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| about brakes [message #183185] |
Wed, 05 September 2012 12:09  |
hertfordnc
Messages: 1164
Registered: September 2009
Location: East NC
Karma: 0
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Senior Member |
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Apparently Revcon and GMC used some of the same brake parts- front caliper; Wagner CR-80941-R/CR-80940L
according to this thread here:
http://gmc.mybirdfeeder.net/GMCforum/index.php?rid=0&t=msg&th=1196
So, i guess i can replace them with JimK's 80mm calipers?
Does that typically provide a big improvement over stock? My brakes never worked well so i have no frame of reference.
Am i missing anything?
Dave & Ellen Silva
Hertford, NC
76 Birchaven, 1-ton and other stuff
Currently planning the Great american Road Trip Summer 2021
It's gonna take a lot of Adderall to get this thing right.
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| Re: [GMCnet] about brakes [message #183328 is a reply to message #183185] |
Thu, 06 September 2012 10:10  |
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USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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Senior Member |
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Dave,
You can bolt on these calipers:
http://www.appliedgmc.com/prod.itml/icOid/949
but you will need these lines too:
http://www.appliedgmc.com/prod.itml/icOid/1010
Personally I like Carbon Metallic Pads, Dave Lenzi recommended them, he has over 80,000 miles on a set and noted that his discs have
not experienced any wear. He noted that you must clean (sand) the disks which allows a transfer of materials from the pad to the
discs.
http://www.ebay.com/ctg/Performance-Friction-0052-20-Disc-Brake-Pad-/112856068
If your Revcon uses the same rear drums as a GMC you can also get carbon metallic shoes from JimK
http://www.appliedgmc.com/prod.itml/icOid/607
Regards,
Rob M.
-----Original Message-----
From: gmclist-bounces@temp.gmcnet.org [mailto:gmclist-bounces@temp.gmcnet.org] On Behalf Of dave silva
Apparently Revcon and GMC used some of the same brake parts- front caliper; Wagner CR-80941-R/CR-80940L
according to this thread here:
http://gmc.mybirdfeeder.net/GMCforum/index.php?rid=0&t=msg&th=1196
So, i guess i can replace them with JimK's 80mm calipers?
Does that typically provide a big improvement over stock? My brakes never worked well so i have no frame of reference.
Am i missing anything?
--
Dave & Ellen Silva
1972 Revcon Olds 455, toro drive train. All Stock
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Regards,
Rob M. (USAussie)
The Pedantic Mechanic
Sydney, Australia
'75 Avion - AUS - The Blue Streak TZE365V100428
'75 Avion - USA - Double Trouble TZE365V100426
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| Re: [GMCnet] about brakes [message #183393 is a reply to message #183391] |
Thu, 06 September 2012 16:43 |
Mr ERFisher
Messages: 7117
Registered: August 2005
Karma: 2
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Like here
http://gmcmotorhome.info/brakes.html#calc
FREE WIFI @ Mickey D
On Sep 6, 2012, at 2:22 PM, Emery Stora <emerystora@mac.com> wrote:
> The wider brake shoes would at first thought appear to offer better braking but you might not get any improvement.
>
> Think about it this way -- if you have a given amount of pressure on the brake shoe it would be X pounds per square inch. -- but if you increase the area of the brake shoe while still having the same total pressure you would have a lower pressure per square inch.
>
> Braking depends in the coefficient of friction between the brake shoe material and the brake drum and the overall pressure on the brake shoe.
>
> If I recall correctly it is not dependent upon the surface area of the brake shoe. If that is the case then a wider shoe would not give any better braking. I am stating this from memory and would have to do some "looking up" if someone says this is not correct. Perhaps someone else can confirm or deny this.
>
> One thing that it might give is a bit longer wear time.
>
> Emery Stora
>
> On Sep 6, 2012, at 9:50 AM, "A." <markbb1@netzero.com> wrote:
>
>>
>>
>> Robert Mueller wrote on Thu, 06 September 2012 10:10
>>> ...If your Revcon uses the same rear drums as a GMC you can also get carbon metallic shoes from JimK
>>>
>>> http://www.appliedgmc.com/prod.itml/icOid/607...
>> Before I call and pester Jim K, does anyone know if these are wider than OEM, and fill more of the 3" width of the drum?
>> --
>> '73 23' CanyonLands
>> UA (Upper Alabama)
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
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| Re: [GMCnet] about brakes [message #183413 is a reply to message #183393] |
Thu, 06 September 2012 18:18 |
emerystora
Messages: 4442
Registered: January 2004
Karma: 13
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Senior Member |
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Thanks, Gene. That is the confirmation that I needed.
