Brake "thingamajiggy" at rear axle????

[Diezel_Cowboy]

Ok....last night I was topping off the axle of my '86 with gear oil and a friend was drilling out the plugged axel breather when that was done we started admiring the "thingamajiggy" near the rear axle. It is a 4 or 5 inch long lever that is now unhooked but it looks like it use to tie into the rear axle somehow. It swings from a small box that has brake line hooked up to it.

Question is what was this thing supposed to do and will putting it in a certain position (since mine is unhooked) provide more braking power?

 

[towcat]

that's the load sensitive brake proportiong valve. Rotated in a certain position, you will have delayed rear braking performance or not. Got them disconnected in all my F450's. they are a joke for towtrucks.

 

[Diezel_Cowboy]

that's the load sensitive brake proportiong valve. Rotated in a certain position, you will have delayed rear braking performance or not. Got them disconnected in all my F450's. they are a joke for towtrucks.

I knew someone would know what it is and what it does........But what positon should I put it in for best braking performance since it is unhooked from original linkage?

 

[zigg]

Originally they came hooked up with a scissor jack type mechanism, that was supposed to collapse when the box was loaded and increase braking proportional to the load in the box. The best thing you can do is to get rid of the box, and just put a "T" in the line in it's place.

There is a "proportioning valve" already built into the system. It can be found along the frame rail under the drivers seat, and it does the same thing. Of course in the newer units this is even redundant due to ABS.

Zigg

 

[94f450sd]

yup get rid of it.it does absolutely nothing but cause sucky brakes.mine are both gone.

 

[adrianspeeder]

I've never heard of this. Can anyone get a pic? What trucks came with it?

Adrianspeeder

 

[icanfixall]

As stated above its really a pain but its supposed to work just like ford designed some of their better ideas like self adjusting rear brakes.... Remove it but hope that if you ever get in an accident and the ins adjuster investigates the WHY it happen they don't find it missing or disconnected. But again its kinda like gutting a smog muffler or removing it just to "see" if it was "plugged up"...

 

[jauguston]

The valve is there to reduce the fluid pressure to the rear axle brakes when the truck has little load. Unloaded under hard braking the rear brakes will lock up causing loss of control. The valve has two selections in it, full pressure to the brakes when the springs are deflected telling the valve the truck has a load. The other position has a pressure regulating system to reduce the pressure when the springs are not flexed. On my motorhome when I installed dual 3" exhaust the linkage for the valve was in the way so I removed all the linkage for it and rotated it to the position it would be in with a full load. My MH is a load all the time.

If the valve is not causing a known problem I would think it wise to leave it in the system if your rig is a truck that can be driven light and heavy.

Jim

 

[Diezel_Cowboy]

Thanks for all the info guys.........I will check out my friends truck to see how this thing used to be hooked up, then zip tie its position so it "thinks" there is a load on the truck.

 

[Agnem]

When I built the Moose Tail I took that gizmo off. I'd rather have my foot decide when I'm applying too much brake, then a box that can fail and there is no way to know it has. Nothing is quite as reassuring to the public, as a good loud squeeling of tires on asphalt when some 3 year old has wondered into the road. At least you have proof that you tried to stop rather than no skid marks and a promise that you tried.

 

[pafixitman]

Nothing is quite as reassuring to the public, as a good loud squeeling of tires on asphalt when some 3 year old has wondered into the road. At least you have proof that you tried to stop rather than no skid marks and a promise that you tried.

Ah, but physics will tell you that rolling friction will stop you faster than sliding friction!

 

[94f450sd]

Ah, but physics will tell you that rolling friction will stop you faster than sliding friction!

but life doesnt give you enough time to slowly and steadily apply the brakes to get the physics of rolling friction to stop before hitting a kid that just ran out in front of you chaseing a ball.

plus cops would rather see skid marks if you were to hit someone or something rather than an explaination that the ABS and load sensor wouldnt allow you to lock up the brakes to proove you tryed to stop.

 

[pafixitman]

I don't disagree w/ ya Rich. Just stating a little fact...

 

[Agnem]

Your probably right Joe, but it's that thinking that brought us the anti-lock braking system, which has caused me to almost hit somebody more than a few times, when I knew I could have stopped if I could have locked them up.

 

[icanfixall]

ABS brakes are much better than locking up the brakes. When the tire locks directional control is lost and you are actually rolling on small balls of rubber tire being scrubbed off the tire to the road. It actually reduces friction with the road. Now that said, our rear ABS sucks big time. Its really not much help unless your on snow or soft roads. It has a really funny feeling when its used. I don't care for the way it works or the feel in the truck or on my foot. I'm not in favor of using it but mine seems to be working well. I just hope to never really need what I don't think to much of. I keep my rears manually adjusted up and watch the E brake for it setting about 1/4 to 3/8 down. Then I manually adjust the rears. It takes the load off the front pads too.