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  #11  
Old 11-12-2010, 11:31 AM
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Originally Posted by DaveInDenver View Post
They do seize from corrosion and modified suspension is a balancing act, far from an ideal solution.

But still I don't mind having it on mine. Not having to crawl under there every weekend to adjust a valve for Home Depot runs and then again Monday for the commute is nice. It seems to do what it's supposed to in my case even with OME rear springs.
I guess I don't understand why you would want to adjust your front to rear bias every weekend? Every other vehicle in the free world seems to function well without changing the brake bias between offroad, onroad, etc. You normally adjust the proportioning valve to what works well with your vehicle, tire size, typical load, etc then never touch it again.
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  #12  
Old 11-12-2010, 11:33 AM
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or you could just buy it from summit off road, since that's where dave apparently gets them
You can, but what makes Dave's unit nice is he includes all the metric fittings and tubing you see with it. Makes it super easy to install. You can get the Summit unit direct but then you need to piece together the metric adapters, etc.
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  #13  
Old 11-12-2010, 02:33 PM
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So many re-engineers... For those that are not smarter than MIT trained auto engineers the LSPV actually is a smart little device. The easiest way to keep it where it was calibrated is to mark the lever level at stock height then readjust after doing the lift and again after lift settles and your done adding major weight/modifications. Toyota actually has done quite a bit of math and if adjusted properly you will find even brake wear F&R. Adjusting it for more front bias so it feels like better brakes will get you machining rotors often due to warping....just saying....
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  #14  
Old 11-12-2010, 05:32 PM
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So many re-engineers... For those that are not smarter than MIT trained auto engineers the LSPV actually is a smart little device.
I'm sure it was.....when it was working properly.

Now most of them are just a rusted rats nest of tubing.

If they are so wonderful, how come Toyota doesn't put them on every new vehicle they make now?
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Old 11-12-2010, 05:53 PM
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I'm sure it was.....when it was working properly.

Now most of them are just a rusted rats nest of tubing.

If they are so wonderful, how come Toyota doesn't put them on every new vehicle they make now?
They do.....they just tied it into the ABS system along with A-Track.
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  #16  
Old 02-26-2011, 08:27 PM
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After taking the truck up to steamboat and sliding all over the place because the rear tires are not locking up and just keep pushing the truck, I thought I would start looking into this again. I actually took it to a local midas place just to see what they thought and they didn't have any input as to what the problem could be.

I have yet to change out the lspv, but have changed virtually everything else previously including the master cylinder. I did take the arm from the lspv and move it all the way up and all the way down with the truck in drive and my foot on the brake pedal and the rear tires still just keep on spinning. Any thoughts as to what this could be other than the lspv? The guys at midas just said that the rear drums weren't strong enough to stop with the v8 I've got in it, but I seriously doubt that. It's not like I'm accelerating during these tests, just letting it idle and the rear drums will not lock up at all. I guess I'll order that setup from Dave's on the previous page. Seen here: http://www.davezoffroadperformance.c...c.php?f=3&t=52

One question about that setup. What do you do with the bypass line? I have a supply line in, bypass out, and line out to the rear brakes from my valve, but this only has 1 in and 1 out.
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Old 02-26-2011, 08:43 PM
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A few ideas, fwiw.

Any possibility that one or more of the rear cylinders are out of adjustment or frozen? Can you pull one drum on one side off and see the shoes moving at all?

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I did take the arm from the lspv and move it all the way up and all the way down with the truck in drive and my foot on the brake pedal and the rear tires still just keep on spinning.
When you say this did you adjust the lspv at the frame end or the axle end? Not sure if/how much the truck is lifted, but for more than a very small lift it needs to be adjusted at the frame side to get enough adjustment. I'd say you are correct in that the V8 has nothing to do with the braking system unless you are power braking around corners
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  #18  
Old 02-26-2011, 08:49 PM
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Thanks for the input. The shoes are definitely moving, just not enough to provide pressure against the drums, and they are adjusted quite tight against the drums as well.

As for the lspv adjustment, I unbolted it at the axle and held the arm up as far as it would go on the lspv while my buddy had it idling in drive with the brake fully depressed and it made no difference, then moved it down as well and still no difference. I did permanently adjust it as high as it would go at the axle, no adjustment at the frame.

I'm guessing that the valve itself simply isn't providing enough flow through to the rears even when it is maxed out. I just can't think of what else the problem would be other than the master cylinder and that was changed already. Anyone know of a good brake place that would actually know and be able to test it well? I also looked for a brake pressure tester to see how much pressure I'm actually getting back there and I can't find one.
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  #19  
Old 02-26-2011, 09:40 PM
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When you unbolted the axle end of the rod and raised it all the way up, did it max out with in the lspv mechanism or did it hit something on the body? Reason I ask is that due to the linkage of everything, if the lspv was improperly adjusted on the frame side, even raising up the arm all the way may still not redirect enough flow to the rear.

I'm having trouble putting down this thought into words.

Say the valve body on the frame was already mounted too high by 1/4 inch. Axle side adjustment might not make any difference if its out of spec on the body mount? So even maxing out the rod end upwards might not redirect enough flow? Unless maybe the valve is clogged or in some way broken, (or its all rusted out) it may be worth a try to adjust the valve down a 1/4 or 3/8 inch (marking the original spot) and see if that makes a difference, before going and trying to track down a pressure tester ($$$ money on amazon, but maybe someone in the club has one?) Even if you moved it down as far as possible so it was, in theory, as much rear-proportioned as possible, it may give you another test point. If it works, adjust as necessary. If not, than maybe the valve needs replacing??

Just a few more thoughts. Not sure if they are helpful
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  #20  
Old 02-26-2011, 09:52 PM
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When it was unbolted I raised it up all the way to the max of the lspv, there was still room to go up to the body but it would have broken the arm off of the lspv if I moved it up that far I think. When I finally adjusted it permanently I moved the arm up about 2 or so inches. Probably several inches from the maxed out movement I made when it was unbolted, but either way nothing made a difference. I guess to say it another way, I don't think it would matter if the lspv would have been completely removed from the truck during the adjustment. I moved the arm through the full motion of what the lspv allowed and there was no difference.

I absolutely appreciate the thoughts, it helps me think through things more thoroughly. I think at this point I'm hoping that the valve itself is bad being that I have gone through the full range of motion with no difference. Has anyone had one that was completely bad before? Is there something I'm missing, like maybe the rear was not intended to fully lock up? I don't see how that could be possible but maybe I'm missing something. Any thoughts on whether the drums can't handle the output of the v8, or switch to discs? These don't seem likely at all to me either but any thoughts are appreciated.
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