We can always count on you to come through!
Emery Storai
On Sep 6, 2012, at 3:43 PM, mr.erfisher@gmail.com wrote:
> Like here
> http://gmcmotorhome.info/brakes.html#calc
>
> FREE WIFI @ Mickey D
>
>
>
>
>
> On Sep 6, 2012, at 2:22 PM, Emery Stora <emerystora@mac.com> wrote:
>
>> The wider brake shoes would at first thought appear to offer better braking but you might not get any improvement.
>>
>> Think about it this way -- if you have a given amount of pressure on the brake shoe it would be X pounds per square inch. -- but if you increase the area of the brake shoe while still having the same total pressure you would have a lower pressure per square inch.
>>
>> Braking depends in the coefficient of friction between the brake shoe material and the brake drum and the overall pressure on the brake shoe.
>>
>> If I recall correctly it is not dependent upon the surface area of the brake shoe. If that is the case then a wider shoe would not give any better braking. I am stating this from memory and would have to do some "looking up" if someone says this is not correct. Perhaps someone else can confirm or deny this.
>>
>> One thing that it might give is a bit longer wear time.
>>
>> Emery Stora
>>
>> On Sep 6, 2012, at 9:50 AM, "A." <markbb1@netzero.com> wrote:
>>
>>>
>>>
>>> Robert Mueller wrote on Thu, 06 September 2012 10:10
>>>> ...If your Revcon uses the same rear drums as a GMC you can also get carbon metallic shoes from JimK
>>>>
>>>> http://www.appliedgmc.com/prod.itml/icOid/607...
>>> Before I call and pester Jim K, does anyone know if these are wider than OEM, and fill more of the 3" width of the drum?
>>> --
>>> '73 23' CanyonLands
>>> UA (Upper Alabama)
>>> _______________________________________________
>>> GMCnet mailing list
>>> Unsubscribe or Change List Options:
>>> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
> _______________________________________________
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| Re: [GMCnet] about brakes [message #183415 is a reply to message #183413] |
Thu, 06 September 2012 18:21 |
Mr ERFisher
Messages: 7117
Registered: August 2005
Karma: 2
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Senior Member |
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Mumert is the man
very quiet, but very talented
gene
On Thu, Sep 6, 2012 at 4:18 PM, Emery Stora <emerystora@mac.com> wrote:
> Thanks, Gene. That is the confirmation that I needed.
>
> We can always count on you to come through!
>
> Emery Storai
>
> On Sep 6, 2012, at 3:43 PM, mr.erfisher@gmail.com wrote:
>
> > Like here
> > http://gmcmotorhome.info/brakes.html#calc
> >
> > FREE WIFI @ Mickey D
> >
> >
> >
> >
> >
> > On Sep 6, 2012, at 2:22 PM, Emery Stora <emerystora@mac.com> wrote:
> >
> >> The wider brake shoes would at first thought appear to offer better
> braking but you might not get any improvement.
> >>
> >> Think about it this way -- if you have a given amount of pressure on
> the brake shoe it would be X pounds per square inch. -- but if you increase
> the area of the brake shoe while still having the same total pressure you
> would have a lower pressure per square inch.
> >>
> >> Braking depends in the coefficient of friction between the brake shoe
> material and the brake drum and the overall pressure on the brake shoe.
> >>
> >> If I recall correctly it is not dependent upon the surface area of the
> brake shoe. If that is the case then a wider shoe would not give any better
> braking. I am stating this from memory and would have to do some "looking
> up" if someone says this is not correct. Perhaps someone else can confirm
> or deny this.
> >>
> >> One thing that it might give is a bit longer wear time.
> >>
> >> Emery Stora
> >>
> >> On Sep 6, 2012, at 9:50 AM, "A." <markbb1@netzero.com> wrote:
> >>
> >>>
> >>>
> >>> Robert Mueller wrote on Thu, 06 September 2012 10:10
> >>>> ...If your Revcon uses the same rear drums as a GMC you can also get
> carbon metallic shoes from JimK
> >>>>
> >>>> http://www.appliedgmc.com/prod.itml/icOid/607...
> >>> Before I call and pester Jim K, does anyone know if these are wider
> than OEM, and fill more of the 3" width of the drum?
