Learning about the Blue OX BX88100 Universal AutoStop Hitch Connector

Some background:  When we bought the '87 Suzuki Samurai, one of the things that made it so attractive to me was that it came with Blue Ox Aladdin Tow Bars (7500lb capacity), the Sammy had a tow plate installed on it and it also had a Brake Assist device, the BX88100, to engage the Sammy's brakes when the towing vehicle's brakes are engaged, this to help both vehicles stop quickly and smoothly.

However, the PO had told me he never used the brake assist as the Sammy was so light (2000lbs +).  I also ended up never using the brake assist with the Sammy and it all functioned as expected, no problems there.

Of course, now that the Sammy is history, it was time to outfit Martha's 2014 Honda CR-V for flat towing aka all four wheels on the ground.

This week we finally got serious about testing the towing of the CR-V with the VRRV.  Several test sessions resulted in serious doubts about the performance of the brake assist device!  The VRRV seems more than capable of stopping safely with the CR-V in tow so not a huge problem, but the law in most states says that towed vehicles weighing more than 3000 lbs must have brake assistance of some sort.  The Honda CR-V weighs about 3500 lbs!

Several consultations with the ever patient and knowledgeable RichardM, finally drove the concept of how the brake assist is supposed to function into my thick head.  I had it all wrong you see, I thought it was supposed to work one way but it turns out to be completely different.  So, not knowing, I didn't know what to look for during testing.

Just for your edification and mine:  here's a pic of the vehicles hooked together from a previous posting: LINK

In the pic above, the silver colored piece, located on the tow bar right below the orange sand ramps, is the Brake Assist aka AutoStop.

Concept of operation so that others don't have my mistaken beliefs re how this device works!

As the towing vehicle slows , the towed vehicle pushes on the tow bars because of its inertia, the tow bars push on the Brake Assist, which then is supposed to move forward slightly.  There's a spring inside you see, which compresses forward pushing on one of two sets of pulleys, which in turn as they rotate/move, pull back on the cable that's connected to the towed vehicle's brake pedal, actuating it, and causing the towed vehicles brakes to actuate proportionally, helping to slow things down.

As soon as the pressure stops and the towing vehicle moves forward again, inertia forces the auto stop's inner pulley components backward; which then release the cable amount they'd pulled in, which relieves the pulling pressure on the brake pedal's cable on the towed vehicle.  The towed vehicle's brakes are now off till the next stop.

Some thorough reading/studying of the BX88100's owners/service manual (with many patient answers and explanations from RichardM via phone/textig); finally allowed me to understand how to take it apart, service it and put it back together correctly!

Let's just say, I discovered whomever had last assembled the brake assist aka auto stop, didn't do it correctly and the pulley mechanisms were stuck/binding!

Here's a closer look at the Brake Assist device.  Note: the cable conduit shown below on drive's side of the device had been mistakenly mounted on the passenger side!

Here's how the pulley components came out, with the device oriented as shown above:

I eventually figured out, using the manual and RichardM's patient help, that the above components weren't in the right order. The cable anchor (rectangular piece on the right side pulley above) should have been on the opposite side!  

I also found part of the cable off the pulley, probably causing binding.  Also the dividers have to be oriented correctly as the sides aren't equal and will bind if forced in during assembly.

I did some cleanup of the components and managed to assemble things correctly.  RichardM had said it was a pretty simple device and I managed to overcome my doubts to find that he was, as usual, quite correct.

Below pics show correct orientation of the cable, pulleys and dividers.

The picture above shows the brake assist's body in the upside down position.  This is a key point in terms of orientation when assembling the pulley components and running the wire cable!

I got everything assembled with no real issues, verified the pulleys rotated freely  and then set up for a test.

As the VRRV was now in storage, I used the tow hitch on Martha's car as the anchor point.  I simulated the pushing forward by a towed vehicle using a ratchet strap.  In the video: you can see the brake assist device moving forward slightly as I apply pressure via the strap.  

I hope you also noticed the brake assist springing back slightly when I released the ratchet strap.  That's how it's supposed to work!  I'm pretty confident now that when we next do testing with the VRRV towing the CR-V, I'll get more dependable results!

More on this when we get a chance to do actual testing.

Update: August 2.

Another disassembly and  checking of the AutoStop was required.  I didn't put the primary pulley wheels on correctly it seems.  I also needed to check the cable routing and the installation of components was done under RichardM's watchful eye via Facetime courtesy of my loving wife and camera woman, Martha.

Subsequent checks showed a retraction of the cable of at least 3 inches when the AutoStop was actuated under pressure.  This is the desired effect.

Some more testing, adjusting of the brake cable link between the AutoStop and the CR-V's brake cable end (we're at 24.5" for now) resulted in successful tests.  The brake lights on the CR-V now come on when the VRRV brakes.  

I did have to add a small bungie (Rok strap) to pull back the brake pedal as there was some slight slack on the cable.  Just enough slack to keep the brake lights activated on the CR-V which of course isn't desired.

I think we're good for towing now.  I also added a small LED light bar that should show up on the VRRV's rear view camera.  When I see it shine, I know that the brakes on the CR-V are activating.  I did this by tapping into the blue wire at the connection to the brake sensor on the top of the brake pedal.