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My LPSV mod

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Old 04-26-2011, 06:28 PM
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My LPSV mod

There's a lot of people on here raised their suspension and found out that their brakes are not the same. This is because the rear LPS valve is limiting the brake pressure going to the rear wheel. You can add a bracket to the end of the arm to raise the arm so it's back to stock level or do what I did.

I use a turnbuckles like this one... http://www.lowes.com/pd_22225-1277-M...%3Dturnbuckles . With a metal plate with two holes, I use one to fasten it to the frame the other for the bolt of the same thread. I added a nut in between so the bolt won't move when you turn the turnbuckle.
I cut the arm of the LPSV and insert it in to the loop. You make the adjustment by turning it.
Anyway, I will do a write up later but here's the pic of it...sorry it's dirty cause I did this a while ago.

[IMG][/IMG]
Old 04-27-2011, 03:18 AM
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great idea! i plan to eliminate my LSPV all together...but until then may have to do this mod. Lift my truck last sat and now my brakes aren't so good
Old 04-27-2011, 07:45 AM
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A ziptie will do the same exact thing and will be a lot quicker than what you did.

Old 04-27-2011, 08:00 AM
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Mine are both zip tied.
Old 04-27-2011, 08:03 AM
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this is my recent mod 2" extended. So far it seem ok.
Personally I didn't like the idea of just defeating the purposed of the LSPV as least not when mine is a DD.


Last edited by xxxtreme22r; 04-27-2011 at 08:04 AM.
Old 04-27-2011, 08:50 AM
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I can adjust this when I tow a trailer or carry heavy load. You can tighten the zip tie once. This is more precised way of adjustment. You don't have to move much to make a difference.
Old 04-27-2011, 10:35 AM
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Bracket method requires no adjustment as it is automatically adjusted.
Old 04-27-2011, 11:48 AM
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Hmmm. Where does the ziptie-ing take place exactly? Could someone post up a pic? After my Chevy install, my LSPV was at first leaking, and now my junkyard replacement is definitely affecting rear wheel braking. The new downtravel it has to deal with makes me a little nervous too...
Old 04-27-2011, 12:26 PM
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4bangercraig, I see your concern. When your tire foces the arm to go down, there's almost no brakes going to the rear...it's fine if you don't need to stop...when you do, you don't have it though. My mod will address that problem also.
Old 04-27-2011, 12:32 PM
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Originally Posted by xxxtreme22r
Bracket method requires no adjustment as it is automatically adjusted.
I think it would depend on the type of lift. Considering that the LSPV is setup for the stock spring rate, lift springs + bracket would not take into account the difference in spring rate. Not to mention that if you carry heavy loads the shackles are supposed to be mounted further back (this is what I've gleaned from the install guides, they all say the shackle mounts have to be in a different place for heavy load-carrying) to keep them from bottoming out, which would have an affect on the LSPV's operation, as lighter loads on springs not mounted this way would press down as far as heavier loads on springs mounted that way. Though I guess you could adjust the bracket accordingly.

If someone uses blocks (dear god why) and the bracket then the operation of the LSPV would remain the same.

I prefer the manual bias valve because you can keep the pressure constant for a given load, whereas suspension cycling would cause the brake pressure to fluctuate with the LSPV.

Last edited by Magnusian; 04-27-2011 at 12:41 PM.
Old 04-27-2011, 12:54 PM
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This is a concern?..lol.. I havent gone extreme wheeling since but my rear brakes exist not. I had a small brake leak in the rear so I crawled under and found the line was leaking at just before where it goes over the fuel tank (from back). cut and repaired... when I was routing and bending tubing to go to the portioning valve another of the three lines busted... I was a bit frustrated. I removed the rear brake line at the master cylinder and plugged it with an appropriate bolt. so I have no rear brakes. I am a carpenter and OFTEN have HEAVY loads in. yet haven't had any bad problems braking (scared as heck in the rain though, even though no probs in the rasin yet, scared ya know) . I have the line and the fittings and repair couplings just not the motivation as I have engine issues. Also my LSPV rod is bent in a few differant directions, is this correct?.. I will get pics asap.
Old 04-27-2011, 12:56 PM
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lspv is not fun either

