1968 Brake distribution block still leaking..

[TexAg]

Guys, I'm looking for some help. If you recall, I've had some brake issues over the course of the past year or so. To recap:

- Leaking brake line caused warning light to come on.
- Fixed leak, but couldn't reset light.
- Pulled distribution block and rebuilt to reset light, now leaking from two places.
- Rounded off threads to one line, and never could get the crush washer to seal.
- Pulled entire assembly again.
- Replaced the front brake cross over line (the one with rounded off fitting).
- Front driverside brake line was leaking at the reducer fitting. It appeared to be damaged, so I found reducer fitting on ebay and replaced.
- Still leaking.... ARGH!!

So, here's my question. I realize that to seal a flare fitting on the brake line the procedure is to just loosen and retighten several times to get a good seal. What about the crush washer? I don't want to over-tighten, but I don't know how tight is too tight.

Again, this is not a flare fitting. This is at the crush washer that is on the front of the distribution block. This is the reducer fitting that the front driver side brake line connects to.

How do I get this to seal? Do I just keep tightening? I assume that it takes a good bit of force to crush the copper washer, but I don't know how much?

Thanks, and I'm sooooo tired of brake leaks... unch:unch:

 

[CougarCJ]

I understand your frustration with those washers. I have looked for replacement ones with the concentric rings that go to the front brake hoses, no luck. Even from AMK.

You might try the hardware store and see if they have a brass washer in your size. Make sure to check the thickness too.

 

[franklinair]

I stock an assortment of copper washers. If I had a sample I may be able to match it.
(40 to 60 inch pounds torque should seal a copper washer.)

Neil

 

[TexAg]

Thanks, Neil. I'll see if I can get a size on it later. In the meantime, I guess I'll just put a little more oomph into and see if it will seal up.

Why do they use copper anyway? Wouldn't a rubber washer (brake fluid compatible) work better?

 

[dalorzo_f]

Rubber can degrade over time, I'd guess that was the rationale for an exposed washer under pressure. Copper is used on the brake lines at the and callipers on discs too, so would guess the soft metal was seen as a better option by the engineers.

I'd think you would have to be careful with rubber not to distort/crack it when compressing between the two faces, it might work.

As noted finding ones with the original style concentric ridges is tough, you can find thicker than OEM which I have found crush pretty well and have worked well for me.

A cheap selection that my have what you need.

http://www.harborfreight.com/80-piece-copper-washer-assortment-67526.html

You can reuse them but they need to be re-annealed to soften. Heat to red hot, then let cool. Have done that with reusing ridged OEM in the past with no problems (not the best way, but it does work)

Another thing to check may be if the brass faces are damaged, leaving less than a flat surface to seal against, and distorting/gouging the washer?? Thread the plug on with no washer and take a feeler gauge to see if the gap is consistent?

 

[TexAg]

Ok, I thought I was using a new one, but I don't know for sure. I'll see if I can find one locally. I was concerned about the brass surface, but it didn't leak before I took it apart, so I'm inclined to think that isn't the problem. Ill check it again anyway.

I do have another distribution block, so I may rebuild it and try that one instead, if a new washer doesn't work.

Thanks again guys, for all of your assistance. We'll see what happens. I'm getting really tired of taking this thing apart and bleeding brakes...

 

[lnevill]

Prop valve?

I had a leak I couldn't stop. Turned out to be an o-ring on the inside of the proportioning valve (the round cylinder with one line in, one line out). I had snagged the o-ring on the spring when reassemblying the unit and ripped a chunk out of it. There are a couple vent holes in the prop valve covered by a rubber d-ring. Roll back the d-ring and have some one push the brake too see if it is leaking from there.
In the process of tightening every other fitting, I managed to over-tighten and crush 2 of the cones for the pressure fittings. I purchase a new set-up from WCC and no more leaks!

Lee