# Load sensing valve 1991 d21



## Arayt (Jul 3, 2011)

Anybody ever bypassed load sensing valve? Mine is leaking and cannot find replacement. I saw were Toyota owners are bypassing theirs, hopefully I can do the same.
Thanks Ray


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## jp2code (Jun 2, 2011)

Where is the load sensing valve located?


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## smj999smj (Jan 1, 2006)

The load sensing valve is by the rear axle. It's a proportioning valve that adjust the rear brake fluid pressure based on the difference in height between the axle and the bed of the truck, which will vary depending on the weight of the load in the bed. It "could" be bypassed, but it will affect the brake performance when the bed is weighted down. If you drive around with a light load or empty most of the time, you probably won't notice the difference. I'm showing a part number of 46400-32G00 with "limited availability," which often means if it's not sitting on the shelf at someone's dealer, it's not available. It's also not cheap with online prices around $320 and an MSRP over $400, but cost is irrelevant if you can't find the part! Salvage yards might be the only option if you can find one that's not all rusted apart.


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## Arayt (Jul 3, 2011)

Thanks for the info i.e. part number. Do you know if it can be rebuilt, seems like there should be an O-ring or some type of packing around the piston that moves in and out? I have not remove it from the truck yet but its hard to believe it can't be rebuilt.
Thanks, Ray


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## smj999smj (Jan 1, 2006)

Nobody makes a rebuilding kit and I've yet to hear of anyone who has.


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## Arayt (Jul 3, 2011)

Well I got her off and broke it down as far as I can. There are two plungers inside the housing one is held in place with a solid drive pin that was not meant to be removable (i drilled it out and was able to removed one of the plungers) the second is held in place with a clip that snaps into a cone shaped core with the second plunger running through the center of it and that's not removable with destroying the housing. Though I was getting some where for a while. Guess I'll go to plan "b" and try bypassing it. Another interesting thing, it has a stamp in the housing that looks like a chevy bowtie. Still would like input on bypassing it.
Thanks, Ray


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## smj999smj (Jan 1, 2006)

All it does is help the brakes compensate for a loaded bed. For years, trucks never had a load sensing valve and they were fine and yours will be fine if you bypass it. It's a nice feature to have, but if you can't find a new or rebuilt replacement, it limits your options to either bypassing it or finding one in a junkyard.


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## Arayt (Jul 3, 2011)

Thanks smj, I did find out Mitsubishi has the same unit under some of their trucks and you can purchase them over seas. I'll be bypassing mine.
Thanks again, Ray


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## Arayt (Jul 3, 2011)

Well I got her bypassed and she breaks just fine. I did have an issue locating a plug so I ended up installing a bolt M10 x 1.0 thread pitch. So far no drips no runs no errors.
Thanks, Ray


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## belmoosto (Nov 12, 2021)

smj999smj said:


> The load sensing valve is by the rear axle. It's a proportioning valve that adjust the rear brake fluid pressure based on the difference in height between the axle and the bed of the truck, which will vary depending on the weight of the load in the bed. It "could" be bypassed, but it will affect the brake performance when the bed is weighted down. If you drive around with a light load or empty most of the time, you probably won't notice the difference. I'm showing a part number of 46400-32G00 with "limited availability," which often means if it's not sitting on the shelf at someone's dealer, it's not available. It's also not cheap with online prices around $320 and an MSRP over $400, but cost is irrelevant if you can't find the part! Salvage yards might be the only option if you can find one that's not all rusted apart.


I think I see mine eBay for $33 but they're under Mitsubishi


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## jp2code (Jun 2, 2011)

belmoosto said:


> I think I see mine eBay for $33 but they're under Mitsubishi


Mitsubishi is the manufacturer of several Japanese sensors.


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