Proportioning valve options

[HOrnbrod]

Perhaps some states might not give a damn about the brake warning light on a 25+ year old vehicle but that's not the point. The point is that you can hurt yourself, your rig, and others if you don't know your brakes are defective. Removing the cat and/or an EGR system are not valid comparisons.

[Knucklehead97]

1 hour ago, HOrnbrod said:

Perhaps some states might not give a damn about the brake warning light on a 25+ year old vehicle but that's not the point. The point is that you can hurt yourself, your rig, and others if you don't know your brakes are defective. Removing the cat and/or an EGR system are not valid comparisons.

Thats my main thing now that I think about it, is safety. Especially if you have 1000+ pounds sometimes in the bed. I just can't decide if i should do a separate sensor for the front lines and the back lines.

[HOrnbrod]

6 minutes ago, Knucklehead97 said:

Thats my main thing now that I think about it, is safety. Especially if you have 1000+ pounds sometimes in the bed. I just can't decide if i should do a separate sensor for the front lines and the back lines.

 

Why not have one sensor for each? Just plumb it in with an additional "T" in each line. It's just a NO switch that applies a ground to the dash brake light when it senses low pressure. You could even parallel the two switch outputs to the existing dash brake light. If/when it illuminates you know there's a pressure problem you'll have to isolate either way.

[kryptronic]

11 minutes ago, Knucklehead97 said:

Thats my main thing now that I think about it, is safety. Especially if you have 1000+ pounds sometimes in the bed. I just can't decide if i should do a separate sensor for the front lines and the back lines.

 

As there's only one indicator light, a second sensor wouldn't tell you anything.  There's a sensor in the MJ distribution block, which to my knowledge doesn't limit braking power to the rear, so using that plus an inline valve on the rear brake line might accomplish what you are looking to do, legally.

[HOrnbrod]

On 5/15/2018 at 9:21 PM, Knucklehead97 said:

And on a side note... could someone tell me what size Speed Bleeders I need for 94 XJ front brakes and a dana 35 in the rear? They seem like they may come in handy for me.

 

SB3824 ( 3/8 x 24) is the correct speed bleeder size for both front and rear.

 

http://www.speedbleeder.com/size.htm

 

[HOrnbrod]

36 minutes ago, kryptronic said:

 

As there's only one indicator light, a second sensor wouldn't tell you anything.  There's a sensor in the MJ distribution block, which to my knowledge doesn't limit braking power to the rear, so using that plus an inline valve on the rear brake line might accomplish what you are looking to do, legally.

 

Depends on whether he uses a YJ prop valve or plumbs the F/R lines independently. If using the YJ valve, just one brake fault light is needed.

[coolwind57]

1 hour ago, HOrnbrod said:

Perhaps some states might not give a damn about the brake warning light on a 25+ year old vehicle but that's not the point. The point is that you can hurt yourself, your rig, and others if you don't know your brakes are defective. Removing the cat and/or an EGR system are not valid comparisons.

 

Removing the cat and/or an EGR system IS a valid comparison as Eagle and my topic of conversation was about legality.  If you go back and read his input, legality was exactly his point.

 

As for safety, you may have valid concerns.  This is something that should be considered by anyone doing such modifications from stock.

[Ωhm]

Brake indicator is OFF with no pressure on the front or the rear brakes. Brake indicator is OFF with equal pressure on the front or the rear brakes. Brake indicator is ON with unequal pressure between the front and the rear brakes. You will need something that senses, both front and rear pressures at the same time, otherwise brake indicator will not work properly.

I'm not sure how a YJ prop valve works. Is there something different?
 

[HOrnbrod]

5 minutes ago, coolwind57 said:

Removing the cat and/or an EGR system IS a valid comparison as Eagle and my topic of conversation was about legality.  If you go back and read his input, legality was exactly his point.

 

[HOrnbrod]

32 minutes ago, Ωhm said:

Brake indicator is OFF with no pressure on the front or the rear brakes. Brake indicator is OFF with equal pressure on the front or the rear brakes. Brake indicator is ON with unequal pressure between the front and the rear brakes. You will need something that senses, both front and rear pressures at the same time, otherwise brake indicator will not work properly.

