What is this under the back of my 74?

[cult45]

Was changing out my rear diff oil this afternoon as a part of a major service and came across this odd arrangement. It's two 'units' [?] joined by a semi-rigid wire rope. The larger of the two [first pic] sits inside the right-hand rear frame between the bump-stop and the cross-member [the pic is taken from under the rear of the truck facing forward]. From what I can see it's plumbed into the brake lines. The second 'unit' sits above the LHS axle tube [so, to the left of the pumpkin].

For a second there I thought I had a cable-locker, but then I re-grew my brain and remembered I wasn't that lucky.

Chiz brews.

 

[My4x4FJ40]

It is a rear brake propositioning valve.

 

[stayalert]

AKA LSPV (Load sensing Proportional valve)

 

[roscoFJ73]

It is a rear brake propositioning valve.

Close Its the load sensing proportioning valve (LSPV)

As you load up the rear and the suspension begins to sag,the valve applies allows more pressure to the rear brakes when you put your foot on the brake pedal.

Its found on many vehicles,I know Toyota Hiace have them.

It something to remember when you do suspension lifts as it alters the amount of load it will sense.

There are also aftermarket types that are manually adjustable,probably not legal in oz though

 

[cult45]

Cool, thanks fellas. So does it matter a hell of a lot if I went 2" over stock height? Ain't dangerous is it?

Also, is it just me or does my truck seem a little quicker now I've changed all the fluids and filters? Fuel primarily.

 

[stayalert]

Cool, thanks fellas. So does it matter a hell of a lot if I went 2" over stock height? Ain't dangerous is it?

Also, is it just me or does my truck seem a little quicker now I've changed all the fluids and filters? Fuel primarily.

cooler air temp too?

 

[Hulsty]

Cool, thanks fellas. So does it matter a hell of a lot if I went 2" over stock height? Ain't dangerous is it?

Also, is it just me or does my truck seem a little quicker now I've changed all the fluids and filters? Fuel primarily.

IMO you should adjust the rod to compensate for the lift, I increased mine to around 100mm and overall braking is MUCH improved, can lock the rears now with 35'' tyres.

 

[cult45]

Hulsty is this a brake shop adjustment or can my mechanic do it?

 

[Hulsty]

If your handy you can do it, the rod that attaches at the diff end is the once increased in length to suit my lift.

 

[cult45]

Cool, I'm up for it. Did you increase yours by 100mm and did you do a 2" lift? I'll get under there sometime in the next couple of weeks.

 

[Hulsty]

Nah I made mine about 100mm, I replaced the threaded section with a longer one so I could adjust it, mine is currently broken so the spring rod from the valve to the diff is cable tied to the car under body giving maximum rear brakes.

 

[cult45]

I think it's best if I get back under the car, sight what you're talking about and then try understand. At the moment they're known as 'diff-end thing'; 'cable thing' and 'chassis-end thing'

 

[Malahki]

Here is what I did after adding the OME 2.5" lift and extended shackles:
(keep in mind I have a real heavy front bumper and winch with no rear bumper, spare tire or back seat, so its real light on the back right now)

 

[cult45]

Here is what I did after adding the OME 2.5" lift and extended shackles:
(keep in mind I have a real heavy front bumper and winch with no rear bumper, spare tire or back seat, so its real light on the back right now)

Thanks BJ 71. Now that I see your pics it sounds like you would in theory, extend it by the amount of the lift? Give or take a few mm due to how much weight you actually carry.

 

[lj73]

you would in theory, extend it by the amount of the lift?

That's what I did. This was the simplest way that came to my mind.

Hans