Truck is a 1990 extended cab with 22re. My load sensing spring has failed. Anybody have any experience with this? I don't really know how it works.I'm just going to re-assemble it as it was, with a replacement spring from a wrecker. At least temporarily. Parts are still available, but are super expensive from the dealer. Any parts suppliers out of the U.S carry this?
Load sensing spring (1 Viewer)
- Thread starter jgranthevagrant
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Do you mean the arm for the LSPV? Goes from axle to frame. Really only useful for large loads on pavement, zero value in the dirt. If it's the valve that failed it can/should be replaced with an aftermarket adjustable from someplace like Summit. If you do replace it put the new one under the hood next to the master cylinder and bypass the one on the frame.
ntsqd
technerd
If you're at or near stock ride height with close to stock tire size the LSPV is actually the better bet. It's like having someone under the hood/truck dialing that knob on the wilwood part back and forth as the loading in the truck changes.
That said, with a shell on the bed, level on OME fronts and GM 63's in the rear, rolling on 33-10.50's I found that I could run it with the arm fully up (heaviest "load"). Lot less work to build this little device & cut the arm off:
That said, with a shell on the bed, level on OME fronts and GM 63's in the rear, rolling on 33-10.50's I found that I could run it with the arm fully up (heaviest "load"). Lot less work to build this little device & cut the arm off:
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- Thread starter
- #8
Whoa. Looks like I will have to take a closer look and make a plan. The spring actually broke at the axle end. Valve looks fine, without looking too closely. I carry a fair amount of weight: camp gear, water, wood, tools, chainsaw, canopy (cap), plus additional gear depending on activity, bikes, skis, etc. Truck is on OME heavy springs and 32.5 tires for now. I will look at the LSPV on the weekend. Might just roughly put it back together until I decide on the plan. there is no way it was working for who knows how long until the spring actually fell away from the boot. I need to pay a bit of attention to appearance, in case inspectors ever look at it.
ntsqd
technerd
Prior to making that bracket I ran with mine pulled up to the cross-member. Used magnesium filler rod to save weight while holding it up there.
I made it adjustable and it didn't need to be. Could have simply slotted the mounting bolt holes, adjusted it fully up, and tightened the nuts. I'll bet it you get one on there soon painted the same color as everything around it, get some trail miles on it, that it will "disappear" and no one will notice it.
I made it adjustable and it didn't need to be. Could have simply slotted the mounting bolt holes, adjusted it fully up, and tightened the nuts. I'll bet it you get one on there soon painted the same color as everything around it, get some trail miles on it, that it will "disappear" and no one will notice it.
I've pulled several of those LSPV thingys off and pulled them apart, and found them full of crud, the plunger stuck fast, so they haven't worked in years. When they were still available, they were ridiculously expensive to replace, but I'd bet they are NLA now (not bothering to check)
ntsqd
technerd
I've got to wonder how many have never been bled.
- Thread starter
- #13
Well, the boot kit and spring kit were $160 and $250 respectively (Canadian Peso), but were still available. vancouver and California warehouses. I didn't even ever check it until the bar fell off one day. I pulled everything off while replacing a burst brake line. valve looks ok, nice and clean, but who knows if it works. The inspection worry is only if you get sent for a real one, where they look at everything, and you fail for torn seats.
- Thread starter
- #14
Threw it back together on Sunday. Tore the old boots putting them back on. pretty expected. I suspect the push rod or whatever it is called in the LSPV should move? It seemed pretty permanently stuck, so I doubt if the valve is functioning. I'm just trying to get brakes back to as good as they were before I broke a line in the fall. I will look at proportioning valve options later in the spring.
on page 4 or 5 there is a pn for a t fitting that I used to replace my lspv, I think it was 20 or so for the fitting Write-up: Toss the LSPV and install a manual proportioning valve
ntsqd
technerd
My understanding is that one of the lines at the LSPV is from the Front brakes. If that is correct and you T them together you create one or two problems.
First is that you have now plumbed around the safety aspect of a tandem MC. Without the T should one circuit fail (leak, etc.) the other circuit is unaffected. With the T in place they're all common hydraulically, if one circuit fails the other can't build any pressure either.
You also by-pass any front mounted p-valve that you may have added.
The way it was done in the past is to plug the front line at the T on the RS frame rail near the RF tire and use a coupler at the rear to connect the two rear brake lines.
First is that you have now plumbed around the safety aspect of a tandem MC. Without the T should one circuit fail (leak, etc.) the other circuit is unaffected. With the T in place they're all common hydraulically, if one circuit fails the other can't build any pressure either.
You also by-pass any front mounted p-valve that you may have added.
The way it was done in the past is to plug the front line at the T on the RS frame rail near the RF tire and use a coupler at the rear to connect the two rear brake lines.
- Thread starter
- #17
Yes, I would like to retain the tandem safety layers. I don't like having only 4wd, gears, and the e-brake to stop. I noticed when I broke the line, about half way along the frame, I lost about 80% of brake effect pretty fast. I did not make it out there tonight to faff about with the brakes.
This is what I did.
on non-abs trucks im not sure about that, but what you say makes sense on that style master cylinder and brake line setup.
on abs trucks that is incorrect, the two lines going from front to back one is for the rera brake circuit and the other is supposed to act as a sensing line. the sensing line is supposed to divert brake fluid back up the the abs unit in the event of a line failure after the proportioning valve.
ntsqd
technerd
This vintage truck doesn't have ABS. Thank god.
This is the T in question on my '88, my '84 was exactly the same:
The line at the top comes from the front brake circuit on the MC; the line at the right obviously goes to the brake caliper; the line on the left goes to the LSPV. So does the left line out of the 'L' on the left. Line into the top of the 'L' comes from the rear brake circuit on the MC.
This is the T in question on my '88, my '84 was exactly the same:
The line at the top comes from the front brake circuit on the MC; the line at the right obviously goes to the brake caliper; the line on the left goes to the LSPV. So does the left line out of the 'L' on the left. Line into the top of the 'L' comes from the rear brake circuit on the MC.
