Not sure if this is the right forum, but here goes:
Background - '86 Ranger 5.0, AOD, 8.8 posi rear. New brakes front and rear. No tire stagger - same front and rear
Situation -Encountered a deer on the way home tonight doing about 50 mph. Braked hard to avoid it and the rears locked up WAY before the fronts and almost put us into the ditch. Pickups tend to do that, but this was extreme and I think the extra weight of the V8 contributed to it.
I'm thinking an ABS conversion is way over my head and am wondering if a master cylinder with adjustable F/R proportioning valve is on the market. Any experience? Thanks!

 

Yes, rear brakes in pretty much any vehicle will lock up before the front, pickups are worse

Car and SUVs use 60/40 proportioning valves, pickups use 70/30

Ranger rear ABS only monitored the differential so you can still lock up one wheel

Yes, you can put on adjustable proportioning valve, you will need adapter fittings to match brake lines but not a big expense

Best to remove current proportioning valve to take it to auto parts to get adjustable valve and the fittings

There are also single line proportioning valves you can add to the rear brake line only

 

If I was to attempt to add a proportioning valve to the system, I'd do a BUNCH of testing first to determine my average stopping distance. All on the same road, and try to shoot for the same conditions/temperature, etc.. Then test it after fitting and adjusting the valve.

It would be very easy to adjust the system to get the rear tires to nearly stop locking up, but at the same time adding a good bit to your overall stopping distance.



GB :)

 

Installed a Wilwood adjustable proportioning valve. Easy install and dialed it in after a half dozen panic stops (country road with no trees!).
Now here's the thing: it stops very hard but will not lock the front brakes. Yes, there is no air in the lines. Combination of wimpy original disks and P235/55R17 tires I think. It seems there is more braking force to be had with bigger disks and/or better pads. Searching forum threads now on that topic, but if anyone has a ready reference, that would be appreciated. Thanks!

 

The F350 Master will fit on a newer Ranger, but not sure on the 1986, article here: https://therangerstation.com/tech_li..._upgrade.shtml
Important thing is the front and rear brake lines are REVERSED on the F350 master

General brake upgrade info here: https://therangerstation.com/tech_li...Upgrades.shtml

 

Great, thanks for the refs!