Similar to a surge-type trailer brake actuator, the AutoStop uses the momentum of your towed car as your RV slows to trigger the car's brakes to activate. Replaces the hitch bar on your Blue Ox Aventa LX tow bar for quick, easy connecting. Lowest Prices for the best tow bar braking systems from Blue Ox. Blue Ox AutoStop Supplemental Braking System - Aventa LX - Proportional - 7,500 lbs part number BX88100 can be ordered online at or call 800-298-8924 for expert service.
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Blue Ox AutoStop Supplemental Braking System - Aventa LX - Proportional - 7,500 lbs

Blue Ox Tow Bar Braking Systems

(1 reviews)

Code:   BX88100



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Blue Ox Tow Bar Braking Systems - BX88100

Similar to a surge-type trailer brake actuator, the AutoStop uses the momentum of your towed car as your RV slows to trigger the car's brakes to activate. Replaces the hitch bar on your Blue Ox Aventa LX tow bar for quick, easy connecting.


  • Supplemental braking system applies towed vehicle's brakes in proportion to braking action of RV
    • Responds to deceleration of RV to activate towed car's brake pedal with matching intensity
  • Momentum-activated device functions like a surge-type trailer brake actuator
    • Forward push of towed car causes AutoStop to contract so it pulls on the actuator cable that is attached to towed car's brake pedal
  • Adjustable tension lets you change sensitivity of unit to suit your preferences
    • Low sensitivity requires intense stopping action from RV to activate brakes in towed car
    • High sensitivity allows AutoStop to respond to even minimal slowing of RV
  • In-cab RV monitor alerts you to when towed car's brake pedal is depressed
  • Easy installation
    • Slide AutoStop into RV's trailer hitch receiver
    • Insert tow bar (sold separately) into receiver opening on AutoStop
    • Attach cable to towed car's brake pedal
  • Simple setup and removal every time you tow
    • AutoStop can remain pinned to your tow bar so you only have to set up 1 unit
    • Quick-disconnect cables let you quickly attach and separate brake pedal cable from actuating cable
  • Universal design - fits most motor-home-mounted tow bars and can easily be transferred to another towed car
  • Sturdy steel construction
  • Chrome plating provides corrosion resistance and sleek style
  • BrakeLock III breakaway kit (BRK3050) sold separately
  • Hitch locks or hitch pins and clips (to secure AutoStop to hitch and to secure tow bar to AutoStop) sold separately


  • Application: 2" x 2" trailer hitches
    • Designed for use with Blue Ox Aventa LX (BX7445)
  • Weight capacity: 7,500 lbs
  • 1-Year limited warranty

Towing your car has never been easier than with the AutoStop from Blue Ox. Setting up this supplemental braking system is a snap. Because the AutoStop connects to your Aventa LX RV-mounted tow bar (sold separately), you can slide the entire unit into your RV's trailer hitch in one fell swoop. Connect the actuating cable to the brake pedal cable - which is attached to your tow car's brake pedal - and you're good to go.

Removing the system is just as easy. The cables have a quick-disconnect feature so you only have to unplug them. Just wrap up the excess brake pedal cable and store it in your towed car. Then remove the tow bar and brake system setup from your RV's hitch. It's that simple. The AutoStop stores conveniently along with your tow bar. No need to dig out a space to stow a bulky braking unit.

Proportional Braking

A vast improvement over on/off systems, which brake at a single preset level, the AutoStop has a proportional design for equal braking. This system will activate the brakes in your towed car with an intensity that matches the braking action of your RV. The result is uniform braking across your setup. No push-pull action - just smooth, proportional braking every time.

Surge-Type Activation

When you apply the brakes in your RV, deceleration occurs and momentum pushes your towed car toward the rear of your RV. When this happens, the AutoStop contracts, applying force to its inner components. Once the internal power spring is compressed, a series of internal pulleys are set in motion. The actuating cable, which is wrapped around these pulleys, will then be tugged. This action causes the brake pedal cable - the cable that is wrapped around your towed car's brake pedal and attached to the actuating cable - to pull on the brake pedal of your towed vehicle. As a result, the brakes in your towed car will activate.

