[Rabbit212]

1999 Pathfinder 4x4 manual got this here spring no idea what it is or does. Anyone?? Thanks

 

[PowerslavePA]

It' could be a load sensing proportion valve. When you load the rear of the
vehicle, the spring will be pulled to open the valves for the rear brake lines,
so more pressure is applied to the rear brakes with the heavy load.

If not, it's a ride height sensor for the same reason, or to adjust the rear
shock damping based on ride height. That will be measured as the axle and
chassis articulate over the road surface, and with cargo weight.

Either option, or for whatever reason, it is measuring the up and down
movement of the rear axle.

 

[Rabbit212]

It' could be a load sensing proportion valve. When you load the rear of the
vehicle, the spring will be pulled to open the valves for the rear brake lines,
so more pressure is applied to the rear brakes with the heavy load.

If not, it's a ride height sensor for the same reason, or to adjust the rear
shock damping based on ride height. That will be measured as the axle and
chassis articulate over the road surface, and with cargo weight.

Either option, or for whatever reason, it is measuring the up and down
movement of the rear axle.

Thanks. With your leads I looked around the net and yup its a load sensing valve that will adjust rear braking according to load weight or towing weight. Seems to be an expensive little part to replace if it starts leaking from what I was able to find.

 

[VStar650CL]

Seems to be an expensive little part to replace if it starts leaking from what I was able to find.

Yep, about $400 even on eBay. Just don't ever lose that spring, the rate is calibrated and they don't sell it separately.

 

[Rabbit212]

Yep, about $400 even on eBay. Just don't ever lose that spring, the rate is calibrated and they don't sell it separately.

Good to know thanks. What's your opinion on just removing the spring?? I will never have anything heavier than maybe two adults at the most in the back and zero plans to lift it or trailer anything with it. Thinking if I remove the spring its one less thing to go wrong back there....

 

[VStar650CL]

You don't want the valve arm flapping in the breeze, but there's nothing wrong with pinning it in a "normal" position and disabling the load sensing. It's just a variable proportioning valve, so test it with some very hard stops and make sure the rears aren't locking prematurely or not locking at all. If they're misbehaving, fiddle the arm position until they behave themselves.

 

[Rabbit212]

You don't want the valve arm flapping in the breeze, but there's nothing wrong with pinning it in a "normal" position and disabling the load sensing. It's just a variable proportioning valve, so test it with some very hard stops and make sure the rears aren't locking prematurely or not locking at all. If they're misbehaving, fiddle the arm position until they behave themselves.

Ok thanks for the info. Refreshing the shocks and struts this week then I'll give it a test run and check the brakes.