> >>> --
> >>> '73 23' CanyonLands
> >>> UA (Upper Alabama)
> >>> _______________________________________________
> >>> GMCnet mailing list
> >>> Unsubscribe or Change List Options:
> >>> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
> >> _______________________________________________
> >> GMCnet mailing list
> >> Unsubscribe or Change List Options:
> >> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
> > _______________________________________________
> > GMCnet mailing list
> > Unsubscribe or Change List Options:
> > http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
> _______________________________________________
> GMCnet mailing list
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>
--
Gene Fisher -- 74-23,77PB/ore/ca
“Give a man a fish; you have fed him for today --- give him a URL and
-------
http://gmcmotorhome.info/
Alternator Protection Cable
http://gmcmotorhome.info/APC.html
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| Re: [GMCnet] about brakes [message #183422 is a reply to message #183415] |
Thu, 06 September 2012 18:49 |
 |
ljdavick
Messages: 3548
Registered: March 2007
Location: Fremont, CA
Karma: -3
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Senior Member |
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That chart and spreadsheet made my head hurt. Facts be damned. My beloved PO installed the 80mm calipers and I have no idea what master cylinder is in place. I did find an orphaned wire that said powermaster, so it's clear to me that he was into the brake system. I really don't know which master cylinder is best - but it looks to me like the P-30 is the way to go, no?
Does the vacuum booster ever comes into the equation as far as braking force is concerned ?
It seems to me that the best brakes possible (excluding the master cylinder and booster) are 1-Ton front and 4 disk reaction-arm rear. I would suspect the reaction arm drums would be a close second, however the maintenance of adjusting the drums might reduce their effectiveness over time. 1-Ton front end and disks on the mid-axle with parking brake only drum is probably 3rd place. Great brakes on the toad might trump all of these!
Is there an idiots guide to GMC brakes?
Larry Davick
Fremont, California
A Mystery Machine
'76 (ish) Palm Beach
----- Original Message -----
From: "gene Fisher" <mr.erfisher@gmail.com>
To: gmclist@temp.gmcnet.org
Cc: "Dave Mumert" <dmumert@gmail.com>
Sent: Thursday, September 6, 2012 4:21:26 PM
Subject: Re: [GMCnet] about brakes
Mumert is the man
very quiet, but very talented
gene
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Larry Davick
A Mystery Machine
1976(ish) Palm Beach
Fremont, Ca
Howell EFI + EBL + Electronic Dizzy
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| Re: [GMCnet] about brakes [message #183476 is a reply to message #183422] |
Fri, 07 September 2012 00:26 |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
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Senior Member |
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We also carry the 3" wide rear shoes made of carbon metallic.
In theory,the wider ones do not do more work as the coefficient of friction
is the same for both.
Saying that, we have seen the 3" do wonders on some and nothing on another.
On Thu, Sep 6, 2012 at 4:49 PM, Larry Davick <ljdavick@comcast.net> wrote:
> That chart and spreadsheet made my head hurt. Facts be damned. My beloved
> PO installed the 80mm calipers and I have no idea what master cylinder is
> in place. I did find an orphaned wire that said powermaster, so it's clear
> to me that he was into the brake system. I really don't know which master
> cylinder is best - but it looks to me like the P-30 is the way to go, no?
>
> Does the vacuum booster ever comes into the equation as far as braking
> force is concerned ?
>
> It seems to me that the best brakes possible (excluding the master
> cylinder and booster) are 1-Ton front and 4 disk reaction-arm rear. I would
> suspect the reaction arm drums would be a close second, however the
> maintenance of adjusting the drums might reduce their effectiveness over
> time. 1-Ton front end and disks on the mid-axle with parking brake only
> drum is probably 3rd place. Great brakes on the toad might trump all of
> these!
>
> Is there an idiots guide to GMC brakes?
>
>
> Larry Davick
> Fremont, California
> A Mystery Machine
> '76 (ish) Palm Beach
>
> ----- Original Message -----
> From: "gene Fisher" <mr.erfisher@gmail.com>
> To: gmclist@temp.gmcnet.org
> Cc: "Dave Mumert" <dmumert@gmail.com>
> Sent: Thursday, September 6, 2012 4:21:26 PM
> Subject: Re: [GMCnet] about brakes
>
> Mumert is the man
> very quiet, but very talented
>
> gene
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
--
Jim Kanomata
Applied/GMC, Fremont,CA
jimk@appliedairfilters.com
http://www.appliedgmc.com
1-800-752-7502
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Jim Kanomata
Applied/GMC
jimk@appliedairfilters.com
www.appliedgmc.com
1-800-752-7502
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| Re: [GMCnet] about brakes [message #183495 is a reply to message #183476] |
Fri, 07 September 2012 08:18 |
 |
Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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Senior Member |
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| jimk wrote on Fri, 07 September 2012 01:26 |
We also carry the 3" wide rear shoes made of carbon metallic.
