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Hey guys,

 

If it's needed: 1989 with old Renix 4.0 - stock dana 35

 

I am trying to do a WJ master cylinder / brake booster swap since the old one was rusted out with a leaky booster. In the process of installing it I accidentally crushed the proportioning valve when putting the lines in so I have to replace it.

 

I have put two new proportioning valves in but it leaks from the same two each time I thought I tightened it down without pushing the line in first so I put another in and clearly that wasn't the issue. I bought an XJ proportioning valve and will not be using the front brake line (deleting the special proportioning valve toward rear). I don’t want to throw another in there and just “tighten it down” because it’s about $80.00 (part + shipping + tax) with about a week and a half to get to my house and it would do the same thing.

 

Regarding the lines: I took the fittings off the old MJ brake lines and put them on the WJ brake lines that I pulled from the junk yard with the master cylinder and booster. I couldn't get a good flare using a tool from an auto store so I took it to a brake shop and had them flare it for me. The fitting on top toward the rear is 1/2" and the other one is 7/16", all other brake lines (bottom and on the side toward the rear) are the stock brake lines and flares.

 

Anyway, the ones that are leaking:

Top toward the rear

Bottom toward the front

(see picture – also has part number for new proportioning valve)

Screenshot_20200914-132831.png.73251f38879fceeebdd6cbaffd48a121.png

 

They leave indents like the line isn’t sitting centered.

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I push the line in first and make sure it’s sitting where it should be THEN tighten the fitting but it still does it. I can’t figure it out, the flares look okay (also pictured). But again, I’m new to this so I’m kinda stuck on where to go from here. Any help would be appreciated!

If it’s the flares then can someone recommend a tool that is different than the standard $15.00 one from the Auto store? That thing is too inaccurate for how accurate these flares need to be and I can’t keep bringing these lines to a brake shop because the flaring they do isn’t working either (plus I would rather not remove that bottom line to flare it and cause another issue with the fitting further on down the line. Maybe a hydraulic tool that isn’t the $300.00 one from amazon?

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Bubble flare is not the answer. Those flares in the photos are bad -- that's the problem. Let's take it from the top. un fortunately, our forum software makes it difficult to quote parts on a post, but I'll try to work around that.

 

"They leave indents like the line isn’t sitting centered. "

received_740495829851302.jpeg

 

Yeah, the raised seat in the valve body has obviously been gouged. The gouge is deep enough that I don't know if it can be made to seat without leaking.

 

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This one is damaged to the point that I think it can't be saved.

 

This flare wasn't pressed hard enough on the second pass with the flare tool:

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The width of the "face" at the end of the flare is too wide, so the width of the inverted taper is too narrow. In addition ...

 

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The flare is off-center to the tube. You can see that the flare extends farther toward the top of the photo than the portion extending below the tube toward the bottom.

 

My suggestion: Go on Amazon and buy a coil of copper-nickel (cunifer) brake line. It's more resistant to corrosion, which is always good. Plus, it's softer than steel, so it's easier to bend, it's easier to get good flares, and it might be soft enough to compress the flare and seal those damaged seats.

 

 

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I like the idea of the copper lines but in that case, I would need to rerun and flare two lines for a total of 4 perfect flares needed.

The bottom line which goes to the rear (and behind the gas tank, unsure on what type of flare is back there).

The top line which goes to the master cylinder which has a bubble flare (I can't find what size this would be). 

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None of the flares on the distribution block are “bubble flares” they are ”double” flares. See pic for reference. Tough to get get double flares straight with the bar style flare tool. Here is a simple flaring tool I’ve used and makes great leak free double flares in 3/16 every time: https://www.summitracing.com/parts/sum-900318

There’s also a really nice kit with fittings from SURR that I use every time I have a big brake line job. Comes with tons of quality fittings and good quality copper nickel tubing.

 

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8 hours ago, desert_rachel said:

I like the idea of the copper lines but in that case, I would need to rerun and flare two lines for a total of 4 perfect flares needed.

The bottom line which goes to the rear (and behind the gas tank, unsure on what type of flare is back there).

The top line which goes to the master cylinder which has a bubble flare (I can't find what size this would be). 

 

I don't know what to tell you. You have steel lines with bad flares, and they have damaged the seats in your valve bodies. Keep using those lines and you'll just destroy more proportioning valves. You need to replace those flares. If you don't want to run new lines full length, then cut the ends of and splice in new sections with proper flares.

 

https://www.amazon.com/s?k=copper+nickel+brake+line+3%2F16&crid=W5G2CN1KRWGA&sprefix=copper+nickel+brake+line%2Caps%2C194&ref=nb_sb_ss_i_1_24

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Thank you for the recommendation and info ghetdjc320, just looking for/researching the size of the bubble flare now that goes into the WJ master cylinder so I can replace that top line. The bottom line that goes to the back and is also an inverted flare, I checked last night so at least it's the same type. :L:

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Looks like 3/16 is the same as 4.75mm so as long as I get a tool that does a bubble flare for that size it should work out okay for the master cylinder. I think this will take some practice but at least copper will be easier to flare than those steel lines. Thanks for the help, just have to wait on the slow corona mail now.

  :thanks:

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6 hours ago, desert_rachel said:

Looks like 3/16 is the same as 4.75mm so as long as I get a tool that does a bubble flare for that size it should work out okay for the master cylinder. I think this will take some practice but at least copper will be easier to flare than those steel lines. Thanks for the help, just have to wait on the slow corona mail now.

  :thanks:


Personally I would use a good adapter for the bubble flares to inverted flare. That tool I linked doesn’t do bubble flares but it does oem quality inverted ones. The good tool that does both is about $200

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I ended up buying a hydraulic tool from amazon that can do both the inverted and bubble flares, I also bought the copper-nickel brake line. I'm going to try to flare the steel line on the MJ just because the tool can do it but more than likely I'll end up running the copper-nickel lines. Tool price is definitely expensive but I'll be converting another MJ to the WJ brake system sometime this year. Plus it will be nice to have a tool that can properly flare lines. I've found it's usually better to invest in tools that make the job easier. Anything for the hobby that makes 2020 less miserable :cool:

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9 minutes ago, desert_rachel said:

Anything for the hobby that makes 2020 less miserable 

think thats been a the case for a lot of people, hoping for good results

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