Jump to content

MJ Load Sensing Valve Delete Procedure


Recommended Posts

Revised yet again 19 Jun 07

 

There are several writeups around concerning the MJ load sensing valve delete procedure. I "borrowed" some members' pictures and procedure steps and wrote this up trying to organize and condense the procedure and eliminate some of the confusion. After looking at several procedures, this one I think is the easiest way to do it. It uses minimal fittings, requires no new brake line or re-flaring, and is the way I'm going to do mine after gathering the parts I need. If anyone sees any errors and/or omissions, please let me know before I post it up in the DIY forum. Thanks to SBpunk and kryptronic for photo contributions.

 

My Current Brake Setup:

Front: 96 dual diaphragm booster and master cylinder, stock disk brakes.

Rear: Dana 44 with Ford Explorer (Teraflex) disk brakes.

 

Parts Required:

 

              

Step 1. Remove the lower front brake line from the distribution block (#1 below) and plug the port. Use a 1/2x20 Inverted Flare Plug (Summit Racing, p/n EDD-120500).



Step 2. Follow the 3/16" brake line (#2 above) from the distribution valve block front snout port  to the T-fitting (#3 below) behind the gas tank. Disconnect the three existing lines at the T-fitting.

Image Not Found

Step 3. Install a 3/8x24 Gates inverted flare coupler (#4 below - O'Reillys, p/n G60693-0303) connecting the distribution block line #2 to the line that goes to the rear axle soft line. (#5 below).

Image Not Found



Step 4: Bleed system, check for leaks, and road test. If all goes well, remove the abandoned brake line and load sensing valve. DONE.

 

Note: Depending on your rear brake configuration (drums or disks, brake line condition, etc.) an inline adjustable proportioning valve (Wilwood or similar) may have to be installed in the rear brake supply line to prevent premature rear brake lockup. OR if you have rear disk brakes, replace the MJ distribution block with a proportioning valve from a front and rear disk brake ZJ.

Link to post
Share on other sites
  • Replies 104
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

Popular Posts

There is no "return" involved in the MJ braking system. One line is the normal line that runs through the height sensing valve, the other is an emergency circuit that bypasses the height sensing valve

Posted Images

Clarification - are you removing and plugging the line to the load sensing valve (at the front of the distribution block marked #2) or the rear brake line at the bottom front of the block (marked #1)? Based on Step 3, I assume you're disconnecting the line marked #1 as you reference the distribution block snout line being connected to line to the rear axle, correct?

I'm not happy with my braking and have a '96 booster and master cylinder in the garage and on the to do list. If that doesn't drastically improve braking, my next step is eliminating the load sensing valve.

Link to post
Share on other sites

Clarification - are you removing and plugging the line to the load sensing valve (at the front of the distribution block marked #2) or the rear brake line at the bottom front of the block (marked #1)? Based on Step 3, I assume you're disconnecting the line marked #1 as you reference the distribution block snout line being connected to line to the rear axle, correct?

I'm not happy with my braking and have a '96 booster and master cylinder in the garage and on the to do list. If that doesn't drastically improve braking, my next step is eliminating the load sensing valve.

 

 

The booster difference is huge. You can also use a 99 to 2004 WJ booster/master.

Link to post
Share on other sites

I did a write up in the tech section. Deleted mine and put in a 96 XJ MC/Booster. Have an 8.8 with disk brakes now and it will put you into the windshield on 31's if you hit it too hard.

 

 

If you do end up swapping your booster I'd throw in some new YJ front soft lines and chevy rear soft line. Gives you a couple extra inches if you decide to lift higher.

Link to post
Share on other sites

I did a write up in the tech section. Deleted mine and put in a 96 XJ MC/Booster. Have an 8.8 with disk brakes now and it will put you into the windshield on 31's if you hit it too hard.

So you deleted the distribution valve or just the height sensing valve when you did the booster? 

Link to post
Share on other sites

I kept the original block and got new lines at orielly's that were correct sizes on the side going to the MC. Cut off the other end, added the original fittings from the block side and bent them in a easier to access route to make getting to the shock easier. Then plug up the bottom front line. Run the one going from the nose straight to the soft line down to the axle. That line might need to have the fitting changed and double flared depending on your model.

Link to post
Share on other sites

I've done 2 Comanches and 1 Cherokee with upgraded boosters.

1 Comanche has rear drums. The other has rear discs as does the Cherokee.

 

On the Cherokee I just swapped out the prop valve guts from a 94 to 98 ZJ.

Works great.

 

First Comanche with rear drums disappointed me when compared to the XJ and gave me premature rear brake lock up.

Added an adjustable prop valve to reduce lock up. 

Overall braking performance decreased.

That's when I decided to do this like I've don on many others and delete the prop/distro valve and see what happened.

The orifice in the distro valve is .050" whereas brake line tubing ID is .100".

Using Ts and fittings from Napa I improved the braking performance a lot. I was able to put more braking to the rear with the adjustable valve than previously. Now it stops almost as good as the Cherokee.

 

The other MJ that I plumbed the same way stops as good as the Cherokee. 

Link to post
Share on other sites

I've done 2 Comanches and 1 Cherokee with upgraded boosters.

1 Comanche has rear drums. The other has rear discs as do the Cherokee.

 

On the Cherokee I just swapped out the prop valve guts from a 94 to 98 ZJ.

Works great.

I thought I was going to have to when I did the disk brake conversion but I guess, and I'm no expert, when I did the 96 booster and MC swap theres enough pressure with the MJ block to get the rear brakes locked up. I haven't upgraded the front pads yet. When its time definitely going to black magic pads.

