Brakes Locking on Towed Car

Post your general and technical information, questions or responses in this forum. Viewing messages is open to all with no registration or log-in required. Prior to posting a new message or a response to an existing message, registration or login is required. Please do not post FOR SALE or WANTED ads in this section!

Moderator: bfadmin

Post Reply
BobM

Brakes Locking on Towed Car

Post by BobM »

I have had a problem recently of brakes locking on my towed car when the brakes are applied on the motor home. The car is a 1994 Honda Accord Wagon with four wheel disc brakes. The problem developed after having the rear pads replaced and the rotors adjusted. At first I thought the problem was with the Brake Buddy, but as I reflected on the problem it appears that the rear ( and/or possibly the front) brakes are the problem. The car is scheduled for service next week to check the calipers as well as all other brake parts. The Honda technicians indicated that towing my car with the automatic transmission in Neutral and the ignition switch on Accessories does not activate the ABS system, thus the brakes can lock. I am curious if anyone else has had a problem with brakes locking on a towed car.
robert

Post by robert »

I also have the Brake Buddy and a 98 Honda with ABS. To the best of my knowledge, I have not had a problem. Maybe this is something we need to address with Brake Buddy.
User avatar
whemme
Posts: 2110
Joined: Mon Aug 15, 2005 8:05 pm

Post by whemme »

BobM,

I have towed using a Brake Buddy now for 7 years. I am not saying that you may have missed an important step that you always need to do when hooking up your Brake Buddy each time you want to use it for towing, but I will describe it to make sure you know about it.

After installation of the Brake Buddy and after plugging it into a source of +12 VDC power, the internal pump should pump the unit up to whatever brake pedal pressure you selected and then the pump should shut off. Your next important step is to press and release the "TEST" button on the Brake Buddy at least 3 times with a wait of approximately 3 seconds between each pressing of that button.

The reason for doing this step is that it dumps the stored vacuum in the toad's power brake system vacuum accumulator. Even with the toad shut off and engine not running, the stored vacuum means that the toad's power brake system is still functional. And the high brake pedal pressure normally set on a Brake Buddy when applied to the brake pedal of a toad that still has vacuum stored will cause instant lockup of all four wheels on the toad. Very hard on the tires on the toad if you do this while running down the road at say 65 MPH.

Also, if you ever stop you motorhome and go back and start the toad's engine for any reason, it will restore the vacuum back into the accumulator and after shutting off the toad's engine again, you will need to press that "TEST' button again three times to dump the stored vacuum.

In my case of towing a 2005 Chevrolet Malibu, I have the Brake Buddy brake pedal pressure set to 70 lbs which provides enough pedal pressure for a reasonable amount of braking action from the Malibu with no stored vacuum in the accumulator. However, if I were to forget to dump the stored vacuum, than probably any pedal pressure above 10 lbs would be enough to lockup all four wheels on the toad.

I am pointing this out as a possible cause of you locking up the wheels on your 1994 Honda Accord when slowing down or stopping your motorhome. Honda is correct, the ABS system on your Honda is deactivated when the car is not running, but the power brake system is still functioning if stored vacuum remains in the power brake system accumulator.
Bill Hemme - Spencer, Iowa
E-mail: whemme@earthlink.net
2002 Born Free (Ford E-450 V10) 26' RSB
2016 VW Golf GTI - toad
robert

Post by robert »

Bill, thank you for the reminder. I always hit the test button when I activate the system each morning before starting out, but I have not been pushing the test button when I stop mid-day and run the engine on the Honda. Guess I have been lucky todate, as I have had only one proglem with my bake buddy, and that was when I did not install it correctly and it tipped over towards the front. The brake petal kept activating. I was driving in a city, and was able to stop and correct the problem.

Thanks again.

Regards,

Bob
BobM

Toad Brakes Locking

Post by BobM »

Bill,
I am confused regarding the test button. I always press the test button 3 or more times before towing. However, no sooner have I pressed the test button, the pump comes on and returns pressure to the desired setting.
In my case, towing a Honda of about 3100 pounds, the sensitivity is set at 4 and the pressure at 40. Before I had the rear brakes replaced, I had the sensitivity set at 5 and the pressure at 45. I drove to Florida and back without with these settings and never had a problem.
User avatar
whemme
Posts: 2110
Joined: Mon Aug 15, 2005 8:05 pm

bRAKE BUDDY PEDAL PRESSURE

Post by whemme »

BobM,

When you press the TEST button, the brake pedal plunger will press against the brake pedal with the force you have set. The pump will come on again at that time in order to maintain that pressure. However, the pressure on the brake pedal should release as soon as you release pushing the TEST button and the pump should shut off as soon as the selected brake force pressure in the Brake Buddy storage tank has recovered.

Each car is different in that with the power brake vacuum accumulator dumped, you need to set the brake pedal force on the Brake Buddy to apply enough force so that the toad will brake (decelerate) in at least a moderate manner. The amount of force you select is a function of your particular toad and your personal desire as to the braking force wanted.

With the braking force set at 40, I really don't think that would be enough force to cause your wheels to lock up on your Honda. My knowledge of the wheel lockup problems caused by the Brake Buddy is usually because the vacuum accumulator was not dumped properly before driving away with the car in tow. Also make sure that if you ever start the engine in the toad while the Brake Buddy is installed (most people do this to recharge the toad's battery during a mid-day stop) to remember to press the TEST button three times again right after you shut off the engine.
Bill Hemme - Spencer, Iowa
E-mail: whemme@earthlink.net
2002 Born Free (Ford E-450 V10) 26' RSB
2016 VW Golf GTI - toad
BobM

Locking Brakes

Post by BobM »

Hi Folks,
Thanks for the information regarding the setup of the Brake Buddy. I believe that I followed all the instructions as detailed by Brake Buddy and you folks. I recently had Honda inspect and repair my brakes. What they found was that both rear calipers needed replacement. I will know this weekend, when I tow the Accord to the Northeast Rally if the calipers were the problem.
BobM

Locking Brakes on Towed Car

Post by BobM »

Well, as I suspected, the problem was with the rear calipers. The left rear caliper was frozen and the right rear caliper was sticking. Towed the car last weekend without incident.
Post Reply

Return to “General and Technical Information, Questions, and Responses”