LSPV question KZJ78 (1 Viewer)

[Lomoski]

Hello everyone,
I have finished my install of my Dobinson 65 mm rear suspension lift. I know I need to move my LSPV. I test drove it and as it's quite slick around town at the moment with ice I am able to lock up the fronts but not the rears at all unless I really stomp on the pedal. My understanding (which is basic) is that with the lift and not adjusting the LSPV I should actually have a rear bias on my brakes. I tried to move the LSPV down the requisite .25" and it feels like the rod that connects to the rear axle actually bottoms out in the LSPV and starts flexing the rod. So i moved it back to my stock setting.
I guess what i'm asking is:
a) does moving the LSPV down move the bias to the front
b) does moving the LSPV up move the bias to the rear
c) is it vice versa.

I have done my research on the site and everyone says to move the valve down .25" on the bracket on the frame but it feels like somethings not right when I do that.

Thanks.

Lomo

 

[coldtaco]

It’s the opposite. Lift makes the rear think it is even lighter in the back. You want to lift the arm that is attached at the axle the same amount as the lift is.

 

[Lomoski]

It’s the opposite. Lift makes the rear think it is even lighter in the back. You want to lift the arm that is attached at the axle the same amount as the lift is.

So does that mean I move the LPSV on the frame (not the adjustment on the axle up or down to move more braking to the rear?

 

[GTSSportCoupe]

You want the same angle between the lpsv rod and the frame as it was stock. To do this I made a 2" adapter at the axle to lift the rod up to account from my 2" lift. (as coldtaco said).

A couple years afterward I disconnected the lpsv completely from the axle end and zip tied it (actually a big hose clamp) up to the frame. I hated the lspv while off road, as on a very steep decent it would put all my braking to the front, and I could not stop the truck at critical times. Now I have a constant front/rear ratio and it's prefect. I like the control better on and off road. Yes, if I do lock up on the road, the back does lock up first now. But I still much prefer the way it is now.

Ideally, a person could install an adjustable brake proportioning valve and adjust to their desire.

 

[jblueridge]

When I was messing around with mine, I too made an extension for the axle connection that lifted the arm up higher.
About a year later I bought a new lspv and thngs work well now.
I should have tried to clean out the old lspv but I was lazy.

 

[kbushnz]

As said you need to lengthen the attachment at the diff end the amount of the lift you installed.
Then fine tune.

As others have also said, I have made a different adjustment bracket for mine which is no longer adjusted with body/diff movement. As I was getting the rear brakes to back off oh hill descents off roading... Not a nice feeling. Can post a photo if required.

 

[nickolai]

Is it possible/desirable to replace the whole contraption with a manual proportioningt vlave? like one of those nice wilwood ones?

 

[coldtaco]

Is it possible/desirable to replace the whole contraption with a manual proportioningt vlave? like one of those nice wilwood ones?

If it works why replace it? you get automatic adjustment with load.

 

[GTSSportCoupe]

Is it possible/desirable to replace the whole contraption with a manual proportioningt vlave? like one of those nice wilwood ones?

Yes, I have heard of people doing this.

 

[roscoFJ73]

Is it possible/desirable to replace the whole contraption with a manual proportioningt vlave? like one of those nice wilwood ones?

You lose the "load sensing proportioning" feature which means it adjusts the rear brakes to suit the load in the back.
Some landcruisers are sold with something else, its name escapes me. IMO, you are better off with the LSPV and get it working right.

 

[JuanJ]

You lose the "load sensing proportioning" feature which means it adjusts the rear brakes to suit the load in the back.
Some landcruisers are sold with something else, its name escapes me. IMO, you are better off with the LSPV and get it working right.

Hello,

x2.

In my opinion, ride is softer in a Land Cruiser when the vehicle is loaded. It is probable due to the LSPV.

If I remember correctly, there is a Light Duty Load setting on the LSPV, and a Heavy Duty Load one. Different suspension height likely has an effect on the preset load setting.