Because the intensity with which the cable tugs on your towed car's brake pedal is directly related to the intensity at which your towed car forces the AutoStop to compress, your towed car will brake proportionately to the braking action of your RV. In other words, if you slam on the brakes in your RV, your towed car's brakes will activate quickly and with maximum intensity. If you brake lightly in the RV, your towed car's brakes will activate more gradually and with less intensity.

You can also adjust the preload setting of the AutoStop, which affects the responsiveness of the system. Using the adjustment nut on the side of the unit, you can initially set the preload compression of the power spring based on the weight of your towed vehicle. Then take your rig out for a spin and test it out. You can increase the preload to lessen the sensitivity of the unit. If the preload is set to the maximum level, the AutoStop will only activate your towed car's brakes during heavy braking situations. If you set it too low, you may experience braking when you merely tap the RV brakes or when you drive down a hill.

Easy Installation and Removal

The AutoStop installs quickly and easily with no need for any modifications to your RV or towed car and no need to tap into either your RV's or towed car's brakes. The hardest part will be installing the brake pedal cable. To do this, you will have run the cable through your engine compartment and drill a small access hole through the firewall to route the cable into your car's interior.

To set up the AutoStop, just slide it into the 2" trailer hitch receiver on your RV and then insert your motor-home-mounted tow bar (sold separately) into the receiver tube that is built into the AutoStop. Connect the cable that is looped around your towed car's brake pedal to the actuating cable that comes off of the AutoStop. That's it.

To disconnect, just unhook the cables and remove the entire unit from your hitch. The AutoStop can easily be stored with your tow bar for next time - no need to find extra storage space for a bulky braking unit. The cable that is wrapped around your car's brake pedal can remain in place until you're ready to tow again. It will not interfere with normal brake pedal functioning.

In-Cab Braking Indicator

Included with the AutoStop is an in-dash indicator light that installs in your RV and will inform you when the brakes in your towed car have been engaged. Most supplemental braking systems have some sort of indicator, but many of these activate when the braking unit activates, not necessarily when the towed car's brakes are applied. If you have an indicator like this one, which informs you when the brake pedal is actually being applied, you can prevent false braking.

To install this indicator, splice the included automotive relay into your towed car's wiring between the brake light switch and the brake lights. This is to ensure that the signal sent to the indicator is actually from the vehicle and not from the braking system. By splicing into the wire at this point, you ensure that a signal will only be sent when the brake pedal is being depressed. Once the relay is in place, connect it to the included yellow wire and then route that wire out to the front of the towed car. This wire connects with the wire on the indicator that installs in the dash of your RV.

BX88100 Blue Ox Auto Stop Tow Bar Braking System - Aventa LX

BX88100 Installation InstructionsInstallation Details BX88100 Installation instructions

Video of Blue Ox AutoStop Supplemental Braking System - Aventa LX - Proportional - 7,500 lbs

Videos are provided As a guide only. Refer To manufacturer
installation instructions And specs For complete information.

Video Transcript for Blue Ox AutoStop Supplemental Braking System Installation - 2010 Chevrolet Cobalt

Today on our 2010 Chevrolet Cobalt, we are installing our Blue Ox AutoStop Supplemental Braking System, part number BX88100. Okay, now we've got everything hooked up. We've got our brake cable here. Now, when you've got it hooked up, you want about 4 inches of play. You don't really want excessive play, any more than that, then you'll start to have problems with braking and all that. Once you have that set up, come over here.

We've got our adjustment here. We go to our instructions. This is AutoStop adjustment. It has a little table for what we need to do, and based on our vehicle weight, we'll have our springs set. Then the front of the spring, if you can see in there, is going to be a little bit to the left of our halfway mark. All right, we look at our sticker here on the door.

It tells us everything we need to know about our vehicle. The number that we need to look at is the GVWR number. Our number for this vehicle, this specific vehicle, is 3795, so we take that number. We use the instructions, that little chart under the adjustments page, and we use that to figure out where that spring needs to be set for our pre-load. Our first step with our braking system here is we need to find where we're going to put it on our brake pedal brace right here.

