Adjustable rear proportioning valves--tips for location

[coolwind57]

Getting ready to redo rear brake lines.  Load adjusting valve had been deleted.  i want to run an adjustable proportioning valve.  

 

What's a good location?  Dash mount?  Underhood mount?  What has worked for you guys that have had done this?  

[Crash]

IIRC, most are just installed in the prop block under hood. 

[coolwind57]

16 hours ago, Crash said:

IIRC, most are just installed in the prop block under hood. 

I get it, but sounds boring to me.  Plus, you have to pop your hood to adjust after loading your bed.

 

I'm thinking dash mount or even back along the rear bumper somewhere.  Just make your adjustment when you're done loading your truck.  Anyone done anything creative?

[Jeep Driver]

I don't think it's going to work the way you think it will. That valve is not a spigot you turn on and off 6 times per day. 

 

Have you gone to rear disks yet?

[coolwind57]

5 hours ago, Jeep Driver said:

I don't think it's going to work the way you think it will. That valve is not a spigot you turn on and off 6 times per day. 

 

Have you gone to rear disks yet?

What??  Six times per day?!

 

I will be loading my truck with firewood maybe 4-5 times per year.  I may haul furniture once next year.  I get a load of aged horse manure each Spring.  I never envisioned an adjustable "spigot" that I use 6 times per day.  Just thought it'd be cool to have the controls maybe in the cab and not have to pop the hood--even more so if I am experiencing lockup while I'm traveling.   My use will likely be more like 6-times per year.  I have no interest in rear discs, btw.  I hear complaints about MJ brakes from guys here, but I really have no issue with my brakes. 

 

I just wanted to see some creativity on where guys were mounting their adj pro valves.  My truck is apart and I'll be running new brakes lines this weekend.

 

[HOrnbrod]

I've only seen them under the hood or under the car on an existing brake line. Put it anywhere else and you will have to run additional brake lines to the new location then back. Then you have bleed it all. Hardly worth it IMO for something you might adjust 4-5 times a year.

[Skorpyo]

I'm planning to put mine near the rear along the frame rail where I put the union from the old brake lines to the new brake lines. I deleted the LSV when I put in an 8.8 but mainly so I would have room for a full size spare. That and it wasn't hooked up anyways.

I'm also planning to put a shield piece under it so that it doesn't get covered in road spray and get ruined.

[DirtyComanche]

Most guys who adjust them regularly put them within reach of the driver.  Which means you have to route brake fluid into the cab, not a big deal but some jurisdictions frown on it.

 

IMHO the factory setup is the actual intelligent way to do it...  It's not like the MJ was the only truck equipped with a load (height) sensing valve.  Most of the issue is that they are no longer functioning on a vehicle this old, or that the vehicle has been modified and it's not adjusted at all well because of that.

 

Edit, I will fully admit it would be nice to have mine back and functioning.  It was deleted before I got the truck.

[coolwind57]

4 hours ago, HOrnbrod said:

I've only seen them under the hood or under the car on an existing brake line. Put it anywhere else and you will have to run additional brake lines to the new location then back. Then you have bleed it all. Hardly worth it IMO for something you might adjust 4-5 times a year.

 

I'm envisioning running a new brake line from front proportioning block to my dash and into the "IN" port of the adjustable proportioning valve (APV).  Next, I install a line from the "OUT" port of the APV.  This line then simply goes and ends at the rear brake hose that feeds the two rear brakes.  Seems very simple to me unless I'm missing something critical here.  I'm not following you about running "additional brake lines...and back" and difficulty with bleeding.  I'm seeing a very simple straight, one-direction run here. 

 

Am I oversimplifying or something HOrnbrod?  

[DirtyComanche]

9 minutes ago, coolwind57 said:

 

I'm envisioning running a new brake line from front proportioning block to my dash and into the "IN" port of the adjustable proportioning valve (APV).  Next, I install a line from the "OUT" port of the APV.  This line then simply goes and ends at the rear brake hose that feeds the two rear brakes.  Seems very simple to me unless I'm missing something critical here.  I'm not following you about running "additional brake lines...and back" and difficulty with bleeding.  I'm seeing a very simple straight, one-direction run here. 

 

 

That's how it's done if you wish to adjust it on the fly.

