Swapping front brake lines

[Lt46]

Hi guys,
I've never swapped front brake lines before and not sure what to expect.
For example; how much fluid is lost in doing so? Should I do one side at a time, bleed that side and then jump over to the other and repeat? Swap both lines at one time and then bleed individually? Will the lines to the rear need to be bleed as well? I just don't know how much air gets into the system when doing this job.
Any help will be greatly appreciated. TIA

[Mekanic]

swap the lines than bleed. If you are needing to replace the line because of rust, I'd remove the old line and let the lines bleed the master cylinder dry. old fluid is a very bad theing. Most larger master cylinder will only hold between a pint and a quart.
Get a oil drain pan and you are ready.
Start your bleeding on the longest lines first then work you way towards the master cylinder.

[Lt46]

No, not replacing due to rust, due to age. I just flushed brake fluid last spring and replaced all 4 calipers/pads. Fronts got new rotors as well.
I'd rather not drain all the fluid. How do you stop that from happening once the front line is removed? I'd expect some fluid in the line to drain, but are you saying the master cylinder will drain completely once the hose is removed? If so, this sounds like a NASCAR pit stop project.

[subford]

When you say front lines are you talking about the "Rubber brake hoses"?

[Mekanic]

Quote:

Originally Posted by subford When you say front lines are you talking about the "Rubber brake hoses"?

Good question. which is it the steel lines or the rubber hoses.?
It probibly won't drain themaster cylinder completley. Either way.

Ok if you are just replacing the hoses here is one trick.
Before you unhook them from the calipers take vice-grips or a C-clamp and pinch off the hose to stop flow. (Do this ONLY on hoses that are never to be used again.)
Then unhook the hose from the caliper and install the new hose on the caliper. then unhook the hose from the other end and hook the new one on that end.

[ChuckNJ]

Please look closely at all the steel brake lines. I am a auto mechanic and a ford fan , That being said the brake lines here in the northeast are the worst esp on fords. If there is any noticable rust on them like flaky rust I would not hesitate to have them all replaced. I have replaced several thousand feet of steel brake lines in the last few years its a real weak link in the ford braking system gm has its issues too not as bad

[Lt46]

Well, it's a combination of steel and rubber, one to the left caliper, one to the right.
I hear ya Chuck, fortunately what I have still looks good. Probably has to do with it being a Florida coach that I moved North 3 years ago and is in hibernation for our winters.
Bleeding the air out of the fronts is a no brainer but what about the rears? Will that become necessary after I open the system?
TIA

[Mekanic]

Quote:

Originally Posted by Lt46 ....Bleeding the air out of the fronts is a no brainer but what about the rears? Will that become necessary after I open the system? TIA

Maybe, maybe not. you tell us. after you do the front you will know if the rear needs blead. if you bleed the front and they are still soft bleed the rear. if you do it that way i doubt you will need to do the front over again.

Remember the brake bleeding rule #1 keep the master cylinder filled.

[Lt46]

OK thanks

[John Wayne]

I sure would not like to bleed the master dry as this could also bleed the ABS unit dry and That is a BEAR to get all the air out of. I just replaced my front rubber lines just because they were getting old and it's easier to do it in the drive way then on the side of the road. You will loose some fluid but if quick enough the master will not go dry. Do one at a time and replace fluid between hoses I'd bleed the whole system after, better safe then sorry.

[falcor]

Just a suggestion. Check the master cylinder and see if it has two chambers. Been a long time, but I think that's a safety issue. One chamber front, one rear. That way you never have a complete brake failure in case, say a line rusts through. So draining one shouldn't affect the other.

[Nick-B]

Quote:

Originally Posted by John Wayne I sure would not like to bleed the master dry as this could also bleed the ABS unit dry and That is a BEAR to get all the air out of.

No ABS on a '97 chassis.

HOWEVER, if the master cylinder goes dry it can sometimes be difficult to get it purged of all air so it is still good advice.

[pacevette]

For what its worth I thought I would throw my 2 cents in on my experience with brake hoses..I had a 1996 coachmen on a f53 chassis. I replaced everything as you did. But my problem was that I could not find the left front hose. I ordered one from a parts store. When i picked it up I quickly realized it was 6" too short. They called around and I even made a call to ford. Ford told that they didn't even have a part number for it anymore. I looked for this hose for 2 weeks and never did find it. I eventually had to take it to a hydraulic hose repair company and.they had to make one for me. They took both ends off and pressed them on a new hose. This may not be our case bit if you do not already have one I would do my best to find one before you ruin it by pinching it off.

[Lt46]

Thanks one and all. The swap was uneventful but not without multiple expletives uttered. Steel brake line was a dog to loosen due to very tight spaces (within C-channel of frame rail). Bled and replaced fluid in MC as I went along. All is well. For those looking; part #'s were Bendix 78159 and 78158.