Servicing a Cobra Trailer Surge Brake

[John DeRosa]

Has anyone taken apart a Cobra trailer surge brake to clean/lube/fix it? 

Is there a service manual?  Any pictures or how-to information would be helpful.

Thanks.

John H DeRosa(OHM Ω)

[Matt Herron]

see my prime post  "How to replace Bowden brake cables on your Cobra trailer"

[John DeRosa]

Matt,

Thanks for that - great images BTW - but I was referring to the surge brake mechanism inside the tongue of the glider near the coupler. 

This mechanism is what actuates the bowden brake cables and then the brakes themselves.

Thanks, John OHM

[Matt Herron]

Cobra claims that mechanism almost never breaks, and it is usually something else.  What are the symptoms?

[John DeRosa]

Matt,

No known issues.  Seems to apply the brake and release it well. 

But I am thinking that cleaning out, and replacing, the 18 year old grease inside might be useful.

[Uli N]

The damper in my Cobra trailer's tongue did fail, resulting in a very harsh application of the brakes. The replacement was a straight forward job and returned the smooth brake application one wants.

There are two Zerk-fittings on the top and one on the bottom of the surge brake mechanism. I give each of them a squirt or two before setting off on a road trip using a good quality EP-grease (Extended Pressure) grease to keep everything sliding smoothly. 

The drum brakes on the trailer are supposed to be self-adjusting as the linings wear out. I still do check this periodically by peering through the inspection holes on the brake plates. Also, make sure that the equalizer(s) are straight, indicating that the wear and adjustment is even between the wheels. There is one equalizer for a single axle trailer and three for a double axle trailer. 

Trailer brake maintenance is not rocket-surgery and a must-do, if you are planning on a trouble-free road trip.

[John DeRosa]

All - Note the comment from Uli that there is a grease fitting on the BOTTOM of the tongue as well as the top.  I just found that out myself.

Uli - Could you give a short description of how you took apart the surge brake assembly?    Maybe its as simple as "I took out the visible bolts.".

Thanks, John

[John DeRosa]

PS to Uli - I re-read your post and I think that you may have replaced the entire surge brake mechanism.  Correct?

What I was thinking of was disassembling my surge brake mechanism, clean out the 20+ year old grease, then rebuild the unit.  Is this possible or is the mechanism one-unit-don't-touch sort of thing.

Thanks, John (OHM)

[David Anisman]

John,

I think you are referring to the damper. I had mine replaced in 2018. Got the replacement damper from W&W. Tubular in my case.

We used the following document as a guide. First time doing this so we learned on the job. Sections 2.3.17 and 2.3.18 mainly as I recall.

https://drive.google.com/file/d/1vpWebeeLVHEfPv0fQyZ6o_0kH2TYe4Uc/view?usp=sharing

Lots of grease, very messy job. There was some sweat and cussing to get things out and back in. Turned out fine in the end but would definitely avoid unless there is a good reason to do it.

David

C6

[Uli N]

John - I just replaced the damper element, which I got from W&W. It is basically a heavy-duty shock absorber. The shop manual cited below shows the procedure but in my case, it went without cussing or blood-letting. That is possibly due to the fact that my trailer is a fairly recent one with a square tow bar, that is attached to a V-shaped structure under the body. The trailer has a 3,500# GVW, so it is on the heavy end of the scale.

If your tow bar is made by ALKO, you should be able to replace that damper as well.

Uli