint (my measurement).
When you change the resevoir fluid:
(total-resevoir)/total remains in the system.
In my cars case, that's (1.5-1)/1.5 = 1/3 remains in the system.
So, after 4 changes 1/3 x 1/3 x 1/3 x 1/3 = 1/81 = 1.23% of the old fluid remains in the system.
YMMV depending on system and resevoir sizes.
The flid in mine had about 40,000 miles and was burt smelling. I did 4 resevoir changes, driving a day or two between changes and the fluid looked good but still smelled burnt. Then I ran ARx in it for a couple of thousand miles, did 2 more changes and now it doesn't smell burned. I think the ARx help with the last bit of cleaning.
The car has a reputation for being hard on PS fluid so I'm going to keep using good synthetic fluid and change the resevoir fluid each engine oil change if the PS fluid doen't look and smell like new.
[ July 27, 2004, 01:29 PM: Message edited by: XS650 ]
PS is another story though. How well it works depends on the ratio of the resevoir size to the total amount of fluid in the system.
On the 96 Chevy, the PS system is supposed to hold 1.5 pints (based on the owners manual) and the resevoir holds 1 pint (my measurement).
When you change the resevoir fluid:
(total-resevoir)/total remains in the system.
In my cars case, that's (1.5-1)/1.5 = 1/3 remains in the system.
So, after 4 changes 1/3 x 1/3 x 1/3 x 1/3 = 1/81 = 1.23% of the old fluid remains in the system.
YMMV depending on system and resevoir sizes.
The flid in mine had about 40,000 miles and was burt smelling. I did 4 resevoir changes, driving a day or two between changes and the fluid looked good but still smelled burnt. Then I ran ARx in it for a couple of thousand miles, did 2 more changes and now it doesn't smell burned. I think the ARx help with the last bit of cleaning.
The car has a reputation for being hard on PS fluid so I'm going to keep using good synthetic fluid and change the resevoir fluid each engine oil change if the PS fluid doen't look and smell like new.
[ July 27, 2004, 01:29 PM: Message edited by: XS650 ]
I agree with XS650 that changing the brake fluid is largely useless. It does nothing to protect the most vulnerable parts of the system such as the part of the caliper piston $$$ beyond the O-ring that seals the brake fluid in the caliper. At least every few pad changes, you need to replace the worn and aged rubber parts, and coat the pistons with silicone grease. Either rebuild the caliper or buy rebuilt calipers. You lose a bunch brake fluid every time, eventually replacing all of it long before it causes any problem.
Absolutely. It does a good job of cleaning the system if done right. You should flush them out at least every two years. There are several different ways to flush out the bake system that work well. My favorite is the old two person method where one person mashes on the brake pedal while the other operates the bleed screws. I prefer it because it moves the fluid through the system faster when you open the bleed screw. That will remove more crud from the system.
Just like a high speed of water will clean your driveway better than a slow stream of water will.
I like Speed Bleeders (they have a website) because I can change the brake fluid without a helper.
Brake fluid (denatured alcohol) is a constant moisture absorber. They sell dip-strips to test the percentage of saturation in your brake fluid.
The rubber parts only deteriorate when moisture content goes too high. And the moisture settles on the rubber to rot it. Bleeding the brakes at each change is good shop practice.
The rubber parts only deteriorate when moisture content goes too high. And the moisture settles on the rubber to rot it. Bleeding the brakes at each change is good shop practice.
Brake fluid is a polyglycol ether compound...maybe chemically an alcohol, but not denatured ethyl alcohol.
The biggest hazard of moisture laden brake fluid is that it can cause the brake fluid to flash to vapor under the heat of heavy braking--your pedal goes to the floor! If you don't crash, you'll at least need clean shorts.
Ken
The biggest hazard of moisture laden brake fluid is that it can cause the brake fluid to flash to vapor under the heat of heavy braking--your pedal goes to the floor! If you don't crash, you'll at least need clean shorts.
Ken
I am a chemist with 20 years experience in resins and rubber. I also worked 3 years in a brake shop. Brake fluid is a poly glycol. Denaturatured alcohol doesn't have a wet boiling point of 311 F. Yes it does adsorb moisture, but quite slowly sealed in a brake system. Moisture has very little effect on rubber. Rubber brake parts deteriorate because of heat, time, wear, and oxidation. Bleeding the brakes when the system hasn't been opened is a good way to rip off customers. Your post is a collection of misinformation.quote:
Originally posted by N2OIL:
Brake fluid (denatured alcohol) is a constant moisture absorber. They sell dip-strips to test the percentage of saturation in your brake fluid.
The rubber parts only deteriorate when moisture content goes too high. And the moisture settles on the rubber to rot it. Bleeding the brakes at each change is good shop practice.
I feel that there has been plenty of information posted here to make that statement debatable at best.
I did just this on the SHO the other day..bled the **** out of the brakes and it made a BIG difference; I must have slacked when I did my rear brake lines. I'll probably change my brake fluid every 2-3 years. True there's probably not a lot of circulation in the system...all the more reason for a good flush.
For the power steering I just turkey-bastered out as much ATF as I could out of the PS reservoir in-between bleeding each wheel and gave the system a good workout before removing another load of it.
Will probably remove/replace a quart a week or so until it's clean.
[ July 27, 2004, 09:29 PM: Message edited by: Virtuoso ]
For the power steering I just turkey-bastered out as much ATF as I could out of the PS reservoir in-between bleeding each wheel and gave the system a good workout before removing another load of it.
Will probably remove/replace a quart a week or so until it's clean.