 

Just make sure you route the lines nicely and use a good grommet on the firewall so nothing chafes.

 

This will not automatically give you full pressure in the event of a front system brake failure, and that's about the only downside.

 

Make sure the valve you buy is stiff enough, detented, locking, etc, that it will not be accidentally bumped or vibrate out of the intended position.

[HOrnbrod]

Yep, you're running new lines to plumb your new in-cab APV in series with the rear brake supply line. That sounds running additional brake lines to me.

 

Me, I'd just stick the APV under the hood near the distribution block. But it's your truck mate - go for it. 

[coolwind57]

1 hour ago, DirtyComanche said:

 

That's how it's done if you wish to adjust it on the fly.

 

Just make sure you route the lines nicely and use a good grommet on the firewall so nothing chafes.

 

This will not automatically give you full pressure in the event of a front system brake failure, and that's about the only downside.

 

Make sure the valve you buy is stiff enough, detented, locking, etc, that it will not be accidentally bumped or vibrate out of the intended position.

 

Good stuff.  I'm aware of losing my full-pressure-to-the-rear in case of front brake failure.  I've already lost that feature when the PO deleted the height-sensing valve.  The risk is very minimal and acceptable in my eyes.  Good advice.  I'll get a quality APV and mount it well.  

1 hour ago, HOrnbrod said:

Yep, you're running new lines to plumb your new in-cab APV in series with the rear brake supply line. That sounds running additional brake lines to me.

Man, I'm laughing because we're just not connecting here.  It could be my tiny pea-brain, man.  I'm certainly not frustrated with the conversation and I really hope you're not becoming frustrated with me.  I'm just smiling because I am hoping that I'm not missing something stupidly simple here and I'm going to end up looking like a jackass.  i admire your knowledge HOrnbrod, and have learned a TON from you since I've been on board these last two Months.  I'll throw this at you and we'll shoot this poor horse and you and I can be done with this topic. 

 

There is no "in series".  It's a 1989 MJ dual rear brake line system being replaced with an all new single brake line to the rear.   It just happens to have an APV installed in the middle.

 

I'm removing both of my REAR rusty old brake lines that come out of front proportioning block.  Tossing them in the trash.  Cleaning up my frame rail where the two old lines were and painting.  

 

Then I'm blocking the "emergency-oh-hell-I lost-my-front-brakes" port of the front proportioning block with a plug (at the block).  I then run a single brand new rigid brake line from proportioning block into my cab and into the "IN"  port of my new APV.  I run the second half from the APV's "OUT" port and to the rear brake hose that distributes fluid to each of the two rear brakes.   

1 hour ago, HOrnbrod said:

...you're running new lines...

 

No, I'm running a new line- -"line" without the "s" on the end.  I think I just didn't make it clear that I was removing the two stock rear brake lines and replacing with one.

[HOrnbrod]

It's simple. Your very first post stated " Load adjusting valve had been deleted". Like a dumbass I assumed all the rusty original rear brake lines were already removed and you had the single line run done w/o any proportioning, as is commonly done by some folks on this forum. We're okay.

 

I still wouldn't want any brake lines in my cab, but that's your choice mate.

[Jeep Driver]

9 hours ago, coolwind57 said:

What??  Six times per day?!

 

I will be loading my truck with firewood maybe 4-5 times per year.  I may haul furniture once next year.  I get a load of aged horse manure each Spring.  I never envisioned an adjustable "spigot" that I use 6 times per day.  Just thought it'd be cool to have the controls maybe in the cab and not have to pop the hood--even more so if I am experiencing lockup while I'm traveling.   My use will likely be more like 6-times per year.  I have no interest in rear discs, btw.  I hear complaints about MJ brakes from guys here, but I really have no issue with my brakes. 

 

I just wanted to see some creativity on where guys were mounting their adj pro valves.  My truck is apart and I'll be running new brakes lines this weekend.

 

Every kit, every custom hot rod I've seen with an adjustable prop valve is as shown in the pic, not on the dash,  not underneath in the frame rail (shield or no shield). 

 

With fresh front and rear brakes, drums adjusted, bias is set at the valve, once you are happy with it, that's it. 

 

It's not a height-sensing valve, it's not a replacement for one, it's not meant to be used as one. 

