Replacing steel brake lines

[scottnh1970]

Oh, change the brake hoses too, especially the front. I had one lock up a caliper on a high mileage car recently. All that flexing causes them to deteriorate and act as a check valve.They are cheap at NAPA, a bit less if you have an AAA card.

I think it was under $30 out the door for the 2 front.

If you had a shop do one hose and bleed the system you would be out about $200. Definitely worth to do at this point. At this point it would be prudent to change these out for anyone doing a brake job on these trucks.

I did change all the hoses when I did the lines. I bought new front calipers last night. Then found that one of them had a seized bleeder! So I installed the working one and returning the crappy one tonight for another one....this is dragging on. Then I can finish bleeding and see if these breaks work.

 

[96eb96]

I did change all the hoses when I did the lines. I bought new front calipers last night. Then found that one of them had a seized bleeder! So I installed the working one and returning the crappy one tonight for another one....this is dragging on. Then I can finish bleeding and see if these breaks work.

Sounds like someone sneaked a cleaned up core in and returned it as new. I had that happen once.

 

[scottnh1970]

Got new calipers installed. Bled brakes, no bubbles. Bled rear to front. Pedal still goes to floor. I'm thinking I need to bench bleed the master cylinder. Do I have to remove the entire assemble from the fire wall (master/booster)? Did I damage the master at all with the pedal to floor?

 

[marragtop]

You should be able to bleed the master at the lines coming out of the master.

 

[scottnh1970]

I didn't see a bleeder screw on the master.

 

[scottnh1970]

Ok, I feel dumb. I see the bleeder on the MC. I will try that.

 

[96eb96]

Got new calipers installed. Bled brakes, no bubbles. Bled rear to front. Pedal still goes to floor. I'm thinking I need to bench bleed the master cylinder. Do I have to remove the entire assemble from the fire wall (master/booster)? Did I damage the master at all with the pedal to floor?

The master may have been damaged if its that old. You are forcing it to travel into unused areas, and there could be buildup that can destroy the seals. I still think there is some residual air however.

Consider a vacuum pump device to bleed the brakes, its available at harbor freight. Make sure to put a bit of grease or teflon tape on the bleeder threads. If the threads suck in air you won't know when the system is fully bled. Bleed 2 cups in the back and one in the front with that unit.

 

[scottnh1970]

Ok. Bled master cylinder from its bleeder screw. There were bubbles, now clear fluid. Now after pumping the breaks with engine off I get a build-up of press until the pedal travel is rock hard (not to the floor anymore). Once I turn on the engine, the pedal goes to the floor and no breaks!

 

[96eb96]

Ok. Bled master cylinder from its bleeder screw. There were bubbles, now clear fluid. Now after pumping the breaks with engine off I get a build-up of press until the pedal travel is rock hard (not to the floor anymore). Once I turn on the engine, the pedal goes to the floor and no breaks!

The power assist is probably compressing the air in the system. I would rebleed.

 

[scottnh1970]

Ok. I will try that now.

 

[scottnh1970]

Still no change. I rebled from rear to front and then MC. A bubble came out of the RR...that was it—all others were clear fluid, no hick-ups. Still very firm pumping brakes with engine off, but when engine on, to the floor.

 

[john93rangerstx]

for 60 bucks you can get a new mastercilinder from autozone cant hurt to put it in

 

[96eb96]

sometimes you need equipment to do a proper bleed, either pressure or vacuum. Not a tech, but this was in my experience.

I looked at the start of the thread and noticed 231K miles on the truck. The master is likely toast, that is another story. I would have definately changed it. All that bleeding probably destroyed it, it was probably on its last legs.

 

[scottnh1970]

It was the master cylinder. I replaced it and it still had some play in it. In the end took it to Ford for the ABS flush/reset. Cost $120. I now have brakes finally!

 

[96eb96]

Wonderful! Job well done! Now you have great brakes for another 250K miles!
They probably powerbled it thru the master cyl. and ran the ABS purge.

 

[scottnh1970]

Thanks!
They warned me I was lucky that the HCU was still operational. They stated that they can be damaged from air getting in and being trapped with fluid still inside. This causes extra pressure(combo of air and fluid) in the HCU chambers leading them to fail (I guess there are fragile components in there. All ABS purge did was electronically tell the HCU to open small camber values within the HCU and release whatever is still in there (air/brake fluid). They did this in conjuction with a power bleed. They said I was very lucky it wasn't damaged—the unit costs $2500. I said "maybe your price." Anyway I paid! Lesson learned.

