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posi rear axle and steering brakes pros cons

1915 Views 4 Replies 4 Participants Last post by  popcorn popper
What would be the pros and cons to having steering brakes on a 800 with the factory posi rear axle? I have the steering brakes on the 816 that I know can be used to slow or stop the spinning wheel but how would it work on a posi axle? How tight is the factory posi, does it grip tight or does it free spin enough to allow easy turning?

The reason I'm asking I just got a older 800 trans with keyed clutches and factory posi and I plan on pulling it apart to use the hyd gears/shaft in the 810 manual lift trans and use the posi in either the 816 with steering brakes or in the 817. Jason
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Positraction generally causes the tractor to slide sideways when traction is lost. Usually if one wheel breaks loose, the other will too and when that occurs the whole tractor turns sideways...instantly.

That is one of those ideas that sounds good but isn't. Now if it had a torsen differential, then that would be different.

Steering brakes on a posi rear end is self defeating. The harder one brake is pressed, the more the diff corrects for it.
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The rear diff on the 800s is not a locked posi so it will work with steering brakes. The diff is more like one you'd find in an old Snapper Comet. It relies on the friction of spur gears pumping oil around to achieve better traction.
You can use a set of steering brakes with the limited slip differential. Don is correct in that it is not a locked differential.

Obvious Pro's are better control on loose or wet surfaces. Another important one in my book is that the steering brakes can provide positive braking power on each axle instead of relying on the standard brake that operates through the transmission and differential. This can eliminate the experience of a free wheeling slide with no braking control.

Some Con's are the limited slip differential results in more stress being transferred to the axle keyways and hubs that can cause faster wear and failure. This wear-n-tear is made worse if the steering brake hubs are for the older straight axles. Those hubs do not have a set screw to lock down on the key and axle.

If the steering brakes you use are for the newer tapered axles this would not be a problem. But to do that you would need to use a set of tapered axles with the limited slip differential; and I don't think those axles can be swapped. I have never tried to install tapered axles in a limited slip differential, but I have the parts check it out. Below are two differentials for straight axles. The one on the left is limited slip and the one on e the right is open. I have a newer differential with tapered axles that I can use to compare, but I need to find it first.



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The diff is more like one you'd find in an old Snapper Comet. It relies on the friction of spur gears pumping oil around to achieve better traction.
Because of the design of the limited slip differential, do you think if you used higher viscosity oil in the transmission that it would change the limited slip performance?
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