I'm not sure how a YJ prop valve works. Is there something different?
 

 

It's still a normally open pressure switch that closes when there is a loss of hydraulic pressure. What those pressure thresholds are though, .

[Ωhm]

2 minutes ago, HOrnbrod said:

 

It's still a normally open pressure switch that closes when there is a loss of hydraulic pressure.

What mixes me up, hydraulic pressure all the time means the brakes are on.

[HOrnbrod]

This article explains it pretty well.

 

Pressure Differential Switch

 

There's a lot of stuff going on in the brake combination / proportioning valve. 

[Ωhm]

Thanks. Let me buy a round. Still need time to sort this one out.

[HOrnbrod]

2 minutes ago, Ωhm said:

Thanks. Let me buy a round. Still need time to sort this one out.

 

Me too.  

[Eagle]

38 minutes ago, HOrnbrod said:

 

It's still a normally open pressure switch that closes when there is a loss of hydraulic pressure. What those pressure thresholds are though, .

 

What are we discussing? The factory warning system in the XJ, MJ, and ZJ (don't know about the YJ, but probably the same) isn't a pressure switch at all. It's a mechanical plunger switch that's normally open, and closers when the plunger is depressed (which happens to be UP as the switch is installed). The pressure sensing component is the sliding shuttle valve in the top of the distribution block. Take a look at the cutawy photos I've posted in other threads to see how it works.

[kryptronic]

2 hours ago, HOrnbrod said:

 

Depends on whether he uses a YJ prop valve or plumbs the F/R lines independently. If using the YJ valve, just one brake fault light is needed.

 

As I read this thread, it looks like at this point he's looking to get full pressure to the rear, and limit it with an inline valve.  The YJ prop valve won't work for that (limits rear pressure) so he'd need to use an MJ distribution block.  I was recommending the MJ block because it fills his requirements.  I didn't think he wanted to add a second warning light, bur I could have missed that.

[HOrnbrod]

1 hour ago, Eagle said:

 

What are we discussing? The factory warning system in the XJ, MJ, and ZJ (don't know about the YJ, but probably the same) isn't a pressure switch at all. It's a mechanical plunger switch that's normally open, and closers when the plunger is depressed (which happens to be UP as the switch is installed). The pressure sensing component is the sliding shuttle valve in the top of the distribution block. Take a look at the cutawy photos I've posted in other threads to see how it works.

Sigh -  don't care anymore..

 

 

 

[kryptronic]

1 hour ago, Ωhm said:

I'm not sure how a YJ prop valve works. Is there something different?
 

 

YJ prop valves work exactly the same way as those found in XJ/ZJ vehicles, with each having a different bias for the rear.  They look the same, plug and go.

[Knucklehead97]

I'm just getting opinions and everything on multiple options for the brake system. Including the idea of completely deleting the distribution block and adding my own switches for the brakes. I'm MOST likely going to keep the distro block, bypass/delete the LSV (Hornbrod, it's yours if you want it!) add an adjustable valve for the rear, and see how I feel about that. My only problem with the distribution block is that the holes are only .050". But running 2 aftermarket switches and completely deleting the block is seeming like more work than I feel like doing on brakes currently. SO if it was you adding an adjustable valve for the rear lines, would you install it before or after the distribution block? And just to be sure, the distribution DOES NOT limit rear brakes at all compared to the front ones once you bypass the LSV, correct?

[Jeep Driver]

All I did was plug the front port, eliminate the LSV, rear discs. 

 

Perfect. Don't know what everyone else is running in circles about?

 

 

Once I install the Wilwoods...........? we'll see. 

[Knucklehead97]

9 minutes ago, Jeep Driver said:

All I did was plug the front port, eliminate the LSV, rear discs. 

 

Perfect. Don't know what everyone else is running in circles about?

 

 

Once I install the Wilwoods...........? we'll see. 

I'm just not going to rear discs anytime soon. WhenI install my 8.25 I already have brand new drum brakes on it haha.

[HOrnbrod]

1 hour ago, Knucklehead97 said:

I'm MOST likely going to keep the distro block, bypass/delete the LSV (Hornbrod, it's yours if you want it!)

 

I'll take it. Let me know when you're ready.