I was flushing my power steering fluid, when...

[Jartin]

I accidentally put replacement ATF (for my power steering) into the brake fluid reservoir. I realized my mistake and tried to sponge as much of the fluid out as I could, but still ended up with probably about 1/8th of a quart of ATF in my brake fluid. I had to drive my truck back home (~120 miles) since.

What could be my course of action now? I've looked around on the internet a bit, and seen that if I let it run its course I will have to completely replace the brake system, which I am really looking to avoid. Any suggestions?

Thanks

[klhansen]

I'd suck all the fluid out of the reservoir, then power bleed the entire brake system, running a good amount of brake fluid thru it to flush out as much of the ATF as possible. If you aren't having problems after that, I'd call it good. You may have issues down the road, but if the ATF didn't get down to the calipers, they'll probably be OK.

Sounds like the time a gas station guy dumped a quart of engine oil in the power steering reservoir in our 68 Dodge when we were relocating across the country. Of course it overflowed, showing him his mistake right away. He got a suction gun and sucked all he could out of the reservoir and topped it off with PS fluid. No damage was done, but of course the engine wasn't running at the time.

[RT]

I agree - flush it as soon as you can. The petroleum based ATF will cause some seal swelling if left in contact too long - that could cause some frozen calipers. If you get every bit out, you should be good.

[Jartin]

I don't have a power bleeder, and am now nervous about working on my truck, should I bring it to a shop, or buy the power bleeder and do it myself?

[RT]

You could do it with a MityVac or some other similar device. Where are you located?

[Jartin]

I'm at Keesler AFB on the Mississippi Gulf Coast. We have an Auto Hobby Shop, but I'm not sure what tools they have, and they're only open on the weekends.

[FMTRVT]

I’ll start off by telling you what you should have done as soon as you realized what happened for people in the future who may be reading this thread after doing the same thing: Put rags or paper towels under the M/C then grab the plastic reservoir and move it side to side and pull it off the M/C, thereby dumping all the oil contamination out before it gets into the “system”.

Here is a list of the common mix up fluid specific gravities, i.e. how heavy the fluid is:

ATF: 0.85-0.87
Motor Oil: 0.88-0.94
DOT 3 Brake Fluid: 1.05-1.07

So just dumped into the reservoir, oils and transmission fluid will stay up top. With the reservoir removed it can be cleaned with Simple Green, rinsed out with water then alcohol (removes all water and evaps quickly), then the reservoir can be reinstalled and new brake fluid added. Sometimes doing this bleeding is not necessary or just at the M/C line nuts if you tap the reservoir so the air within the top of the M/C bore is floated up.

Back to the OP.

You may be lucky enough that the ATF remaining never made it into the working areas of the hydraulic “system” (M/C and lines) if there was enough brake fluid in the reservoir to keep the ATF floating at the top. Then you can do as mentioned above.

As mentioned and read, petroleum products and brake system rubber do not get along. For liability reasons, any dealer or private shop will have to replace everything as they cannot afford the insurance risk of a possible future failure coming back tot them.

If you have already tried bleeding this mess out without first removing and cleaning the reservoir, you may have ATF anywhere in the system. A master cylinder, calipers, hoses, etc are not your real problem, the ABS controller is due to its expense.

You do not want to manually or power bleed unless the reservoir is completely free of any of the ATF / oil. Having a few molecules of oil in the M/C bore or downstream is just like being a little pregnant.

[Jartin]

My brake reservoir was filled to the max line when I poured the ATF in, but like I said, I've driven 120 miles or so (mostly highway) since I messed up. Do you suggest I try pulling the reservoir off and cleaning it, then flushing the system? Or something else?

Thanks

[FMTRVT]

With older reservoirs that have old brake fluid contamination on the walls it can be hard to see through the translucent plastic, but the first thing is to try to tell if the oil contamination has stayed at the top, fully separated from the brake fluid. Even if you were able to remove all of that oil through the fill port there still would be some residual oil left on the sides of the reservoir, and this is why many, including myself, often recommend just putting in a new M/C.

If this happened on my own truck I know that I would remove the reservoir by flipping it over once the o-rings released between the reservoir and M/C body so fluid would not contaminate within the body of the M/C, then meticulous check the remaining body for any oil. I would then be as meticulous in cleaning the interior of the reservoir.