Get a straight line, so I'm using just a long screwdriver. We'll end up mounting it to this bracket right about here, and just get a mark on your firewall to know where you're going to drill your hole. Once you have it marked, you're going to drill it with an 1/8 inch drill bit. Once you have that hole drilled, you're going to check on both sides, make sure that there's nothing in the way. Now that we have our mark back there, it's below where our steering column goes through, so I'm going to check on the back side of the firewall, roughly where I think the mark is and make sure there's nothing in the way, and then drill our 1/8 inch hole. I'm using the screwdriver so I can see where the hole sticks out on the back side.

I'm going to check to make sure we're actually not really near anything with our pilot hole before I go ahead and drill it to a bigger-sized hole. Now that I've checked on the back side and we're not anywhere near anything that we can hit, I've swapped out to my 5/16 drill bit, pull my screwdriver out, and I'm ready to drill our bigger hole. What we'll need for this step is a couple zip ties and our cable in the plastic sheath. I'm going to start by feeding our cable through, and we're going to feed it all the way through to this plastic screw knob here. You may need to go on the other side because our plastic sheath is hitting something, just to kind of route it so it won't get stuck. All right, before I feed it all the way through, I'm going to take our cable loop and loop it around our brake pedal. I'm going to go ahead and tighten our cable here and then use our plastic zip ties to tie it in place. Now, when doing it, I want to make sure it's going to be in line so our cable is straight with that plastic screw. Another thing to keep in mind when you're doing this, not that it's going to become a problem, but just want to make sure that your foot's not going to get caught on anything, so like with this zip tie, we're going to go ahead and cut off the tail, and we shouldn't have any interference when braking from the inside of our car. All right, so we've got our cable pulled through, and here's the housing that we need to route now. What I'm going to do, I'm going to route it along our subframe right here, and then it'll angle in towards the middle of our front. We can deal with that in a minute. With the provided clamps, I'm going to stick our clamp around our housing. Then use pliers of some sort to close up our clamps some. I'm going to be using self-tapping screws, but they're not provided in the kit, so if you're going to do this the same way I'm doing it, you might want to pick some up. What I'm doing right now, I'm using the end of my plier just to line up the holes a little bit better. Then go ahead and tap it in. You want to make sure that it's not too tight, that your cable won't pull through, so when I'm going to do is take the end here, just kind of push on it, and it freely feeds out, so we're good. Again, before I'm done here, I just want to make sure that there's plenty of space between our CV joint here and our plastic cable, that it's not going to be hitting our moving part here and it's not going to be coming into contact with our transmission case. All right, now we got to figure out how we're going to route this. We need to end up roughly in the middle, as close to the middle as we can, so that'll come out underneath the license plate, so I'm going to go ahead and feed this through. All right. It kind of routes itself in the straightest line possible. I'm going to do the same way as I did before, put our little clamp in place. Again, I just want to check that the end of our cable, pushing it in and pulling it back, it's not getting bound up anywhere, so we're good. All right, so I've got my clamp in place. Now I'm going to come up here. I'm going to use a zip tie. I'm going to zip tie it around my base plate that we have installed already. Just kind of keep it over to the passenger's side a little bit more so it comes out a little bit more straight on the front. All right, coming around to the front, we had this bracket that came with the kit. I drilled one of the two holes out to a 5/16 hole like the one that we drilled in the inside. Then I drilled a hole big enough to run a zip tie through our bumper, just like that. What I'm going to do, so I'll feed this under our cable. I'll run my zip tie through here. All right, and then I'll feed it through the hole I drilled already. All right, I'll reach the inside and push our zip tie back out. Pull out the slack as I get this lined up with our hole. Then I can just tighten my zip tie up. That'll keep our cable right in the middle of our car here. Then I'll just clip off the ends. All right, so now that we have this in place, we're going to need to take care of this excess sheath that we have here, so what I'm going to do is on the inside of our vehicle, that loop that we hooked around our brake pedal, I'm going to pull the cable out. I could either pull it all the way out or just make sure that all the slack is out. All right, so now we need to cut off the excess sheathing. The instructions say you can use an angle cutter, which you can. The only problem is you may encounter a little bit of clampings making it hard for you to push the cable back through because it could close off a little bit of that opening. Instead, I'm going to use a cut-off wheel on our rotary tool. Using this rotary tool, I ensure that I keep the opening as open as I can, and I didn't go right up against our bracket, just so it doesn't pop in because there's nothing holding it to the outside of that. Our next step is we're going to put our loop end on the end of this cable, so when we hook it up to our towing vehicle that we can make that adjustment. We will need 2 of these clamps. We'll need our thimble clevis here and just a pin that we'll end up using later, just to make sure that we can still fit the pin through at the end. I'll set the pin aside for now. First, I'll feed both clamps in place. Then I'll put my thimble or clevis here. I'll feed the other end of the cable back through our clamps. Now, we'll need this first clamp as close as possible to this, and then we'll tighten these in place. I'm using a 3/8 wrench to tighten these down. Now, we're not going to get too carried away because we still need to leave room for adjustments later, but I'm just going to get it snug. All right, now with that one snug, because I'm going to make the adjustments later, I'm going to clamp it further back, but when we're done, we'll have a 4 to 5-inch gap here and clamp this one down, but I'll wait till we adjust it later for that. Now, we're going to start the electrical side of our installation. This particular car