I'm going to post pictures when I get home tonight of the work I did. Over the weekend I also installed a MAC cat-back exhaust (since the original also failed inspection) but will talk about that in a different post. Now just replacing the right rear parking brake cable in time for a re-inspection this Friday. Hopefully the parking brake will have no issues installing.

Thank god for this forum and it's members advice. I actually knew what I was talking about when I brought my truck to Ford! The dealership also checked all my work and said that it was done correctly—for whatever that worth!

 

[96eb96]

Yes, when you bleed with the master cylinder technique there is a risk of air getting into the valves. Especially if there is air in the master cyl. I doubt though it can be damaged, but Ford probably has more experience with it. At that age though I can see the risk being there.

The vacuum bleeder I mentioned minimizes that risk and usually the ABS bleeding is not necessary, but not always. It works by sucking fluid out the bleeder screws. I guess it all depends. When I did my ex I didn't touch the brake pedal during bleeding.

Another good thing is all the old crap fluid was ejected from the ABS HCU, that is worth it right there. Consider the $120 routine maintenance at this point.

I used to own the tools to do the ABS bleed. They would cost you a minimum of $200 for a special box and a cable adapter (also very rare and hard to find). I looked it up for another member. The other option is a $1000 scan tool, so you are ahead of the game there.

I didn't need to bleed the ABS after I replaced my lines...but YMMV I guess...

 

[scottnh1970]

I have a pressurized hand pump for bleeding, but it kept producing air bubbles from a loose connection to the bleeder I guess—could never get it right. It works better on my motorcycle. So I resorted to the "brake pumping method."

I was going to crack open the ABS again and try to suck out the air and fluid from the connection points using my hand pump but 1.) was afraid the pump would still produce bubbles as on the bleeders 2.) I would still introduce air into the HCU once I was done putting the screws back on the ABS. In hindsight, I started to rush at the end of this project and should have bench bleed the master cylinder as most of the air was in there when I replaced it. Not sure if it failed because of all my brake pumping and air trapped in there. However, a new MC is there now.

The only thing that can go now on the system is the HCU, since everything else is replaced. Live and learn.

Many thanks!

 

[Yooper_65]

Connection to HCU (ABS module)

Just finished this job on my 94 Explorer. Used M10X1.0 Male Bubble/ 3/8-24 Inverted Female adapter (AGS BLF-31C) at the HCU. From there ran about 18 feet of 3/16 steel line (AGS PAC-325) back to brake hose mounted to frame near rear axle. Also had to buy a 3/8-24 tube nuts (AGS BLF-10C-5). Borrowed a double flare tool from a colleague at the office. Total parts: $25.50. Total time: 5 hours. Hardest part was getting the old line with plastic frame clips out from area between the gas tank and left frame channel.
I crimped the old line about 1" from the HCU then cut on the farside of the crimp to avoid bleeding out the HCU. Ran the new line before removing the original M10 tube nut (and crimped line) at the HCU. When I finally removed it, I quickly screwed in the new adapter and attached the new line.

 

[joney]

Yes, when you bleed with the master cylinder technique there is a risk of air getting into the valves. Especially if there is air in the master cyl. I doubt though it can be damaged, but Ford probably has more experience with it. At that age though I can see the risk being there.

The vacuum bleeder I mentioned minimizes that risk and usually the ABS bleeding is not necessary, but not always. It works by sucking fluid out the bleeder screws. I guess it all depends. When I did my ex I didn't touch the brake pedal during bleeding.

Another good thing is all the old crap fluid was ejected from the ABS HCU, that is worth it right there. Consider the $120 routine maintenance at this point.

I used to own the tools to do the ABS bleed. They would cost you a minimum of $200 for a special box and a cable adapter (also very rare and hard to find). I looked it up for another member. The other option is a $1000 scan tool, so you are ahead of the game there.

I didn't need to bleed the ABS after I replaced my lines...but YMMV I guess...

On that topic (yes I realize it's an ancient thread) Is it true that if you 'block' the brake pedal (put a brick on it? Not sure what it means) the valves on the ABS unit will close, and you wouldn't have to do the ABS bleed? A relative needs to replace some brake lines, and I may be helping her. Not even a Ford, it's an 03 Tahoe. But ABS should be similar in that? Advice appreciated!