WH brake lines

[47 dodge 1.5 ton]

I need some help from the experts here on brake line/cylinder compatibility. I am having issues with my brakes sticking and not releasing quick enough. I have all new wheel cylinders, shoes, cleaned all components very well and copper anti-seize all moving parts.

  My replacement hoses have an ID that measures 1/8” dot approved, original measures .190” and fluid passed through all. (Failed Dot inspection due to cracks). I did not change the bore size of the wheel cylinders. 
  I could not locate new springs, but seemed like they had a lot of pressure.   Master cylinder seemed fine before and seems to prime ok.

  Any thoughts or experiences? 
 

Thanks, Kevin 

 

Edited January 30, 2022 by 47 dodge 1.5 ton

[jsd245]

If they were working fine before, and you’ve  replaced the brake lines I guess I’d start there. The brake line that runs from the master cylinder to the  booster on my 1.5 ton is 5/16. I assume it’s that size for a reason. 

[47 dodge 1.5 ton]

I have not found a source for the original size. All replacement “break lines hoses” seems to only be available in an 1/8”. I have been told that stepping down from 5/16” to 1/8” at the frame hoses is not an issue because of the low volume of fluid moving through the lines. I’m having my doubts. Wondering if others have experienced similar issues and if they used smaller wheel cylinders?

Edited January 30, 2022 by 47 dodge 1.5 ton

[jsd245]

I just bought 5/16 brake line at Napa. They had pretty much all sizes. 1/8, 1/4” and 5/16. Had fittings for all of them. 

[jsd245]

Rereading, it seems  you are talking about the individual hoses that go to each wheel. I’m not an expert, but it seems really unlikely that could be the issue.  Seem like 1/8 would be fine there.

[47 dodge 1.5 ton]

Yes, I am talking about the hoses, lines are 5/16”.  These are the front (2) and the (1) on the rear. I believe the rear is more of an issue.

[47 dodge 1.5 ton]

Duplicate— deleted 

Edited January 31, 2022 by 47 dodge 1.5 ton

[Merle Coggins]

Have you ensured proper free play on the brake pedal - master cylinder linkage? If your linkage is set too tight the master cylinder may not be returning fully, which can not allow the brakes to fully release. 

[47 dodge 1.5 ton]

Good point, I only tried backing off the shoes a little. I’ll see what’s there for adjustment.
 

 Going down the road when I let off the brakes, I’m picking up a drag that takes several seconds to feel full release. Acts like the springs are not strong enough or could use more. 
 

 Out of curiosity, does anyone know when the hoses dropped to 1/8” or the supplier that had 3/16” ID last?  I know by theory this “should” work as is but have not talked to anyone that actually used the 1/8” hose for the rear duals.

[jsd245]

I don't know what the condition of your brakes were before - again, it seems if all was working well, then you replaced some components then had an issue, seems checking the new components might be the place to start.  

 

But- on the master cylinder front, when I took mine off to rebuild, the tiny hole inside  it was totally rusted shut.  There are two holes inside that go to the cylinder bore from the reservoir. - one large, one tiny, tiny one   I think is called the compensating port? Mine clearly was allowing no fluid through it. This hole allows pressure to be released when the pedal is released. So I think when brakes are fully depressed, if this hole is not clear, you could end up with what you're seeing. 

 

It is extremely small this hole. I had real trouble finding something small enough to clear it, yet also stiff enough to get the rust out that was clogging it. I had some tiny, micro drill bits and the smallest one worked. Piano wire might also work but I didn't have any. 

 

I think with the master cylinder in the car you could probably tell if this is clear. When you first push on the brake pedal a pretty lively stream of fluid shoots out of that hole until the cup covers it and the cylinder pressurizes. You should be able to hear it unless your master cylinder is very full. 

Edited January 31, 2022 by jsd245
edit

[47 dodge 1.5 ton]

 Well decided to look at the master cylinder tonight. Cant see anything causing an issue but was surprised to see the fluid somewhat dirty. Note for future; Wished I had spend more time cleaning the entire system at once instead of just flushing while adding parts. Hoping I didn’t gouge the expensive wheel cylinders that I had sleeved in bronze last year. 
 

 Given more thought as I am pretty disgusted tonight thinking of how important FME is inside of equipment (I teach/preach classes on this!), seems I may have found a path to investigate further. 

Edited February 1, 2022 by 47 dodge 1.5 ton