Last edited by DIRT CLOD; 04-27-2011 at 01:00 PM.
Old 04-27-2011, 02:41 PM
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Dirt Clod, That's dangerous man. I hope you don't take on any passengers with your truck in that condition. I can tell right away when I tow something and haven't adjust the LPSV. It just took longer to stop.
Old 04-27-2011, 04:42 PM
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I thought there are passenger cars with no rear brakes these days. You gotta remember, your rear brakes actually account for a tiny fraction of your stopping power because when you slow down the weight of the vehicle shifts forward. Ever noticed how when a car is coming to a stop the front-end dips?
Old 04-27-2011, 04:57 PM
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I just un bolted mine when I swapped axles and wired it to my frame
Old 04-27-2011, 05:34 PM
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Originally Posted by DIRT CLOD
This is a concern?..lol.. I havent gone extreme wheeling since but my rear brakes exist not. I had a small brake leak in the rear so I crawled under and found the line was leaking at just before where it goes over the fuel tank (from back). cut and repaired... when I was routing and bending tubing to go to the portioning valve another of the three lines busted... I was a bit frustrated. I removed the rear brake line at the master cylinder and plugged it with an appropriate bolt. so I have no rear brakes. I am a carpenter and OFTEN have HEAVY loads in. yet haven't had any bad problems braking (scared as heck in the rain though, even though no probs in the rasin yet, scared ya know) . I have the line and the fittings and repair couplings just not the motivation as I have engine issues. Also my LSPV rod is bent in a few differant directions, is this correct?.. I will get pics asap.
Take this truck off the road. You had better have some damned good insurance. get into an accident with your truck set up like this and you will most likely be wholly liable...
Old 04-27-2011, 06:31 PM
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So seems like your two options are 1- Disconnect the arm and hold it in a place where the vehicle thinks it's always under load, or 2- Add a bracket to compensate for your lift.
For someone like me with Chevy's, seems like the disconnect might be better as the different spring rate, length, rednecked shackle setup, downtravel, etc. will be messing up the LSPV's ability to do supply braking power to the rear. Sounds like this could very quickly become a concern in the rocks operating off-camber.
Seems like if you're running an add-a-leaf or other lift using stock or stock-length springs the bracket might be the way to go as it preserves the original function of the LSPV.
Old 04-27-2011, 06:58 PM
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theres a kit that allows you to delete the LSPV and put a manual valve either in the place of it or right beside the master cylinder. that is the BEST option, if you arent cheap like me lol
Old 04-27-2011, 09:41 PM
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Originally Posted by DIRT CLOD
This is a concern?..lol.. I havent gone extreme wheeling since but my rear brakes exist not. I had a small brake leak in the rear so I crawled under and found the line was leaking at just before where it goes over the fuel tank (from back). cut and repaired... when I was routing and bending tubing to go to the portioning valve another of the three lines busted... I was a bit frustrated. I removed the rear brake line at the master cylinder and plugged it with an appropriate bolt. so I have no rear brakes. I am a carpenter and OFTEN have HEAVY loads in. yet haven't had any bad problems braking (scared as heck in the rain though, even though no probs in the rasin yet, scared ya know) . I have the line and the fittings and repair couplings just not the motivation as I have engine issues. Also my LSPV rod is bent in a few differant directions, is this correct?.. I will get pics asap.
That right there is the dumbest and most careless thing i've ever heard of. Most cars/trucks the brake biasing is 60 percent front 40 percent rear. You are driving around on a fraction of your braking power. Not only are you putting excesive wear on the front brakes and suspension. You are putting everyone who drives infront of you at major risk. Way to be a danger on the road to everyone else.
Old 04-28-2011, 12:52 AM
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Originally Posted by sebastianholmes
theres a kit that allows you to delete the LSPV and put a manual valve either in the place of it or right beside the master cylinder. that is the BEST option, if you arent cheap like me lol
this mounts at the LSPV location:

$80 from Dave's Off road:
http://www.davezoffroadperformance.c...ion-valve.html

or you could go this route from Front range Off Road
http://frontrangeoffroadfab.com/nfos...87f97c6a1ab4c0
it mounts at the master cylinder:

personally I like the mount at the master cylinder as the proportioning valve is not exposed where some idiot could mess with it....


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