Brake lines and hoses, and are your brakes hanging up?

[TripleJ]

From the beginning, I knew with an old vehicle that I would be in for replacing any of the wearable parts in the brake system.  This was one of the reasons I chose this 85 holiday rambler.  It has a very basic hydroboost system behind a standard hydraulic 4-wheel disc brake setup.  Even the park brake is a separate unit, which further simplifies the service brakes.

One of the things I was looking out for was the problem that many people seem to have with the brakes releasing slowly, or 'hanging up'.  I found this exact issue when test driving my MH before I bought it.  The symptom was it would drive fine, and the brakes were good.  But I would get the feeling like it would get more and more sluggish off the line, like I had to use more pedal to get going and maintain speed.  It was most noticeable when I drove down my side street, which has 4 stop signs in a 1/2 mile stretch.  By the time I got to my driveway, the brakes were dragging heavily and actually beginning to groan and squeek a little bit.  If I drove past my house they would eventually loosen up, and continue on.

What I expected to find is that the interior of the brake hoses would be deteriorated and collapsed.  This would allow the brakes to be applied with the high pressure from the master cylinder, but the fluid would then not be able to force its way back out due to the collapsed hose. 

The hoses on my MH didnt look bad on the outside, but I bought all new ones anyhow.  So far I have changed the rear center hose and the passenger front hose. 

When I removed the rear center I sliced it several times with a razor blade to see what the cross section looked like.  What I found was that no matter how ruff the hose looked like on the outside, the inside was perfectly intact and the fluid channel was perfectly round.  No deterioration or sign of restricted flow.

When I worked on the front hose, the first sign of a problem was that when I disconnected the hose from the caliper, only a small amount of fluid dripped out.  I removed the hose and installed the new one.  Before reconnecting the new hose to the caliper I observed that the fluid was running freely from the open end.  Looks like I found the problem.

I sliced the old front hose and found that the inside looked the same as the rear.  Round and clean, at least until I made it to the hose bracket.  Here is a picture of the restriction where the bracket wraps around the hose



The bracket



I believe that the inside of the bracket where it contacts the hose is rusted and the rust must have built up between the metal and the rubber hose. 

Like I said, this hose looked fine from the outside, and the interior of the hose doesnt seem to be deteriorated at all.  Even the bracket doesnt look that bad, but it pinched the hose bad enough to where I tried, but couldnt blow air through.  I cant believe they pinched the hose too tight from the factory and it made it 70,000 miles this way, but its possible too I suppose.

I have three more hoses to do and Ill be looking out fr this same thing.

Keep in mind that if you have this issue, you would not be able to gravity bleed the system, and I doubt you would have much luck with a vacuum bleeder.  This is with varying results of course, depending on how bad the restriction is.

[Stripe]

Bloody good write-up mate..

[M & J]

With pics. Well Done!

[TripleJ]

Thanks guys. I know it's nothing profound, but just might be interesting to someone with the hanging or slow release brakes issue.

I was truly expecting the hose to be coming apart inside or something

To add, I did complete the front driver side hose also. Turns out the bracket was completely gone. Either damaged/knocked off somehow or maybe rusted away?  The hose underneath where the bracket use to be did show signs of having been similarly pinched as well. I will update this when I complete the rears.

[TripleJ]

I finished the rears, there were no brackets to speak of.  Brakes work

[JessEm]

One helped here.  Thanks 

I had a front brake stick within 20 miles of replacing pads and rotors. I only went 1/4 mile like that, but it smoked like a banshee. I stopped, and about 20 minutes later it came unstuck on it's own. From there I continued on, and haven't had a problem in the 100 miles I've put on since. Knock on wood... I had it looked at and they said the caliper might have got hung up... Now I know there's another possibility.