Toyota Hilux Vigo Champ Pre Runner 2012 Load Proportioning Valve.

[Formaleins]

Now that I seem to have a working handbrake on my truck, I want to get it tweaked. It is a lot better than before but I still feel it is using the front pads a lot more than the rear drums.

On the Toyotas there is an LSPV on the rear axle, what I would be interested in is how to adjust this to give more emphasis on the drums rather than the pads?

 

The guy that fitted new shoes and di the drums went under the truck and fiddled with it a bit but I was not sure how he biased it and he wasn't exactly "sharing"

 

Most of the time the truck runs empty and these days it will never see anything like a ton in the back.

 

What I would like to do is get the rear brakes to bite a bit earlier, even though they are now working, it still feels like the front end is doing 90% of the work. If I could get it to the point where maybe 60% is on the front and 40% on the rear (with no load in the bed) it might help.

 

Anyone know how to adjust this thing to transfer more braking to the rear? (I know it is a complex process with pressure and the like according to Toyota, but someone must have done it by trial and error) If you have, I would love to hear which nuts and bolts to turn to start the adjustment. once I am clear on that, then I am happy to do my own trial and error.

 

Cheers!

[Formaleins]

From other forums...

 

 

To give more power to the rear brakes would you lengthen or shorten the distance "A" - Stock is about 194 mm. Details from Toyota seem contradictory.

 

Cheers!

Edited September 12, 2020 by Formaleins

[stubuzz]

I think the adjustable rod should be increased,(increase preload)  but can't rally tell from the picture. Add some weight in the back and watch the action on the valve. You should aim to mimic that with your adjustment.

Warning: Be careful with random back lock ups, especially in the wet.

[Formaleins]

6 minutes ago, stubuzz said:

I think the adjustable rod should be increased,(increase preload)  but can't rally tell from the picture. Add some weight in the back and watch the action on the valve. You should aim to mimic that with your adjustment.

Warning: Be careful with random back lock ups, especially in the wet.

Me too, even the Toyota advice is confusing.

Edited September 12, 2020 by Formaleins

[stubuzz]

Increase the distance between A&B.

[Formaleins]

4 minutes ago, stubuzz said:

Increase the distance between A&B.

Thanks, I will give it a go tomorrow! I was not sure because of the second pivot point near to the valve, thanks for your help. appreciated. I have had so much garbage from so called mechanics with my brake issues the last few weeks it has been driving me mental.

Edited September 12, 2020 by Formaleins

[NanLaew]

Do Toyota handbrakes work on the front wheels as well?

 

The load proportioning valve looks like it is essential for balancing braking loads between front disk and rear drum brakes for stability under normal braking. Doesn't seem to be anything to do with hand brakes and certainly not something I would see as needing tweaking. I can imagine a sudden rear wheel lock-up on braking on a wet surface with a heavier load in the back could be a recipe for disaster. With all these high-topped pickups with heavily modified rear suspension and low profile tires lying upside down in the central median, maybe it is already?

[Formaleins]

2 minutes ago, NanLaew said:

Do Toyota handbrakes work on the front wheels as well?

 

The load proportioning valve looks like it is essential for balancing braking loads between front disk and rear drum brakes for stability under normal braking. Doesn't seem to be anything to do with hand brakes and certainly not something I would see as needing tweaking. I can imagine a sudden rear wheel lock-up on braking on a wet surface with a heavier load in the back could be a recipe for disaster. With all these high-topped pickups with heavily modified rear suspension and low profile tires lying upside down in the central median, maybe it is already?

Not on the Vigo Champ or Tiger.

[transam]

https://www.hilux4x4.co.za/brakes/

[Formaleins]

9 minutes ago, transam said:

https://www.hilux4x4.co.za/brakes/

Many thanks, some great info there! I have just adjusted mine (lengthened it) and will give it a try - It was definitely lower than stock.

[Lancashirelad]

Load sensing valves have a habit of seizing up & failing to work correctly if the vehicle is rarely loaded.

BE VERY CAREFUL playing around adjusting this yourself otherwise in the wet you may find yourself looking back where you just came from.

When you're done, I'd suggest going back to see your friendly rolling road guy again to make sure you don't have too much force going to the rear brakes. You should be able to ascertain the correct front bias for your vehicle.