 

I'll also mention, if you are retaining drums, when drum braking wanes, it's time to inspect and adjust or replace, if you are constantly increasing pressure, changing pressure, how will you know when it's time for service before failure?

 

[Ataki]

Mine is done like in the pic above, in place of the factory distribution block. Same valve even. A note- This valve will not keep full pressure to the fronts if you lose pressure in the rear. When I blew a wheel cylinder, even with the bias set completely to the front, I was still losing fluid at the rear, and had barely enough pedal to stop the truck.

[Tj1]

Threw mine where the ebrake release handle was. Couple quick bends of some lines in the cab and out on the top of the trans tunnel. I like the adjustability on the fly right next to my knee. The prop valve was cheap too

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[coolwind57]

7 hours ago, Jeep Driver said:

With fresh front and rear brakes, drums adjusted, bias is set at the valve, once you are happy with it, that's it. 

 

 

If you have no height sensing valve, as I don't have, what about load weight variations in your bed?

 

Based upon previous posts in the comancheclub forum, I saw guys advising that the use of an adjustable proportioning valve may be necessary upon a delete of the load sensing valve. 

 

This note from our friend HOrnbrod:

"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."

 

From Cruiser54:

"Ditch both the distro valve and load sensing valve. T the front lines together and use an adjustable proportioning valve for the rear.  The best combo. " 

And:

"Ditch the distro valve. T the front brake lines together. As for the rear, ditch the load sensing valve and use an adjustable proportioning valve in the engine bay.  Works way better than anything else. I have done this both ways and documented the differences."

 

Since the PO had already deleted my load sensing valve, I have no control of my rear brakes locking up when I have a heavy load.  You can set bias with an APV of course, but is it possible with one setting of the APV to acquire that perfect sweet spot of ideal braking performance when your bed is empty versus when your bed is loaded down?

 

Guys, I have my truck apart right now.  I thought since the PO had deleted my load sensing valve and had half-assed the two brakes lines going back there, that I'd go ahead and pull both rusty lines out and start over.  And use a new single line.  That topic I reference above got me thinking. And today is the day that I begin ripping my old crappy lines out.  

 

8 hours ago, Jeep Driver said:

It's not a height-sensing valve, it's not a replacement for one, it's not meant to be used as one. 

Why not? 

 

If APVs are adjustable, as their name implies, then why not have the capability of reaching over and adjusting a dial if you're loaded down and approach a stop light and notice that you're rear brakes are locking up?

 

I certainly don't want that proportioning valve that Jeep Driver has in that picture above:

8 hours ago, Ataki said:

This valve will not keep full pressure to the fronts if you lose pressure in the rear. When I blew a wheel cylinder, even with the bias set completely to the front, I was still losing fluid at the rear, and had barely enough pedal to stop the truck.

 

I think I'll go with Cruiser54 on this one.  I'll dump the entire proportioning block, install an in-line APV for the new rear line.  This makes the most sense to me.  After it's all done, I may set those rear brakes one time and never have a problem.  But at least I have the option to adjust if needed.

 

I appreciate everyone sharing their experiences and ideas.  That's why I love this place.  Learned a ton from you guys.  Some have strong egos, and you'll sometimes see posts where guys really come off in their writing style as "inflaming" and cocky or rude.  Or annoying.  I hope I never come off as any of those. 

 

 

 

 

[coolwind57]

5 minutes ago, Tj1 said:

Threw mine where the ebrake release handle was. Couple quick bends of some lines in the cab and out on the top of the trans tunnel. I like the adjustability on the fly right next to my knee. The prop valve was cheap too

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[coolwind57]

Exactly what I was looking for in this post, TJ1.  Thanks!

[Jeep Driver]

OK, it's your truck, you don't need anyone's permission to do what you want. 

 

 

I will say though........there seems to be a fascination with brake valving here.............I don't get that. 

 

99% of the trucks on the road have no HSV. 

 

I have no HSV nor an APV, no valving. If you consider stock braking 'good', mine are good. Empty, pulling a trailer down the mountain side, hauling heavy materials,  a DD of 5 years as a work truck.......never a problem with braking bias. 

If your goal is improved rear braking, go with discs. 

 

My comments in the previous post stand. 

