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In most all of the literature on my Rav that I've found on the Internet, there are many references to it having a Load Sensing Proportioning Valve as part of the braking system. I found this interesting, since that is a feature usually reserved for pickup trucks and other vehicles with solid rear axles. I figured it was a typo, however it has been mentioned on so many Toyota websites with reference to the Rav4 that I thought it had to be true.

An LSPV (for those of you who don't know) is a simple lever-controlled valve that is located on or near the rear axle of (usually) a pickup truck or SUV. In a nutshell, it regulates braking pressure to the rear wheels depending on the payload in the vehicle, essentially keeping the rear brakes from locking up when there is little weight, and applying more pressure when the rear is loaded down.

A regular Brake Proportioning Valve (BPV) is standard on all cars and trucks, most often as part of the master cylinder or located nearby on the firewall. BPV's control the brake bias (front vs. rear) and most BPV's are permanently set at the factory for the standard setup of the vehicle. An LSPV goes one step further, by actually adjusting the rear brake pressure depending on the load in the back of the vehicle, through the use of some form of lever to determine the height of the suspension and adjust the pressure accordingly.

Well anyway, my question is this- does my Rav have an LSPV, if so then where the heck is it located? The reason I'm interested is because it affects the bleeding procedure for the brakes. I have found what I believe to be a standard BPV on the firewall behind the engine, however can't seem to find anything under the Rav that remotely resembles the LSPV's that I am familiar with.

I should mention that my Toyota service manual mentions the "proportioning valve" but makes no distinction whether it is a regular BPV or an LSPV. No pictures/diagrams/references; it just shows to connect pressure gauges to the caliper/cylinder bleeders to determine if the P-valve is functioning correctly.
 
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Jeff,

Here is a thought, though I could be wrong. They may have fitted a standard proportioning valve to vehicles with drum brakes on the rear, and a load sensor to vehicles fitted with discs to the rear as not to have a load sensor would make the vehicle lethal in the wet. Just a thought
 
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