F1Addict

Anybody done the conversion with a new booster and master cylinder rather than one culled from a junkyard with the lines still attached? I'm swapping out my old (1989 XJ) single diaphragm booster and giant cast iron master cylinder for a new one. I have the whole thing installed and ready to go but it appears that the brake lines (from the proportioning valve to the master cylinder) require a different flare than they did for the old master cylinder. My old master had a convex nipple to accommodate a double flare. The new master cylinder has a concave port and I can't seem to get the lines to seal (when I depress the brake pedal it leaks fluid freely where the hard line passes through the compression nut.

I have tried remaking the flare several times with no appreciable improvement, that was before I realized the flare seat was different than the one in my old master cylinder.

Any advice would be appreciated. This is my first attempt at making brake lines so I am unfamiliar with the different types of flares although my research seems to suggest that everyone uses the double-flare for brake lines.

F1Addict

Here's a drawing I made that might better explain what I'm talking about...

4BangerDanger

I believe you can buy adapter fittings at most parts stores.

4.3L XJ

You can also buy bubble flare tools on Amazon.

F1Addict

Okay, so that requires a "bubble flare" and not a "double flare"? Is that what I'm looking for?

4.3L XJ

Here is one

F1Addict

Thanks for the guidance. Much appreciated.

unidentifiedbomb

Don't buy adapters, they can fail. I'd go buy some tube from a shop and start practicing. You can ask while you're at the store if they have a rent a tool program. When I did mine I got a WJ booster from a friend and double flared the WJ lines into the XJ master.

4.3L XJ

I got mine from a wrecking yard

F1Addict

I've got a double-flare tool with all of the dies and clamp. I've ordered the bubble dies that will work with my press and clamp. I've got a 25 foot spool of 3/16ths line and a straightener so I figure I'll be about the best flarer in Southern California by the time I'm done.

cruiser54

This is exactly why I suggest a wrecking yard for the parts. You can snag the hoses and only have to make a double flare. and, the tubes are flexible and easy to work with.

Domaas

I did this ti my 88. I bought a short length of bubble flare line, cut the flare of one end and made a double inverted flare for the proportioning valve. I think i cut the original line for the fittings to reuse on the prop valve. It was cheap like only 3 bucks for each line but then again I already own a flaring kit. And yes you absolutely have to double flare!

cruiser54

excellent way to do it.

F1Addict

I do not have time for wrecking yards right now. XJs and ZJs are not as abundant here in SoCal as they are in other parts of the country. I'm lucky if I can find ONE in the yard and if there is it's usually picked to the chassis. I ordered the booster from Quadratec. It appears to be an OEM Chrysler booster and master. They accidentally sent me two. I tried emailing them about the error but never got a response. Now I have a free spare. Try getting that at the junkyard!

I knew about the double flare, it was the bubble that threw me for a loop. I now have both a bubble and a double flare tool. I got the brake lines fabbed up and installed today. They don't seem to be leaking. I will bleed and test as soon as it stops raining which looks like it will be sometime around mid-March.

F1Addict

Just wanted to close this out with the final results. I got everything bubbled and doubled and hooked up and bled and everything works great. My brakes have never felt this good. I discovered that two of my bleeder nipples were completely plugged which means I was never able to properly bleed the previous system. That likely explains my poor brake performance. Thanks again for all of the advice.