View Full Version : Cobra Trailer Brakes
Having just installed new brake drums, bearings, backing plates, and brakes on my 2011 year Cobra (New because I burnt up the original ones on the way to Perry, a long post on that later) I am quite sensitive to how hot the brakes should get in normal operation.
I am sure that all the new items were installed properly and the adjustments were checked and are correct.
Taking the trailer from home to SCOH is a 60 mile trip. The first half is rural but with quite a few stop signs and traffic lights. I stopped several times to check and the brake hubs were hot (and I would expect some heat due to friction, physics, and all that) but how hot is too hot? I could put my finger on the hub but didn't want to keep it on much longer than a second. By comparison the brake rotors on the tow vehicle were considerably hotter than the trailer brake drums.
At one checking stop I jacked up each side and the wheels turned freely with no sound of brakes rubbing.
The second half of the trip was open highway and upon arrival at the field the brake drums were still warm, but considerable less than the stop and go portion of the trip.
The trailer tongue compresses when stopping and expands when moving in what I assume is the normal manner. I did test how much force it takes to depress the movable portion of the tongue, unhitched from the tow vehicle, and it seemed to me about 75 pounds. When released the tongue then moved out to its full extension but did take about 10 seconds to do that.
So, having said all this, is this normal operation or is something amiss?
Next time I tow the trailer I will take actual temp readings with a thermal scanner and report actual temps.
DVM
ASG29E BV
Charles Longley
May 19th 19, 01:29 AM
Disconnect the brakes and take it like a man! ;)
I had similar results after a long down hill drive that lasted maybe 30 minutes. I was down shifting, but ran about 40 mph. As I gassed up I checked the hubs and they were alarmingly hot. Didn’t want to keep my finger on the hub more than a second. After driving for another hour on level ground, they both were just warm. I concluded it was caused my the down hill run, where the surge brake was being applied because the tow vehicle was slowing down due to down shifting. Nothing else to the issue for the next 5 years.
Hope this helps,
JJ
Nelson Howe
May 19th 19, 02:00 PM
On Saturday, May 18, 2019 at 6:23:27 PM UTC-4, wrote:
> Having just installed new brake drums, bearings, backing plates, and brakes on my 2011 year Cobra (New because I burnt up the original ones on the way to Perry, a long post on that later) I am quite sensitive to how hot the brakes should get in normal operation.
>
> I am sure that all the new items were installed properly and the adjustments were checked and are correct.
>
> Taking the trailer from home to SCOH is a 60 mile trip. The first half is rural but with quite a few stop signs and traffic lights. I stopped several times to check and the brake hubs were hot (and I would expect some heat due to friction, physics, and all that) but how hot is too hot? I could put my finger on the hub but didn't want to keep it on much longer than a second. By comparison the brake rotors on the tow vehicle were considerably hotter than the trailer brake drums.
>
> At one checking stop I jacked up each side and the wheels turned freely with no sound of brakes rubbing.
>
> The second half of the trip was open highway and upon arrival at the field the brake drums were still warm, but considerable less than the stop and go portion of the trip.
>
> The trailer tongue compresses when stopping and expands when moving in what I assume is the normal manner. I did test how much force it takes to depress the movable portion of the tongue, unhitched from the tow vehicle, and it seemed to me about 75 pounds. When released the tongue then moved out to its full extension but did take about 10 seconds to do that.
>
> So, having said all this, is this normal operation or is something amiss?
>
> Next time I tow the trailer I will take actual temp readings with a thermal scanner and report actual temps.
>
> DVM
> ASG29E BV
I had to replace the pads and bearings last year because of overheating. Even after the replacement I found my hubs getting pretty warm on a short drive. We then removed the bowden cables, lubed them, got them moving freely and easily, and reinstalled them. That fixed the problem and the hubs now feel just a little warm to the touch after driving, not hot. I have a new set of bowden cables I plan to install in the future.
Nelson
Charlie M. (UH & 002 owner/pilot)
May 19th 19, 06:39 PM
Pads....???!!! I thought all were drum brakes!
Nelson Howe
May 19th 19, 08:24 PM
Sorry, shoes then.
Charles Longley
May 19th 19, 09:30 PM
That just sounded wrong lol sorry! I have two Kobra trailers now. One with brakes and one without. I am not sure what type of axle the one without brakes has. Is it possible to put electric brakes on a Kobra trailer? Has anyone done it?
Nick Kennedy[_3_]
May 19th 19, 10:59 PM
Charles
I think others have had good success with DEXTER AXLES
Don't forget to get a spare that fits and you'll have to install a Brake Controller.
This is the route I am going to take soon, maybe this summer, as my Cobra brakes are FUBAR
And I like the idea of Electric brakes on my trailers.
Matt Herron Jr.
May 20th 19, 03:13 AM
On Saturday, May 18, 2019 at 5:29:11 PM UTC-7, Charles Longley wrote:
> Disconnect the brakes and take it like a man! ;)
Monitor trailer and car tires for pressure and temperature for $200
https://www.amazon.com/Pressure-Monitoring-Careud-Temperature-Rechargeable/dp/B076ZNWGSG/ref=cm_cr_arp_d_product_top?ie=UTF8
Will a hot drum heat up the rim, then the tire so temperature at the valve stem is meaningful???
Charlie M. (UH & 002 owner/pilot)
May 20th 19, 12:10 PM
It wouldn't hurt to watch temps. Tire pressure will change by about 1PSI/10*F.
On Sunday, May 19, 2019 at 6:00:59 AM UTC-7, Nelson Howe wrote:
> On Saturday, May 18, 2019 at 6:23:27 PM UTC-4, wrote:
> > Having just installed new brake drums, bearings, backing plates, and brakes on my 2011 year Cobra (New because I burnt up the original ones on the way to Perry, a long post on that later) I am quite sensitive to how hot the brakes should get in normal operation.
