| Re: [GMCnet] Emergency brake cable replacement [message #362557 is a reply to message #348843] |
Sat, 27 February 2021 13:39   |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Senior Member |
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If, as I've often contemplated, I installed a linear actuator for the
parking brake it's tension would be applied through a "strong enough"
spring to eliminate adjustment worries.
Ken H.
On Sat, Feb 27, 2021, 1:33 PM Ken Henderson wrote:
> I have a pneumatic cylinder beneath the brake pedal (outside) with a tube
> extension enclosing the rod and a chain to the brake pedal. A switch
> selected tiny air compressor supplies enough pressure to pull the pedal
> down with 150 lbf. 6-wheel (10 if towing) parking brakes!
>
> Admittedly not a "legal", independent system but at least f/r redundant.
> And MUCH more dependable than a line lock since it compensates for any
> hydraulic linkage until both f & r are empty. Its weak point is the
> battery -- I figure the 3 sec run every minute will deplete the battery in
> maybe a month.
>
> Ken H.
>
> On Sat, Feb 27, 2021, 12:29 PM Bill Van Vlack via Gmclist gmclist@list.gmcnet.org> wrote:
>
>> I believe Albert Branscombe is no longer making his kit. The Applied
>> website shows what looks like his kit as being currently unavailable. Re:
>> line
>> lock; A friend acquired a coach with that system and once set, could not
>> release it. Had to briefly bleed a wheel cylinder to release pressure. A few
>> folks are using linear actuators to set the rear drums; downside is that
>> the cable length has to be re-adjusted as brake shoes wear. I drove an ice
>> cream truck in the 60s that had the same lever operated e-brake as our
>> GMCs and it worked just fine holding on a grade in Pittsburgh so that I
>> could
>> go to the back and send milk shakes out of the side window. Shorter truck
>> and just two rear wheels.
>>
>> It's always seemed strange to me that the OEM system relies on steel
>> cables making turns under tension by sliding over a steel hook. More
>> tension,
>> more friction.
>> --
>> Bill Van Vlack
>> '76 Royale; Guemes Island, Washington; Twin bed, full (DS) side bath,
>> Brazilian Redwood counter and settee tops,455, 6KW generator; new owner a/o
>> mid
>> November 2015.
>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>
>
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Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| Re: [GMCnet] Emergency brake cable replacement [message #362558 is a reply to message #362556] |
Sat, 27 February 2021 13:33 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
|
Senior Member |
|
|
I have a pneumatic cylinder beneath the brake pedal (outside) with a tube
extension enclosing the rod and a chain to the brake pedal. A switch
selected tiny air compressor supplies enough pressure to pull the pedal
down with 150 lbf. 6-wheel (10 if towing) parking brakes!
Admittedly not a "legal", independent system but at least f/r redundant.
And MUCH more dependable than a line lock since it compensates for any
hydraulic linkage until both f & r are empty. Its weak point is the
battery -- I figure the 3 sec run every minute will deplete the battery in
maybe a month.
Ken H.
On Sat, Feb 27, 2021, 12:29 PM Bill Van Vlack via Gmclist <
gmclist@list.gmcnet.org> wrote:
> I believe Albert Branscombe is no longer making his kit. The Applied
> website shows what looks like his kit as being currently unavailable. Re:
> line
> lock; A friend acquired a coach with that system and once set, could not
> release it. Had to briefly bleed a wheel cylinder to release pressure. A few
> folks are using linear actuators to set the rear drums; downside is that
> the cable length has to be re-adjusted as brake shoes wear. I drove an ice
> cream truck in the 60s that had the same lever operated e-brake as our
> GMCs and it worked just fine holding on a grade in Pittsburgh so that I
> could
> go to the back and send milk shakes out of the side window. Shorter truck
> and just two rear wheels.
>
> It's always seemed strange to me that the OEM system relies on steel
> cables making turns under tension by sliding over a steel hook. More
> tension,
> more friction.
> --
> Bill Van Vlack
> '76 Royale; Guemes Island, Washington; Twin bed, full (DS) side bath,
> Brazilian Redwood counter and settee tops,455, 6KW generator; new owner a/o
> mid
> November 2015.
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| Re: [GMCnet] Emergency brake cable replacement [message #362560 is a reply to message #362557] |
Sat, 27 February 2021 14:48 |
Bill Van Vlack
Messages: 419
Registered: September 2015
Location: Guemes Island, Washington
Karma: 14
|
Senior Member |
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Ken,
How big (lb/in) and long would expect a spring need to be to just apply the two rear (not mids) shoes? Nice thing about the linear actuator is that it doesn't need power to stay applied. The other side of that is that it needs power or crawling under the coach with a wrench to release.
Bill Van Vlack
'76 Royale; Guemes Island, Washington; Twin bed, full (DS) side bath, Brazilian Redwood counter and settee tops,455, 6KW generator; new owner a/o mid November 2015.
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| Re: [GMCnet] Emergency brake cable replacement [message #362561 is a reply to message #362560] |
Sat, 27 February 2021 16:52 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
|
Senior Member |
|
|
Bill,
I've never gotten far enough into "consideration" to determine the force
needed on the brake cables to lock the brakes. It would be a simple enough
task with a scale and a way to pull it (even an improvised lever):
disconnect the single line going to the two (where you'd install the linear
actuator) and connect the scale. Pull the scale while someone turns the
wheel with a long lever. When they can no longer turn the wheel, double
(or maybe triple, depending on what the number is) the force and get a
spring that will extend under that force by maybe 1" (figuring 1" to be
more than the range of normal adjustment).
JWID, if I wuz doin' it. :-)
Ken H.
On Sat, Feb 27, 2021 at 3:49 PM Bill Van Vlack via Gmclist <
gmclist@list.gmcnet.org> wrote:
> Ken,
> How big (lb/in) and long would expect a spring need to be to just apply
> the two rear (not mids) shoes? Nice thing about the linear actuator is that
> it doesn't need power to stay applied. The other side of that is that it
> needs power or crawling under the coach with a wrench to release.
> --
> Bill Van Vlack
> '76 Royale; Guemes Island, Washington; Twin bed, full (DS) side bath,
> Brazilian Redwood counter and settee tops,455, 6KW generator; new owner a/o
> mid
> November 2015.
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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