I got tired of mushy brakes on my 97 F-150 so I installed new pads and now (I am trying to) change the fluid. The right rear bleeder nipple wouldn’t come loose so I replaced the wheel cylinder. Now I can’t get the air out of the brake system. The left rear bled just fine but the right rear and BOTH front calipers won’t cooperate. I’m using a power bleeder and I could evidently suck fluid through the system forever and the air just keeps coming. I put Teflon tape on the bleeder threads but the amount of air gurgling through the power bleeder is way more than could be getting past the threads in any case. What’s going on? Where can all that air be coming from?

 

It's coming from your reservoir, if you are letting it go empty. The power bleeder is going to use a lot of fluid fast. You have to continually make sure the reservoir is full all the time. Back, right. Back, left. Front, right. Front, left. Is someone pumping (15 to 20x) the brakes and holding the brake down when you release the bleeder valve? Since you put new cylinders on, you may have to go around several times to get all the air out.
Good luck!

 

No, the reservouir has never gone dry, I have an assistant
who keeps it topped off.
No, nobody is pumping the brakes, that's what the power
bleeder is for.
-Thanks.

 

Sorry, I was thinking one thing from another thread that I read and wrote another thing.

 

If it matters, it’s a 4x4 Lariat.
I have a Haynes manual and it doesn’t say anything special about bleeding the brakes on this ABS system. The guys at the local NAPA store say it’s a big deal bleeding this ABS system and I’d better take it to a shop where they know the secret voodoo bleeding procedure.
I don’t know, maybe I just need to buy a gallon of brake fluid and keep sucking until I get all the air out somehow.

 

I'd fill the master cylinder and try gravity bleeding it first. Work in the reverse direction that you normally would, i.e. closest bleeder first, leave the cap off the master cylinder, open the bleeder, sit back and have a beer. Wait for fluid to drip fairly consistantly out of the bleeder, close it, move on to the next wheel.

 

Using a vacuume bleeder on a new wheel cylinder, air tends to get sucked between the treads of the bleeder screw. One thing you can try is removing the bleeder screw and place the end over the opening of the caliper/wheel cylinder. Remember when using vacuume the fluid will draw back into the system with air if released too soon. All else fails, get another person to pump the brake while you open. As far as the ABS, if you didn't run it dry, don't worry. A trick to bleed an ABS unit is to get as much of the air out as possible, then hit a dirt road and cram on the brakes to activate the ABS (will not work on some GM's).

 

Opening the bleeder and having someone step on the pedal might work too. Don't pump it up...open the bleeder, have someone press the brake pedal (don't let it go all the way to the floor), close the bleeder, repeat.

 

I had a guy I know at Ford hook up the Ford New Generation STAR tester in the dealer parking lot.
Special bleed routine "purges" abs pump, then I bled at home again ,pedal better now. Autozone could not do it, Ford manual calls for it. Mark

 

Thanks for the advice everyone. Quintin’s gravity bleeding worked fine, as far as I can tell there’s no air left in the system at all. Unfortunately, even with fresh fluid the brakes on this thing are still mushy and awful. I installed new ceramic pads from NAPA hoping that would help but it’s actually worse now (yes even after the pads are warmed up).
Did the 97s just have lousy brakes or am I missing something? (The truck has 114K on it now BTW). Is there some trick to making the brakes on this truck work? It seems the petal travel has always been way more than most other vehicles and the stopping performance dismal. Any tips for improvement guys?

 

Maybe your flex brake lines are worn out and expanding when you brake. You could replace the lines, maybe even some braided steel lines. And you probably should bleed one more time after about 100 miles since solving your first problem.

And you did properly bed the pads, right?

 

It has been my experience and other Ford owner friends of the same vintage (97,98) that the brakes on these years are less than what should be expected. I have a 98 and there has never seemed to be enough in the stopping department. Many people opt to go to four wheel dics but I don't know if that really helps the situation, not to mention the cost factor.

 

Thanks 69.
You know, if this were a motorcycle that's the first thing I would have thought of! I guess I assumed a big Ford truck would have heavy duty break lines, but I'll bet I assumed wrong. The squishiness in the breaks has to come from SOMETHING, my guess is your right, it's cheap flex lines.
So I'm installing braided steel lines just as soon as I can find a good supplier with reasonable prices.

-SJ


[QUOTE=69aries]Maybe your flex brake lines are worn out and expanding when you brake. You could replace the lines, maybe even some braided steel lines. And you probably should bleed one more time after about 100 miles since solving your first problem.

 

I replaced, the front calipers, discs, rear brake pads and the left rear brake cylinder. I used a 2 power bleeders, one the sucks the fluid through the lines the other a pressure bleeder.

I have bled all 4 lines 3 times and continue to have a mushy pedal.

Any thoughts??

 

Do you have drum brakes in the rear? If so the shoes may not be adjusted up properly. Did you have a mushy pedal before you replaced the parts?