How to replace Bowden brake cables on your Cobra trailer

Matt Herron

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Mar 8, 2022, 8:23:40 PM3/8/22

to RAS_Prime

You don't need to remove the wheels or drums to replace the Bowden cables. Here is how I did it on my 1999 Cobra Trailer. The whole process took less than two hours, including adjusting the brake shoes (not covered in this write-up).

There are many different flavors of Bowden cables, so your milage may vary. Also, this is not meant to be an instruction manual, just a hopefully helpful documentation of how I did mine. You are responsible for your trailer safety.

First, you need enough slack in the brake rod to be able to remove the old Bowden cables. You don't need to jack the trailer up to get under it, but block the wheels, and ideally hook the tow hitch to a vehicle for safety and stability. Release the hand brake lever, and make sure the trailer has not compressed the surge cylinder if it is coupled to a vehicle.

Loosen the long and short nuts on the brake rod (some WD-40 may help) that runs along the centerline of the underside of the trailer with a 17mm open ended wrench, and back them off about a half inch from the "U" shaped equalizing lever.

Now loosen the nuts on the end of the Bowden cables nearest the equalizing lever with a 19mm open ended wrench. there is nothing to keep the cable from twisting while you try to loosen the nut, so I used a vice grip on the back side as I knew I was replacing it.

Once the nuts are off, pull one cable rearward until the threaded portion clears the key hole slot it was in. Then pull it downward so the cable passes through the slot and it's free. Do the same for the other cable.

Now push each cable forward through the "u" shaped equalizer lever until the cable clears the slot and it can be removed.

On the inside surface of the wheel hub, the Bowden cable enters the brake mechanism. Pull the cable away from the wheel, towards the centerline of the trailer. The bell housing on the Bowden cable should slide out, exposing the inner cable. Now you should be able to remove the lower half of the clamshell that the bell housing captured. This will expose more of the cable.

The swaged fitting on the end of the cable is captured by a "U" shaped clip. To remove the cable push it inward (towards the outside of the trailer), then bend the cable towards the front of the trailer. The cable can now be removed. Repeat for the other wheel.

CONGRATULATIONS both Bowden cables are free. You can now inspect them for smooth sliding of the inner cable, broken bell housings, cracked or broken rubber boots, etc.

To install the new cables, follow the above steps in reverse order. Of course don't use vice grips on the new cables. Mine seemed to tighten fine without the cable trying to rotate. When tightening the nuts on the brake rod back up, the manual says there should be no more than 1mm of slack between the "U" shaped equalizer bar and the long nut when the brakes are off. I suggest you read the Cobra manual (on their site) for servicing the brakes. It' very informative and FULL OF WARNINGS.

This might be a good time to adjust the brake shoes by following the manual if you are not sure about their condition. This is well documented, so I will not repeat the steps here.

As a final check, unhitch the vehicle, put on the hand brake, and push the trailer backwards while actuating the hand brake. The hand brake lever should not go backwards farther than vertical. If it does, re-adjust brakes shoes and/or the nuts on the brake rod per the manual.

I will post some pictures on this thread as well.

Safe towing!

Matt (J3)