Changing the Brake Fluid

[Vlad Soare]

Hi guys,

It is time for me to replace the brake fluid in my GT, and I'm thinking of doing it myself. I've got a device that attaches to a compressor and to a bleed nipple and sucks the old fluid out.
My plan is as follows:

1. Raise the rear end of the car. Remove the rear wheels.
2. Insert the sucking tube of the device into the brake fluid reservoir and remove as much fluid as possible, but without emptying the reservoir. Leave a bit on the bottom, to avoid air entering the system.
3. Pour fresh brake fluid into the reservoir.
4. Attach the tube to the rear right bleed nipple, open the valve and start sucking the old fluid, until fresh-looking one comes out. Stop from time to time and check the reservoir to make sure it hasn't got empty. Add some more brake fluid.
5. When the brake fluid coming down the tube appears fresh, i.e. a bit lighter coloured than the one I started with, close the valve and move on to the rear left caliper. Repeat step no. 4 there.
6. Put the rear wheels back, lower the car, raise the front, remove front wheels.
7. Repeat step no. 4 with the front right caliper, then with the front left.

After each step, check the reservoir and add more brake fluid if necessary.

8. Top off the reservoir to the max line, put the cap back, job done.

My questions to you are:
- Does this look like a good plan? Did I miss anything?
- Does the ABS have any special requirements? I mean, does the fact that the car has an ABS change the above procedure in any way?
- I seem to have heard some time ago, though I'm not sure I'm remembering right, that six-piston calipers have two bleed nipples. Is that true?
- Any other tips or tricks?

Thank you.

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[paulm1]

Not familiar with the method you are describing using a compressor to create a vacuum. I use a hand pump pressure bleeder, first suck the fluid out of the reservoir, fill with fresh, fill the pressure bleeder tank about half way, pump it up to 25psi then open the calipers one at a time back to front. I think the pressure bleeder ensures the ABS module opens up. Vacuum won't open those valves.

 

[Vlad Soare]

I think the pressure bleeder ensures the ABS module opens up. Vacuum won't open those valves.

Good point. I've seen those pressurized bleeders, but the vacuum version was a bit cheaper and I thought the end result should be the same.
But if it helps with the ABS then I will look into getting one of those.
Thanks.

 

[luca1290]

You don't need to bleed the ABS unless you are changing the module, and there is the procedure in FDRS to do that.

Keep in mind that all brake fluid passes through the brake distributor which is embedded into the ABS unit. There is no advantage in performing a forced bleeding of the ABS unit if not needed as there is much of anything inside.

You're fine with what you have and your procedure is accurate. If you can you want to raise the car flat, but it will not change anything unless you manage to put air into the system.

On a side note, I managed to put air into my other car (the Mercedes bleeding procedure is idiotic and the car has no visible brake reservoir AND no visible instrument light for low fluid), bleeded like a conventional car, then via Xentry I bled the ABS module (which of course is not called ABS). Since the ABS did not activate there was no air to purge.

 

[kz]

Looks like reversed pressure bleeding procedure.

I will only add that Ford manual calls for actuating hand brake while bleeding rear calipers - and it typically results in 2-3 air bubbles coming out. Not a huge deal.

 

[WItoTX]

Good plan. Only thing I can add, make sure you buy a bit more fluid than you think you will need. I didn't expect the capacity in the system there actually is.

 

[Vlad Soare]

Good plan. Only thing I can add, make sure you buy a bit more fluid than you think you will need. I didn't expect the capacity in the system there actually is.

I have two 0.5 liter bottles. I believe the total capacity of the system is somewhere around 0.7 liters.
Will that be enough, or do you think I should get an extra bottle?

 

[tosha]

If you are doing this once in every few years on a single car, you can just ask a buddy to pump brake pedal.

If you have more than one car, but it's still maybe a once a year procedure for street only cars, and you want to save money, get one of these: https://www.amazon.com/HTOMT-Automo...9&sprefix=vacuum+brake+bleeder,aps,115&sr=8-3. Hand pump is ok for occasional use.

For frequent changes, like track cars, Motive pressure bleeder is the best thing I have tried so far. It's a bit of investment, but it is so easy to use and saves tons of times.

I have tried this one before pressure bleeder and it was complete waste of money: https://www.amazon.com/Capri-Tools-...&sprefix=vacuum+brake+bleeder,aps,115&sr=8-22

 

[Egparson202]

Service notes:

If you have 4 or 6 piston front calipers, they have 2 bleed screws on each caliper, bleed the inner bleeder first, then the outer bleeder.

On the rear calipers, apply and release the parking brake 5 times, bleed, repeat, until no air.

The ABS unit (HCU) must be bled if a new unit has been installed, along with a second pressure bleed.

 

[GT_MTL]

On the rear calipers, apply and release the parking brake 5 times, bleed, repeat, until no air.

This one is very important and often untold/forgotten !
Especially if you install new rear brake calipers.

 

[WItoTX]

I have two 0.5 liter bottles. I believe the total capacity of the system is somewhere around 0.7 liters.
Will that be enough, or do you think I should get an extra bottle?

I don't know the answer. I know I personally tend of have bad luck with these things (My pressure bleeder top blew off last time, and a ton of Motul 660 was spilled), so I always go double. But I also change fluid a bunch.

 

[Mrhavasu]

Good info, thanks.

 

[GTP]

I have two 0.5 liter bottles. I believe the total capacity of the system is somewhere around 0.7 liters.
Will that be enough, or do you think I should get an extra bottle?

That should be fine. I buy ATE200 in 1 liter cans, and if I don't waste much it is the perfect amount.

...
For frequent changes, like track cars, Motive pressure bleeder is the best thing I have tried so far. It's a bit of investment, but it is so easy to use and saves tons of times.
...

Many of us use the Motive, and we use it dry, i.e. just to provide the pressure at the MC but not as the source for pumping in fluid. Therefore, no need to clean the tank or hose afterwards. (Just keep a close eye on the reservoir level.)
You can find it with the proper screw-on adapter from OPMustang.

Another tip:
Open the bleed screw 1/2 turn which is enough to drain fluid but not allow air to enter back behind the screw tip.

I have methods that allow me not to have to obsess over fastener torque, but in the case of the bleed screws, DO use a 1/4" torque wrench to tighten the nipples to ~50 inch-pounds. You want a tight seal, but over tightening can damage the caliper seats which will then cause a leak.

 

[Vlad Soare]

Thank you all for your replies. Great info.
I decided to ditch the vacuum idea and ordered a pressure bleeder. I've also ordered one more pair of jack stands, so I can lift both the front and the rear at the same time. Anything that makes the job a bit easier or more comfortable is bound to help.
I'll let you know how it goes.

 

[Egparson202]

Thank you all for your replies. Great info.
I decided to ditch the vacuum idea and ordered a pressure bleeder. I've also ordered one more pair of jack stands, so I can lift both the front and the rear at the same time. Anything that makes the job a bit easier or more comfortable is bound to help.
I'll let you know how it goes.

With the car in the air and wheels off, the process will be straightforward. It does require some focus so be wary of distractions or interruptions. The right helper can be a good move too. The reward is a firm pedal. And what’s better than that? Nothing.

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