does not have a stop light switch we can hook to for our electrical part of this, so we're going to RoadMaster, and we're using their stop light switch. The part number for that, for this particular vehicle, is RM-751200. Our first step is I found the grommet to the left of our pedal in there, and I've pushed an air tube through as a pull wire. When I pushed my air tube through, it was sitting underneath our fuse box. I just grabbed a piece of wire and put a hook on it and just fished it out. All right, so now that we have that through, we have our fuse wire that comes with our RoadMaster kit. What we're going to do with that is I'll strip off the end here. I'm going to strip off about 1/4 inch; that way, I can put my ring terminal on and crimp that in place. This eventually will hook up to our power, but for now, I'm just going to tuck it so it doesn't get pulled through. Now, I'm going to take our other end here, attach it to our feed wire. All right, so now that I've got everything taped up on the other side, I'm just going to pull everything through. I can take my pull wire off. We've got 1 13-millimeter bolt to take out. If you go from your brake pedal straight up, it's the only bolt in that bracket. Now, I'll grab the bracket part of our RoadMaster kit and our brake switch. All right, so I've got this L-shaped bracket that's part of the kid. I'll the 13-millimeter bolt that I just took out, and I'll feed it into place. I do want to make sure the straight edge of the L-shaped bracket is close to the brake pedal and not the other way around. Now, I take my brake switch, take the silver nut off. This is adjustable. If it's not clicking when you put it in place, then you need to adjust the bronze nut further towards the actual switch. Once you've found where that's at, that and that is in place, I can put my silver nut behind it and thread it in. All right. To check that I have it installed properly, when I push in the brake pedal, I should release a switch. If you're not hearing it release, you need to loosen it up and adjust it so the switch comes back a little bit. Basically, what we're looking for here is when the brake pedal is in its normal position, the switch is pushed in, and when the brake pedal is pushed forward, the switch is released, allowing the current through. All right, so we've got the 2 ends of wire coming off our brake switch here. We just need to clip off about 1/4 inch. Make sure 1/4 inch of the wire's showing so you can use those to connect to our other wires. Take one of the butt connectors that comes in the kit. I'm going to crimp that in place. Just going to give it a nice tug, make sure the connection's good. Now I'm going to find a way to route this wire so it's up and out of the way, and we're going to connect our red wire to that connector. Now, it doesn't matter which wire because they're both the same. They'll do the same purpose no matter what you connect to. All right. I can pull this tight and so it's out of the way, and I'll zip tie this back here out of the way to this bracket here. Now, you may or may not have this harness back here. It looks like it's an after-market, but if it's there, then great, you have something else to zip tie it to. Using the same method I did before, I tied one end of my wire to the steering wheel, and I'm going to pull the rest of it through. Now, this is going to run from the brake stop switch that we just installed down to our plug in the front that's going to plug into the RV. Now that I've got that pulled through, now I want to go straight down with it. All right, so this is the wire we just ran down, and this is the wire that we ran earlier. It runs along our shaft here that has our cable in it, up to our trailer wiring harness. That way, when we get a signal, it'll run through this wire to our RV. Now, I'm going to strip the ends off of both wires, use my butt connector, make sure I've got a good connection there, and then I'll throw some electrical tape around it just to seal out water and dirt and debris, and keep our connection from corroding. Now I'm just going to let this hang and pull the rest through the firewall. This is the connection we just made underneath the vehicle. I've pulled it all the way through so we've got no more slack left. Now I'm going to strip the end of this, throw a butt connector on it, and the other wire from our stop switch that we just put in is where I'll connect to. All right. Now I just got to tape it up and zip tie it out of the way. All right, so I've pulled this hose up out of the way. I'll grab the 2 sides here, and lift up. Now, I'm going to hook up to this post. It's going to be my power post. I've got my ring terminal here from the RoadMaster kit. Put that in place. Reinsert my bolt. All right. With the fuse already in there, I just need to zip tie this together, take up some of the slack, tuck that down here, and reinsert our cover. Now we've already routed our yellow wire from the back of the RV all the way up to the front. I've just kind of followed along with some other wire harness and zip tied along the way. I opened the front and pushed through a grommet, and I pushed a white wire through as well, which is still sitting up front, and we can show you that in a minute. That'll be our ground wire. This is going to be our power wire to turn on our indicator. I found a nice spot over here, just kind of tuck the wires up along the side. We'll cut these a little bit shorter. Then that's what's going to connect to our white. I'm going to take my strippers and strip off the ends. All right, I'll grab my butt connectors, just crimp those in place. All right, those are nice and secure. Now I'll pull my white over here, make sure these are all straight. Now, it doesn't matter which wire goes to which because the current will go through it either way. All right, I'm just wrapping my connections here. Help keep all the elements out. All right, now that I've got those covered, I'll pull the wires through. I'm just going to mount the light there. Now, the kit comes with a couple screws and nuts, but they're not long enough for our situation here, so I just grabbed a couple self-tappers. I'm just going to drill it into place. Our grommet that we ran through is right up here. You can see our yellow wire that we ran. All right, so we've taken our white wire and routed it along the top, and we used the self-tapper that was already there from another install and just put our ground wire to the body of the vehicle. If you're going to put a new self-tapper in yourself, just make sure there's nothing behind it that you can drill into. That's it for our installation of the Blue Ox AutoStop Supplemental Braking System, part number BX88100 on our 2010 Chevrolet Cobalt.

