I know what it does and where it's located. Has anyone here taken one apart? What are the steps in taking it apart? I can see a C-clip...if I take that off will the internals come out without any other pieces needing to be removed? I'm guessing that my LSPV is gummed up in the max position.


I had some problems with pressure at the rear brakes...there wasn't any. Got a new master cylinder and bench bled it and installed it. Bled the system out including the LSPV. When bleeding the rear brakes...fluid came out very slow out of the rear bleeders. Got a semi okay pedal but not anything close to firm or bottomed out on the pedal. Checked the rear brakes again...no stopping. The test I used was to jack the rear end up so the rear tires were off the ground and rotate the tires. Stomp on the brake...the tires kept rotating. <img src="/forums/images/graemlins/frown.gif" alt="" />

When I took the rod and rubber boot off the the LSPV, it seemed to be locked in the max position. I rotated the guides and then banged the crap out of LSPV with an "attitude adjuster" tool. Tried the pedal again...it finally bottomed out. Bled the LSPV and then the rears. Got a ton of air out of it and finally got a firm pedal...and the rear tires finally stopped when I pressed on the brake! I'm guessing I coaxed the air out of the LSPV... <img src="/forums/images/graemlins/smile.gif" alt="" />

Here's the piccie of the LSPV with the rod and rubber boot off.


If I install the rod in it's normal position, the shaft of the LSPV doesn't even touch the rod...which leads me to believe that it's stuck in the up position and should extend further down. So I'm asking fer some step by step assistance to take this puppy apart so I can be assured that it will work correctly. That or go by a parts yard and source one there fer me to practice on before I go live with the one on my truck.

Any assistance is greatly appreciated! <img src="/forums/images/graemlins/smile.gif" alt="" />

Think about how it works... When the bed is sitting lower, the valve opens more to give more pressure to the rear brakes.

If your pedal is firm maybe you can take the rod off and adjust it manually to see if it works. Should be pretty easy if you have a gravel road to play on. Maybe you will find that it works and you just need to adjust the adjuster length.

It is difficult to eyeball and see if the rod is bent because it is not a straight rod. If it is bent I bet the paint will be cracking and falling off of it though.

When I cycled the rod to the bottom of the bed, the shaft contacted the valve shaft at that time and it didn't even touch the rod either. I checked the rod over and it isn't bent.

When you took yer LSPV rubber boot off, how much of the valve shaft was showing? I can take an 3/8" drive extension and put it between the guides and the valve shaft barely touches that. <img src="/forums/images/graemlins/frown.gif" alt="" /> That's why I'm thinking the valve is stuck

Does anyone know if the LSPV shaft is supposed to protrude down when you step on the pedal? I didn't think about that part when I was stepping on the pedal...couldn't run back fast enough to see if it did or not. <img src="/forums/images/graemlins/smile.gif" alt="" /> <img src="/forums/images/graemlins/lol.gif" alt="" />

The FSM manual I have for a 97 doesn't show any disassembly info or parts diagram for it. You might check with the dealership and see if they make a repair kit for it before pulling it apart in case there are somes seals, etc. that need replacing.

It's officially a "non-servicable part" that comes apart readily enough with a wrench and a vice. Yes, it gets sludged up internally and rusted up externally. By all means, disasemble it and clean it up.

How many parts will I be looking at?
Can it be done with it still bolted in place?
I was able to put a 1-3/16" wrench on it and it was a little big...so I'll have to find the metric equivalent that's a size smaller.
What's the C-clip holding then? Can it be disassembled and cleaned that way instead of cracking it open on the retaining nut?

You wouldn't be able to service it well while mounted on the truck. You need to be able to hold it, tilt it, admire it and such. Sorta like trying to rebuild a master cylinder while on the truck. Technically, it can be done, but you do yourself no favors by trying it.

Don't remember the various wrench sizes required off the top of my head, but I can say with certainty it's metric. Though in the larger sizes you can often make do with inches.

Don't remember the exact count of the various components, but it's really only a few. A dozen at the most. It's not daunting once you remove it and open it up.

Guess I'll have to find a used one and document the parts in it then. Not willing to crack the only one I have on the truck as I have lots of miles to travel before I'm done and don't want to be stranded cause I screwed up the rebuild. <img src="/forums/images/graemlins/wink.gif" alt="" />

Seeing that many people have already had problems with their LSPV...some have ripped theirs out while other have put in the manual adjustable ones with adapters and such. Not sure I want to lean that way.

Anyone have one that they are willing to loan/part with so I can see how they are put together? Or if yer willing to document (with piccies) the rebuild and inspection on here, I'd really appreciate it. <img src="/forums/images/graemlins/smile.gif" alt="" />

I would bet it is the same one that is in the mini trucks and they are everywhere in the junk yards.