> >
> > I am sure that all the new items were installed properly and the adjustments were checked and are correct.
> >
> > Taking the trailer from home to SCOH is a 60 mile trip. The first half is rural but with quite a few stop signs and traffic lights. I stopped several times to check and the brake hubs were hot (and I would expect some heat due to friction, physics, and all that) but how hot is too hot? I could put my finger on the hub but didn't want to keep it on much longer than a second. By comparison the brake rotors on the tow vehicle were considerably hotter than the trailer brake drums.
> >
> > At one checking stop I jacked up each side and the wheels turned freely with no sound of brakes rubbing.
> >
> > The second half of the trip was open highway and upon arrival at the field the brake drums were still warm, but considerable less than the stop and go portion of the trip.
> >
> > The trailer tongue compresses when stopping and expands when moving in what I assume is the normal manner. I did test how much force it takes to depress the movable portion of the tongue, unhitched from the tow vehicle, and it seemed to me about 75 pounds. When released the tongue then moved out to its full extension but did take about 10 seconds to do that.
> >
> > So, having said all this, is this normal operation or is something amiss?
> >
> > Next time I tow the trailer I will take actual temp readings with a thermal scanner and report actual temps.
> >
> > DVM
> > ASG29E BV
>
> I had to replace the pads and bearings last year because of overheating. Even after the replacement I found my hubs getting pretty warm on a short drive. We then removed the bowden cables, lubed them, got them moving freely and easily, and reinstalled them. That fixed the problem and the hubs now feel just a little warm to the touch after driving, not hot. I have a new set of bowden cables I plan to install in the future.
>
> Nelson
My experience is the same as Nelson's. I replaced the damper and the shoes, but only after cleaning and lubricating the bowden cables really well (but without removing them), making sure friction was reduced, actuation was smooth and the whole system adjusted - only then I experienced both confident braking without too much heat build up even after downgrades. They heat up the most in city stop and go traffic.
David
On Monday, May 20, 2019 at 7:10:38 AM UTC-4, Charlie M. (UH & 002 owner/pilot) wrote:
> It wouldn't hurt to watch temps. Tire pressure will change by about 1PSI/10*F.
Would it be conceivable to design a hub cap, which acts like centrifugal air pump to cool the hubs? Or install a scoop under the trailer to funnel air towards the hubs?
I have a TPM system installed which is also monitoring the tire temperature and I am impressed by how sensitive it is in both regimes.
Uli
'AS'
Charlie M. (UH & 002 owner/pilot)
May 20th 19, 08:40 PM
A more open wheel with some hubcaps could do some venting. There are some OEM car wheels (Corvette and others) that do exactly that.
Scoops/channels are likely to get torn off, especially a retrieve in a field that is soft, rough or tall grass.
While I have not made it a habit to check trailer wheel temps when towing, if the surge brake actuator is lubed and not bent, there should be almost no brake usage. Thus, no heat generated.
As far as I can tell, every time that the tow vehicle uses its brakes, the brakes on the trailer engage. Is this not the way it is supposed to work?
DVM
On Monday, May 20, 2019 at 4:37:20 PM UTC-4, wrote:
> As far as I can tell, every time that the tow vehicle uses its brakes, the brakes on the trailer engage. Is this not the way it is supposed to work?
>
> DVM
No - only if the towing vehicle decelerates fast enough so that the trailer does overcome the force of the damper in the tow bar will the brakes be engaged. If you feel a subtle 'bump in the rear' every time you tap the brake, check/replace the damper.
Uli
'AS'
How much force does it take to compress the trailer tongue. My estimate was about 75 pounds. Does this seem about right?
DVM
On Monday, May 20, 2019 at 5:00:45 PM UTC-4, wrote:
> How much force does it take to compress the trailer tongue. My estimate was about 75 pounds. Does this seem about right?
>
> DVM
I would guess that depends on the weight of the trailer. Mine is a two axle one with a max weight of around 3,500#. I would imagine that my damper requires more force to collapse than one in a trailer for a 1-26. I tried to compress my tow bar by hand and couldn't.
Only if I have to do a 'panic stomp' on the brake do I feel the bump in the rear. The three grease fittings get a few shots every year and that seems to be all required to keep it happy.
Uli
'AS'
JS[_5_]
May 20th 19, 11:42 PM
On Monday, May 20, 2019 at 3:19:55 PM UTC-7, AS wrote:
> On Monday, May 20, 2019 at 5:00:45 PM UTC-4, wrote:
> > How much force does it take to compress the trailer tongue. My estimate was about 75 pounds. Does this seem about right?
> >
> > DVM
>
> I would guess that depends on the weight of the trailer. Mine is a two axle one with a max weight of around 3,500#. I would imagine that my damper requires more force to collapse than one in a trailer for a 1-26. I tried to compress my tow bar by hand and couldn't.
> Only if I have to do a 'panic stomp' on the brake do I feel the bump in the rear. The three grease fittings get a few shots every year and that seems to be all required to keep it happy.
>
> Uli
> 'AS'
To order the correct tongue damper for a Cobra requires sending the information stamped on the trailer's AlKo tongue to Ralf at Spindelberger.
This would imply there are different dampers, different forces.
(several are in stock at W+W)
When the damper is REALLY gone, you'll feel and hear a loud clunk on starts and stops.
Jim
I have contacted Cobra and they told me that my trailer has 2051 brakes and the overrun device is 161S. However; that still does not tell me what the compression force is? As noted above the trailer tongue compresses with i'm guessing 75 pounds of force and then extends out to its full extension in about 10 seconds.
DVM
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