[HOrnbrod]

1 hour ago, Tj1 said:

Threw mine where the ebrake release handle was.

 

Do you still have an e-brake?

[Tj1]

 
Do you still have a e-brake?

The e brake cable was rotted out under the bed and at the wheels. I pulled the release handle and foot kicker. Its a trail toy and won't see any pavement. I keep rubber tire chock in the bed I can throw under it when parked on a hill.

Still have the foot kicker if any one needs one ;)

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[DirtyComanche]

5 hours ago, Jeep Driver said:

99% of the trucks on the road have no HSV.

 

They were popular through the 80s to late 90s on Ford, Dodge, GM, Toyota, Mitsubishi, and Mercedez trucks...  Plus the MJ.  Not to mention many older semi trucks used a similar system.

 

With the advent of 4 wheel ABS systems that actually worked, it's more or less an obsolete system.

[cruiser54]

As for location and adjusting, every time I've used an APV, I adjusted it once or twice and then never needed to adjust it again for different conditions. 

[coolwind57]

I'm going to put this on my build thread as well, but for future searchers of this topic I thought I'd share the choice I made in renovating my stock brake system to include a APV.

 

 DISCLAIMER:  i'm speaking in simple, general terms.  I'm no engineer.  One can likely really dig in and nit-pick my words, philosophies, and techniques.  I'll probably just ignore you if that's the case.  I'm proudly open-minded and naturally inquisitive with little-to-no inflated ego.  I'm cool with constructive input and I'm cool with what I did on this project.  There's a million ways to skin a cat.  I nope what I chose helps to spark ideas of how others may want to tackle this job.   

 

 

MY SITUATION:  Original front disc and rear drums.  Height Sensing Valve (HSV) half-assed deleted by PO.  Still had 2 old crappy brakes lines running to rear.  Acceptable brakes as a whole, but redoing it all because I already have the truck apart anyway and didn't like the rusty, brittle looks of things.  Plan is to renovate brake system for added reliability and maybe even get some added performance as a bonus.    

 

I chose to start things off by trying Cruiser54's front Proportional Valve (PV) trash and replace procedure.  This seemed logical as a way of simplifying things and perhaps improving front brake performance..  Plus He's got real-world experience doing this and it has worked for him multiple times. 

 

I figured at least to me, that the MJ PV was designed to work a system that included the additional second brake line to the rear (to be used in cases of front brake failure) AND a system including a well-working HSV.  Since I now have neither, the MJ PV is no longer being used exactly according to its design with those two aspects missing.   

 

The MJ PV meters the front brakes down considerably after the brake line run into it from the master cylinder.  Just look up some of Cruiser54's pictures of those tiny little orifices in there.  Remove entire PV and then T-off to your front calipers, using an inverted flare brass T.  You should get better braking because the small orifices of the prop valve to the front brakes are eliminated.  You're now running near-full opening size of the hard brake lines that are coming off direct from the master cylinder.  Makes sense to me so I did it:

 

and here's a view from side/bottomp:

 

Now technically I should experience slightly better front brake because I have larger interior diameters running from the master cylinder on through to the calipers.  

 

Because I am eliminating some front and rear "bottle-necking" I used to have at the now-removed PV, I agree with many others here that an Adjustable Proportioning Valve  (APV) may be a good idea.  This should eliminate any rear brake lockup that I may experience if I am running a heavy payload.   The original intent of this thread was to see where other guys were mounting their APVs.  I ended up deciding on mounting mine under the hood after all.  Even though TJ1 had a cool location on his rig, I ultimately sided with HOrnbrod's opinion of not having brake lines inside my cab.  Mounting near the rear of the bed would likely affect longevity and stable function due to full exposure to elements.  

 

I  completely eliminated my two old hard rear brake lines and ran a new single line back there the the axle.  So here's where I ended up mounting my APV:

      

 

I chose the Speedway APV because it is compact and appears to be simple and tough.  Another cool feature is that it allows for full shut down of fluid to the rears, which can possibly come in handy when working on your brakes.  

 

REMINDER:  If you've read much on the topic of HSV deleting/PV deleting/running a single line to your rears, keep in mind that you'll lose that safety feature that allows full braking to the rears in cases of front brake failure.  

 

I hope to have my truck back together within a week or so and I'm anxious to see how well it works for me.