Customer Reviews

Blue Ox AutoStop Supplemental Braking System - Aventa LX - Proportional - 7,500 lbs - BX88100

Average Customer Rating:  5.0 out of 5 stars   (1 Customer Reviews)

Similar to a surge-type trailer brake actuator, the AutoStop uses the momentum of your towed car as your RV slows to trigger the car's brakes to activate. Replaces the hitch bar on your Blue Ox Aventa LX tow bar for quick, easy connecting.

- BX88100

by: robert h eckhoff08/29/2013

Owned/used one of these brakes for about 8 years-sold with last motorhome. So, was happy enough with the first one- so, bought another. That says it all bobe 97542


Yes. Five Stars. Why:- perfectly proportional always- no fiddling and adjustments- bulletproof reliable. No electronics- Easy install.Toad brakes are one of the few products that violate the principle that more expensive is better. I have never understood why people go past the best solution this type so they can spend more money for an inferior solution. None none of the electronic systems match the performance of this.I have used this for seven years. I have used other types too. I did the homework to research. I have a ms in ME.

comment by: Curt - 12/19/2013


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Information for this part was:

Expert Research:
Michael L
Updated by:
Lindsey S
Expert Research:
Michael H
Expert Research:
Jameson C
Video Edited:
Joshua S
Expert Research:
Adam R
Video by:
Kathleen M
Photos by:
Jim W
Expert Research:
Rachael H
Test Fit:
Matthew S

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Info for this part was:

Expert Research:
Michael L

Updated by:
Lindsey S

Expert Research:
Michael H

Expert Research:
Jameson C

Video Edited:
Joshua S

Expert Research:
Adam R

Video by:
Kathleen M

Photos by:
Jim W

Expert Research:
Rachael H

Test Fit:
Matthew S

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