Have a question about bleeding my brakes and replacing the brake fluid in my system. On past vehicles, I've always changed the brake fluid every year. I get a friend to help and just keep bleeding the system at each of the wheels until the master cylinder is only 1/4 of the way full. Then refill the reservoir, move to the next wheel, and repeat.

My F150 is the first vehicle I've had with ABS and I've heard that on some cars and trucks with ABS, bleeding the system the conventional way can cause damage to the brake or ABS system.

Can anyone give me advice on how to properly bleed the system (and in effect replace the brake fluid)? Many thanks - John

 

I'd like to know myself , Never heard of anything special to be concerned about so I wish someone would answer you.

 

ABS is separate from the hydraulic system. Bleed away........

And every year is a little excessive, imo.

 

I realize that an annual brake fluid change might be excessive, but it's an easy timetable to keep. I pick a time of year when the climate's right (usually February or March here in Florida) and I change the brake fluid, antifreeze, air filter, and transmission and/or rear end lube. I guess I get my habits from when I used to work in a quick lube and was faced everyday with one neglected vehicle after the next.

So maybe I spend a hundred dollars a year on something I don't actually NEED, but who doesn't?

 

i replaced all the lines on my crown vic. i bled them the regular way and had no problems. just make sure that master cylinder doesnt run dry.i agree in changing the fluid.ive never had a vehicle for more than 2 years but...when i buy a used vehicle i change it anyway. piece of mind. whats a bottle of brake fluid?? 5$ so...

 

Thanks for answering JohnG6 , Books are great and I have a Hayes for the F150 but they don't tell you everything. The book recommended changing fluid every 30K Miles and discussed how to bleed the brakes with a helper but never mentioned any concerns , Gland to hear there aren't any. I agree brake fluid is cheap , new fluid can get rid of moisture, dirt, air, and i call it snot some goop comes out occasionally .

 

This is both wrong and right - the ABS is not a separate system, the fluid from the master cylinder flows through the ABS unit to the wheels. But it is ok to bleed normally through the ABS unit. The only time it is a concern is if you put on a new ABS module that is dry. In that case, you need to use a computer to cycle the ABS while bleeding. Otherwise there would be air bubbles in some of the valves.

Since you are just bleeding your existing brake system, go ahead. There will be a small amount of trapped fluid in the valves, but not enough to be concerned about.

And generally speaking, yes it is excessive to bleed every year. But if you tow a lot, or just drive really fast and brake hard, it could be justified. Especially in a humid climate like Florida - the brake fluid is hygroscopic (absorbs moisture) and this increases the chance of brake fluid boiling. Some people that take their sports cars to track events will bleed the system daily... but they run much higher temperatures.

Brake systems are designed to not need to be bled just to change the fluid. The design specs for suppliers require this. The vast majority of drivers get by just fine with only bleeding when they change pads. I wouldn't bother changing the fluid unless you start to feel spongy brakes (a sign of high moisture content / air in lines)

 

I plan on replacing a defective EHCU and have a few questions:

Has anyone ever replaced a EHCU? Can you walk me thru it.

How can you tell if the EHCU is pre bled? Can I do this myself?

Can I replace the ECHU and replace all the fluid myself?

Appreciate the help.

 

I haven't done one on a vehicle, but I have hooked them up in the lab. You just have your brake line connections to do (2 from the master cylinder, 4 to the wheels... assuming 4 wheel ABS) and then there should be a quick-connect for the wiring.

It should say when you order it whether it is pre-bled. This means that there is fluid behind the valves... so you can't tell by just looking at it.

If it is not pre-bled, you will need a special electronic hook-up that cycles the valves while you bleed. It'd be cheaper to just take it to the dealer and have them bleed it after you're done.

If the unit is Pre-Bled then you should be able to do it all yourself, assuming you are somewhat mechanical. Just make sure you label the 6 brake lines before you take them apart so you are sure they go back to the same points on the new unit. It would also be good to have a torque-wrench so you can get the right torque on the brake fittings. This will ensure no leaks.

Good luck!