If there is any oil remaining in the reservoir and you either manually or pressure bleed the system some of the oil is at risk to go downstream into the M/C, ABS, or calipers and slowly degrade a seal until you have a pressure system failure.

When reinstalling the reservoir the O-Rings need to be lubricated either with brake fluid or a very thin film of slide caliper grease. Any brake fluid that has not been caught by the rags or paper towels can be washed away with a water hose once the system is back together and fully sealed.

The safest thing is to replace the M/C; the really safe thing is to have a shop replace everything. (Had to throw that in here.)

[klhansen]

Jack's the guy to listen to. He's absolutely on target with getting all the traces of the ATF out. I didn't think about the expense of possibly having to replace the ABS module if it failed.

I wasn't even aware that the MC reservoir could be pulled off. Makes good sense to do that.

Maybe after removing the MC reservoir, start removing the MC at the ABS module end of the lines to be even more positive that none of the ATF got that far down the line. Then flush those lines before putting them back on with a new MC.

Good luck.

Your base Hobby Shop should have a power bleeder setup, but like RT said, bleeding can be done with a MityVac kit.

[FMTRVT]

You used to be able to get the reservoir by itself from Ford, base part number 2L454, but not sure if you still can. We often wiped out the fluid level sensor when installing our test plumbing and just putting on a new reservoir when decommissioning the truck was 1/2 to 1/3 the price of a new master. They are just held in place by the friction fit of the two O-Rings to the M/C body. Often you need a prybar to pull the reservoir out of the body and sometimes a soft-blow hammer to get them back in. We never replaced the grommets.

If his version of ATF stayed separated within a filled reservoir, he may only need to play above the M/C. Stroking the M/C will only bring fluid down into the back chambers of the M/C as the fluid will not go to the pressure side until the friction material wears away enough so fluid has to fill in the extra displacement needs through the compensating ports.

If the reservoir is going to get removed, he is better off keeping it filled with brake fluid rather then try to suck out the brake fluid and possibly letting the AFT move farther down into the reservoir. Just keep the cap on, pry it off and try to flip the reservoir over. He!!, you might as well keep adding additional heavier brake fluid and let the lighter ATF flow up and spill over the reservoir and M/C body.

Here's a post from another forum that I participate in (note - motorcycle forums tend to have really weird views about how brakes work) that may help the OP visualize the M/C even though this is discussion is about a single chamber M/C.

The GSResource Forums - View Single Post - Bleedin' brakes!

Even if a little oil did migrate into the M/C with fluid staying in the back chambers due to miniscule pad wear (120 miles) all he might need to change is the M/C. Really depends on fluid separation.

[Jartin]

I found new MC's on amazon for relatively cheap, would you suggest just replacing the damn thing?

Here it is:

Amazon.com

Amazon.com

[FMTRVT]

The link is broken.

If you are going to replace it I would get one from Ford. There have been a number of threads that I've participated in on this forum and other diesel sites where the person has bought a M/C from aftermarket sources only to find they could not get a good pedal due to bad seals. They installed a Ford purchased one and no problem.

You never mentioned year/model/motor of your truck but if your Ford parts counterman is willing to work with you a M/C usually can be walked out the door between $120 to $175 depending on the vehicle.

I don't have eyes/hands/money on this project so I can't tell you if to just work on the reservoir or get a new M/C. If you have anything like 150k miles on the truck and a history of not bleeding the brakes, then a new M/C will be a good investment. Also in that mileage range owners with hydroboost brakes have been dealing with rust buildup between the M/C and hydrobooster due to brake fluid leaking past the M/C seals, so again another good reason for a new M/C before getting bit.

If you are willing to wait for an Amazon part then consider Trousley Ford here on site as they will give you an excellent price.

[Jartin]

Here is the part:

Dorman M390530 Master Cylinder : Amazon.com : Automotive

Dorman M390530 Master Cylinder : Amazon.com : Automotive

Sorry for the broken link.

Specs on the truck: 2002 F-350 Lariat 4x4 w/ Cruise Control 222k miles, and no known brake leaking issues

I just spoke to the Service man at the Ford dealership, and he said the price of the part was $250 or so. I thought that was on the pricey side.

[RT]

Wow - the dealership has got the Christmas spirit, huh?

Here's the prices at RockAuto

RAYBESTOS Professional Grade Part # MC390530 - $46.79

MOTORCRAFT Part # BRMC27 - $123.79

Guess which one I would buy?