[ July 27, 2004, 09:29 PM: Message edited by: Virtuoso ]
XS650 :
I did the drain & fill cycle on my F150 power steering. I also installed a 3/8" Magnefine filter on the return line to the resevoir. You may want to consider installing one - they are about $20 and probably good for several years.
I did the drain & fill cycle on my F150 power steering. I also installed a 3/8" Magnefine filter on the return line to the resevoir. You may want to consider installing one - they are about $20 and probably good for several years.
I did the drain and refill cycle on my '88 Mustang. Twice, because I had to replace both return hoses and I did them on two different days. It was one of the messiest jobs I have ever done on a car. The hoses were covered in a 1/4" thick layer of grime (they had apparently been leaking for some time, although I didn't notice any fluid loss from the power steering reservior).
It calls for Type F but I used Mercon.
It calls for Type F but I used Mercon.
So is it ever necessary to bleed your brakes?
Is it as simple as a siphoning (or turkey basting) the fluid reservoirs and refilling with new fluid? I thought I read that in another thread. But something tells me that the new fluid would never make it to the end of the brake lines, since Im 90% sure they dont recirculate. And I know even less about PowerSteering fluid, but Id assume it doesnt recirc either. Correct me if Im wrong.
Most manufacturers recommend fresh fluid as part of regular maintenance. ABS pumps can be especially sensitive to dirty fluid.
I have to admit here that this is a big "it depends". I'm sure that the vast majority of cars on the road have never had a flush and you don't see a lot of failures due to old brake fluid.
Our track buggy, on the other hand, gets quarterly fluid flushes as the extra heat generated at a track event tends to boil any water in the fluid. Here, a mushy brake pedal is *not* your friend. As a previous poster mentioned, SpeedBleeders are a big help for cars that see frequent changes. Our street cars get a flush every two years with the old two person method. My bride pumps the brake pedal and I work the bleed screw. She gets to tell everyone for weeks that she "did a brake job" ...
The general wisdom is to start at the brake that is the farthest from the reservoir when measured via the hydraulic system. Works for me.
Frank
Was that wise? I have a 1996 Ford Contour and the 5 speed manual tranny came with Mercon ATF and the PS came with Type F ATF. Since they already were using Mercon in the tranny wouldn't it make sense to use the same Mercon ATF in the PS rather than Type F if it was ok to do so. It would save Ford money to use one type of ATF for both the tranny and PS. Rather than use the, long outdated for transmissions, Type F for the PS only.
Whimsey
My theory on that is that someone at Ford didn't get the memo about using Mercon in the power steering units.
Ford changed their power steering fluid recommendation to Mercon in 1997/8 and as far as anyone has been able to determine nothing was changed with the power steering pumps or the racks.
Also, many people on the Contour.org site are using Mobil 1 synthetic ATF (which is a Dexron III/Mercon fluid) in the power steering units of those 95/96 Contour vehicles. (I also put Dexron III/Mercon in the power steering of my '96 Contour).
Other posts on this site about power steering fluid seemed to indicate that unless the system contains clutches (which excludes the Contour and the Mustang), the type of fluid used isn't very critical. If the power steering system does use clutches, then the type of fluid WOULD be critical because Mercon is a friction-modified fluid and Type F is not.
In any event, I think Dexron III/Mercon is much better for the power steering than nasty 16-year-old Type F, and I believe that Mercon uses better base oils because it is a newer specification. (Actually it's the Dexron III specification that makes it better, since Mercon predates Dexron III by 15 years or so).
The Type F you'll find on the shelf has likely changed very little from what was on the shelf in in 1977.
Ford changed their power steering fluid recommendation to Mercon in 1997/8 and as far as anyone has been able to determine nothing was changed with the power steering pumps or the racks.
Also, many people on the Contour.org site are using Mobil 1 synthetic ATF (which is a Dexron III/Mercon fluid) in the power steering units of those 95/96 Contour vehicles. (I also put Dexron III/Mercon in the power steering of my '96 Contour).
Other posts on this site about power steering fluid seemed to indicate that unless the system contains clutches (which excludes the Contour and the Mustang), the type of fluid used isn't very critical. If the power steering system does use clutches, then the type of fluid WOULD be critical because Mercon is a friction-modified fluid and Type F is not.
In any event, I think Dexron III/Mercon is much better for the power steering than nasty 16-year-old Type F, and I believe that Mercon uses better base oils because it is a newer specification. (Actually it's the Dexron III specification that makes it better, since Mercon predates Dexron III by 15 years or so).
The Type F you'll find on the shelf has likely changed very little from what was on the shelf in in 1977.
According to Big Jim, in a post dated 7/29/02, on Contour.org forums archives:
"The 95 and possibly the 96 manual specified type F transmission fluid. After that, the manuals specified mercon transmission fluid. Unofficially mercon has been used in power steering systems instead of type F for years."
Big Jim used to be a Ford dealership service manager, so he speaks with some authority on this subject.
"The 95 and possibly the 96 manual specified type F transmission fluid. After that, the manuals specified mercon transmission fluid. Unofficially mercon has been used in power steering systems instead of type F for years."
Big Jim used to be a Ford dealership service manager, so he speaks with some authority on this subject.
brian,
Thanks for the info about the Contour PS. I've been doing the turkey baster PS fluid change method so I've stuck with the Type F. But If I ever get the courage to do a total drain and fill I'll give the Mercon a shot. But at this point in time I don't want to mix Type F with Mercon using the turkey baster method.
Whimsey
Thanks for the info about the Contour PS. I've been doing the turkey baster PS fluid change method so I've stuck with the Type F. But If I ever get the courage to do a total drain and fill I'll give the Mercon a shot. But at this point in time I don't want to mix Type F with Mercon using the turkey baster method.
Whimsey
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