On the other hand, LSPV calibration involves two job-specific (read SST) pressure gauges and a constant rear axle load. Since other Toyota models have LSPVs, would it be possible to ask the local Toyota shop about a calibration?






Juan

 

[Lomoski]

So I have adjusted my LSPV down the requisite .25 as I'm not going to be buying gauges and doing the SST preferred method. My question still remains that it feels like the arm is bottoming out on the LSPV and when I'm going deeper into my suspension, it's not actually moving the lspv. Is my valve "stuck" or broken? Is this a normal sensation? How hard is the valve supposed to feel when i'm going deeper into my travel. I think it's just going to bend the rod if I bottom out or something.

cheers

Marc

 

[JuanJ]

Hello,

I found some setting data in the FSM.

The procedure.

This is a close-up of the shackle length adjustment. Notice that the interval for Light Duty trucks is 84 mm - 96 mm.

Hope this helps.





Juan

 

[Lomoski]

Hello,

I found some setting data in the FSM.

The procedure.

View attachment 1616664

View attachment 1616669

This is a close-up of the shackle length adjustment. Notice that the interval for Light Duty trucks is 84 mm - 96 mm.

View attachment 1616671

Hope this helps.





Juan

Thanks for the into, I understand the adjustment of the LSPV. I have a 3 inch lift, so i have to adjust it at the frame, not the rear shackle. If you add a 3 inch extension on the rear shackle, you can bend the rod on the panhard rod, it's been fairly well documented. My only questions is if the valve should feel like it's bottoming out and hard or if it should have more travel. Trying to diagnose if the valve is stuck.

 

[coldtaco]

Thanks for the into, I understand the adjustment of the LSPV. I have a 3 inch lift, so i have to adjust it at the frame, not the rear shackle. If you add a 3 inch extension on the rear shackle, you can bend the rod on the panhard rod, it's been fairly well documented. My only questions is if the valve should feel like it's bottoming out and hard or if it should have more travel. Trying to diagnose if the valve is stuck.

did you remove the part from the axle and then try moving it up and down? There probably isn't too much travel. If it feels solid at all then the valve probably is bad. I don't have any idea of what a valve should feel like, but if you seem to get full travel then just adjust up on the axle for the amount of added lift. If you put a 2" lift on lift the end on the axle two inches.

 

[Lomoski]

did you remove the part from the axle and then try moving it up and down? There probably isn't too much travel. If it feels solid at all then the valve probably is bad. I don't have any idea of what a valve should feel like, but if you seem to get full travel then just adjust up on the axle for the amount of added lift. If you put a 2" lift on lift the end on the axle two inches.

There isn't enough adjustment on the axle end. So I moved the bracket down .25 of an inch. Well documented as how to do it for a lift on ih8mud. If you add an extender on the axle, you'll bottom out the rod on the panhard rod and bend it. So you have to move the bracket down on the frame .25" for 2.5 inches of lift. Only question I have is about the valve. Should it feel stiff, is it rebuild able. Cheers!

 

[coldtaco]

There isn't enough adjustment on the axle end. So I moved the bracket down .25 of an inch. Well documented as how to do it for a lift on ih8mud. If you add an extender on the axle, you'll bottom out the rod on the panhard rod and bend it. So you have to move the bracket down on the frame .25" for 2.5 inches of lift. Only question I have is about the valve. Should it feel stiff, is it rebuild able. Cheers!

like I said I don't know how it should feel, but if you can get full travel, or what seems like full travel, then I would say it is good. I wish I had a picture of what you say the rod is hitting on. I have a LJ-78 in the garage and I don't understand where this rod is hitting.

 

[jblueridge]

I cannot find the post but I remember reading here that dismantling and cleaning the lspv gets good results.

 

[Lomoski]

I cannot find the post but I remember reading here that dismantling and cleaning the lspv gets good results.

Great! Thanks, I'll give it a go!
Cheers everyone!