Link to post
Share on other sites

 

I've done 2 Comanches and 1 Cherokee with upgraded boosters.

1 Comanche has rear drums. The other has rear discs as do the Cherokee.

 

On the Cherokee I just swapped out the prop valve guts from a 94 to 98 ZJ.

Works great.

I thought I was going to have to when I did the disk brake conversion but I guess, and I'm no expert, when I did the 96 booster and MC swap theres enough pressure with the MJ block to get the rear brakes locked up. I haven't upgraded the front pads yet. When its time definitely going to black magic pads.

 

Correct. Prematurely........

Link to post
Share on other sites

If I ever get to 33's or higher I'm going to put in an adjustable valve and completely redo the brake lines. The one I pulled out (that gets blocked off) was pretty ate up. Ended up getting a Motive power bleeder. One of the best investments I've made. Works for my 04 WJ and had a separate attachment for my old 83 grand wagoneer.

Link to post
Share on other sites

 

 

I've done 2 Comanches and 1 Cherokee with upgraded boosters.

1 Comanche has rear drums. The other has rear discs as do the Cherokee.

 

On the Cherokee I just swapped out the prop valve guts from a 94 to 98 ZJ.

Works great.

I thought I was going to have to when I did the disk brake conversion but I guess, and I'm no expert, when I did the 96 booster and MC swap theres enough pressure with the MJ block to get the rear brakes locked up. I haven't upgraded the front pads yet. When its time definitely going to black magic pads.

 

Correct. Prematurely........

 

Like I said definitely no expert. My rear only locks up if I slam on them or going downhill from what I can tell but I need to look into how to test it and what to look for on the lock up. If you're right, and probably are, it might be locking up too early. Was my first crack at it.

Link to post
Share on other sites

I'm following this because I just did something similar.  I just wanted to let you know that your pics for step 3 (which came from my build thread, glad they were of use) show the connection at the rear for the #1 hard line, not the #2 hard line.  The #2 hard line is longer, and gone in those pics.  For my bypass I used a YJ prop valve which is plugged at the nose, and has the rear port on the bottom.  So I'm using the #1 hard line, and removed the #2 hard line.  Opposite of what you're doing, if I read right.

 

If you are plugging the bottom port on the MJ distro block, and using the #2 hard line connected to the nose and removing the #1 hard line, I am almost 100% positive you will not need that coupler at the rear.  You should be able to re-bend the #2 hard line and get it to the drop hose.   I am almost positive there's enough length on it to do what you want.  The #2 line is longer in both the front and rear of the MJ.

 

Also, might I add that it's impossible (at least for me) to follow the hard lines from front to back without getting mixed up.  You should start removing the one you want gone at the front and cut it in sections, pulling it out as you go.  That way you can be sure once you get to the rear that you're working with the right line.  I think they crisscross behind the gas tank and skid plate at least once.  I couldn't follow them, so devised the cut until it became clear method.

 

I hope this helps you further develop you plan.

Link to post
Share on other sites

Thanks for the info. I may have crossed up the rear lines following them back, especially since I couldn't really see how they were routed along the gas tank since I have a tank skid that blocked the view or even getting my hand up there. Also the LWB fuel lines are routed a bit differently than the SWB according to the manual. I think I have them right, but will change my post if it's not correct. If anyone with a longbed w/o a gas tank skid can verify the correct routing of the fuel line that comes out of the front snout of the MJ distribution block, please do. 

Link to post
Share on other sites

If I remember correctly I disconnected and plugged the known line to the sensor at the Block then I had my wife tap on the break and I watched which one squirted out fluid I cut the other one off to the fuel tank I later remove the entire line when I remove the fuel tank

Link to post
Share on other sites

Well, I crawled under and pulled the gas tank skid so I could see how the two rear lines run. I've been meaning to pull the skid anyhow since I sure don't need it. What am I going to do? Rip a hole in the tank going over a speed bump at the mall?   :yes:   Anyone need a pristine gas tank skid for a longbed?

 

Back on topic. Yes, the line from the distribution block "snout" does go to the left side port of the load sensing valve body (as SBpunk detailed), NOT the T-fitting that goes to the soft line L & R caliper feed lines. Thanks kryptronic for pointing that out.    :doh: on my part. 

 

So, on to plan B. I will now plug off the block snout port and use the existing lower front port for the rear brake feed line as it is now used. According to Eagle's cutaway, both ports are on the same internal block channel so the output pressures are the same for both ports. Also plugging the snout port will be much easier to get to than plugging the one on the bottom.

Link to post
Share on other sites

So, on to plan B. I will now plug off the block snout port and use the existing lower front port for the rear brake feed line as it is now used. According to Eagle's cutaway, both ports are on the same internal block channel so the output pressures are the same for both ports. Also plugging the snout port will be much easier to get to than plugging the one on the bottom.

 

Your plan B is identical to what I just did with the following exception:  I used a YJ prop valve, and you're blocking the front port of the MJ distro block.  I can't see how blocking one port or the other on that block makes a bit of difference, for what it's worth.

 

I'm interested to see how this goes for you.  I'm having excellent results with the YJ prop valve and the stock D35 with drum brakes.  I am anticipating no problems when I change to ZJ disc breaks during my axle swap.  If you don't like it with the MJ disto block in there, it will be trivial to put in that ZJ prop valve you have later on.  Good luck.  I'm saving my MJ block just in case.

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


×
×
  • Create New...