Modified XJ Cherokee Tech XJ (84-01)
All modified tech questions. If it modifies your XJ beyond stock parts ask it here.

Dual Diaphragm Booster and Master

Old 02-23-2019, 12:59 PM
  #1  
CF Veteran
Thread Starter
 
F1Addict's Avatar
 
Join Date: Nov 2011
Location: SoCal
Posts: 2,380
Year: 1989
Model: Cherokee
Engine: 4.0
Default Dual Diaphragm Booster and Master

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 is offline  
Old 02-23-2019, 01:33 PM
  #2  
CF Veteran
Thread Starter
 
F1Addict's Avatar
 
Join Date: Nov 2011
Location: SoCal
Posts: 2,380
Year: 1989
Model: Cherokee
Engine: 4.0
Default

Here's a drawing I made that might better explain what I'm talking about...
F1Addict is offline  
Old 02-23-2019, 01:53 PM
  #3  
Seasoned Member
 
4BangerDanger's Avatar
 
Join Date: Dec 2015
Location: Knoxville, TN
Posts: 442
Year: 1993
Engine: 2.5L
Default

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

Last edited by 4BangerDanger; 02-23-2019 at 04:26 PM.
4BangerDanger is offline  
Old 02-23-2019, 03:18 PM
  #4  
CF Veteran
 
4.3L XJ's Avatar
 
Join Date: Aug 2008
Location: Chico, CA
Posts: 4,446
Year: 1986
Model: Cherokee
Engine: 4.3L with headers and full 3" exhaust system
Default

You can also buy bubble flare tools on Amazon.
4.3L XJ is offline  
Old 02-23-2019, 03:36 PM
  #5  
CF Veteran
Thread Starter
 
F1Addict's Avatar
 
Join Date: Nov 2011
Location: SoCal
Posts: 2,380
Year: 1989
Model: Cherokee
Engine: 4.0
Default

Originally Posted by 4.3L XJ View Post
You can also buy bubble flare tools on Amazon.
Okay, so that requires a "bubble flare" and not a "double flare"? Is that what I'm looking for?
F1Addict is offline  
Old 02-23-2019, 04:12 PM
  #6  
CF Veteran
 
4.3L XJ's Avatar
 
Join Date: Aug 2008
Location: Chico, CA
Posts: 4,446
Year: 1986
Model: Cherokee
Engine: 4.3L with headers and full 3" exhaust system
Default

Here is one

Amazon Amazon
4.3L XJ is offline  
Old 02-24-2019, 12:54 AM
  #7  
CF Veteran
Thread Starter
 
F1Addict's Avatar
 
Join Date: Nov 2011
Location: SoCal
Posts: 2,380
Year: 1989
Model: Cherokee
Engine: 4.0
Default

Originally Posted by 4.3L XJ View Post
Thanks for the guidance. Much appreciated.
F1Addict is offline  
Old 02-24-2019, 10:44 AM
  #8  
CF Veteran
 
unidentifiedbomb's Avatar
 
Join Date: May 2011
Location: DE
Posts: 5,600
Year: 1988
Model: Cherokee
Engine: I6 4.0
Default

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.
unidentifiedbomb is offline  
Old 02-24-2019, 11:23 AM
  #9  
CF Veteran
 
4.3L XJ's Avatar
 
Join Date: Aug 2008
Location: Chico, CA
Posts: 4,446
Year: 1986
Model: Cherokee
Engine: 4.3L with headers and full 3" exhaust system
Default

I got mine from a wrecking yard
4.3L XJ is offline  
Old 02-24-2019, 11:54 PM
  #10  
CF Veteran
Thread Starter
 
F1Addict's Avatar
 
Join Date: Nov 2011
Location: SoCal
Posts: 2,380
Year: 1989
Model: Cherokee
Engine: 4.0
Default

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.
F1Addict is offline  
Old 02-25-2019, 05:59 AM
  #11  
::CF Moderator::
 
cruiser54's Avatar
 
Join Date: Aug 2011
Location: Prescott, Az
Posts: 37,772
Year: 1990
Model: Comanche
Engine: 4.0
Default

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.
cruiser54 is offline  
Old 02-25-2019, 09:31 AM
  #12  
CF Veteran
 
Domaas's Avatar
 
Join Date: Jul 2011
Location: Oceanside So Cal
Posts: 1,045
Year: 88
Model: Cherokee (XJ)
Engine: 4.0 renix
Default

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!

Last edited by Domaas; 02-25-2019 at 09:14 PM.
Domaas is offline  
Old 02-25-2019, 08:16 PM
  #13  
::CF Moderator::
 
cruiser54's Avatar
 
Join Date: Aug 2011
Location: Prescott, Az
Posts: 37,772
Year: 1990
Model: Comanche
Engine: 4.0
Default

Originally Posted by Domaas View Post
I did this ti my 88. I bought a short length om bubble flare line, cut the flare of one end and made a double 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!
excellent way to do it.
cruiser54 is offline  
Old 03-03-2019, 03:34 AM
  #14  
CF Veteran
Thread Starter
 
F1Addict's Avatar
 
Join Date: Nov 2011
Location: SoCal
Posts: 2,380
Year: 1989
Model: Cherokee
Engine: 4.0
Default

Originally Posted by cruiser54 View Post
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.
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!

Originally Posted by Domaas View Post
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!
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 is offline  
Old 03-18-2019, 09:39 PM
  #15  
CF Veteran
Thread Starter
 
F1Addict's Avatar
 
Join Date: Nov 2011
Location: SoCal
Posts: 2,380
Year: 1989
Model: Cherokee
Engine: 4.0
Default

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.
F1Addict is offline  

Thread Tools
Search this Thread
Quick Reply: Dual Diaphragm Booster and Master


Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: