Load sensing proportioning valve (lspv)

I'm replacing brake lines on my 1992 V6 Camry and I have a LOAD SENSING PROPORTIONING VALVE (LSPV).

My manual states these are only used on stationwagons and toyota trucks. This 92' was built in 1991 in Japan apparently in a special factory. This car has its original exhaust system including a very large muffler.

I only have 194,000kms. on it.

I don't fully understand what this valve does and how it operates?:confused:

I've taken it off and fully cleaned and repainted it.

Could someone provide operating information on it?

Thanks in advance.

Murr

http://auto.howstuffworks.com/auto-parts/brakes/brake-types/master-brake2.htm
Scroll towards the bottom

A LSPV is more complex than a standard proportioning valve. The garden variety proportioning valve is used on a vehicle with front discs and rear drums. It keeps the full pressure of the braking system from being applied to the drums, preventing them from locking up. Everything else being equal, drums need much less line pressure than discs. The LSPV is linked to the rear suspension, detects the suspension height and alters the pressure allotted to the rear brakes accordingly.

When the trunk or bed is empty, the suspension is unloaded and the body sits high. The LSPV detects this lack of load and prevents the lightly loaded rear brakes from locking up by proportioning more pressure to the front brakes. When the rear of the vehicle is highly loaded, the LSPV alots a higher ratio of pressure to the rear brakes since they are pressed more tightly against the road and, under these circumstances, transmit greater braking force to the road and assist in stopping to a greater degree than when they are less loaded.

Thank you RIP and Brian.

I have gained a good understanding for its reason for being there.

A second question. Do all vehicles have this valve ?

No. It is most used on trucks.

Further to my LSPV.
With the hydraulic brake lines pressurized to this valve at the rear, I am not getting any hydraulic fluid to the wheel lines.
How can this LSPV be checked ?

Thanks.

Murra

To check it, the pressure differential between the front and rear brake lines has to be measured with gauges. The pressure differential is changed by changing the position and preload on the valve tensioner. If it cannot be adjusted, then it needs to be replaced.

Bring it to a dealer for testing. Replacing the valve requries testing and adjustment best left to the dealer or competent and well-equipped mechanic.