In theory,the wider ones do not do more work as the coefficient of friction is the same for both.
Saying that, we have seen the 3" do wonders on some and nothing on another.
--
Jim Kanomata
Applied/GMC, Fremont,CA
|
Please People,
If you had high school physics, try to remember:
F=µN (Remember ? Friction is Fun??)
F = Friction Force
µ = (Mu) is the coefficient of friction (based on materials involved)
N = Normal force - the push square to the surface in pounds
Notice that surface area is not in the equation.....
F is what you want,
N is what you have,
that leaves µ as the only thing you can mess with and that is why Jim sells Carbon Metalic.
The times that JimK's customer found improvement with only wider shoes was more likely the result of finally having the brakes adjusted correctly.
There are some advantages to wider shoes in the same drum.
They will wear less. (less psi on the shoes)
They will require less adjustment (see above and auto adjust)
They may resist fade better. (a big thing as disks came on)
Matt
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
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| Re: [GMCnet] about brakes [message #183524 is a reply to message #183520] |
Fri, 07 September 2012 10:46 |
hertfordnc
Messages: 1164
Registered: September 2009
Location: East NC
Karma: 0
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Senior Member |
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I'm probably going to replace the calipers becausue they are 40 years old, the rears were disintigrated, rubber gone, grease turned into rusty sand. I assume the fronts are the same.
I'll get the 80mm calipers but the real improvement will come from the yellow sticky pads? Is that the consensus?
Thanks
Dave & Ellen Silva
Hertford, NC
76 Birchaven, 1-ton and other stuff
Currently planning the Great american Road Trip Summer 2021
It's gonna take a lot of Adderall to get this thing right.
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| Re: [GMCnet] about brakes [message #183532 is a reply to message #183523] |
Fri, 07 September 2012 11:33 |
emerystora
Messages: 4442
Registered: January 2004
Karma: 13
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Senior Member |
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Although I still dislike responding to an initial rather than to a name, you are correct.
http://www.cdxetextbook.com/brakes/brake/funda/hydropressforce.html
However when using a larger piston in the wheel cylinders more volume is required. If more is required the stroke of the brake pedal increases and if too much the pedal can bottom on the floorboard and less braking could result.
Emery Stora
On Sep 7, 2012, at 9:43 AM, "A." <markbb1@netzero.com> wrote:
>
>
> Robert Mueller wrote on Fri, 07 September 2012 10:20
>> A,
>>
>> Nope, IIRC to increase the force on the shoes you need smaller wheel cylinders.
>>
>> Regards,
>> Rob M.
> The line pressure (P per SI) from the master cylinder stays the same. In the larger wheel cylinder, the SI increases. P per SI times more SI means more P.
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| Re: [GMCnet] about brakes [message #183538 is a reply to message #183532] |
Fri, 07 September 2012 11:55 |
|
USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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Senior Member |
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Emery,
Sure glad I used IIRC as I obviously got it backwards!
DOUH!
I've filed this message under brakes so I can refer to it and no make myself look stupid AGAIN! ;-)
Regards,
Rob M.
-----Original Message-----
From: Emery Stora
Although I still dislike responding to an initial rather than to a name, you are correct.
http://www.cdxetextbook.com/brakes/brake/funda/hydropressforce.html
However when using a larger piston in the wheel cylinders more volume is required. If more is required the stroke of the brake pedal
increases and if too much the pedal can bottom on the floorboard and less braking could result.
Emery Stora
On Sep 7, 2012, at 9:43 AM, "A." <markbb1@netzero.com> wrote:
>
>
> Robert Mueller wrote on Fri, 07 September 2012 10:20
>> A,
>>
>> Nope, IIRC to increase the force on the shoes you need smaller wheel cylinders.
>>
>> Regards,
>> Rob M.
> The line pressure (P per SI) from the master cylinder stays the same. In the larger wheel cylinder, the SI increases. P per SI
times more SI means more P.
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Regards,
Rob M. (USAussie)
The Pedantic Mechanic
Sydney, Australia
'75 Avion - AUS - The Blue Streak TZE365V100428
'75 Avion - USA - Double Trouble TZE365V100426
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| Re: [GMCnet] about brakes [message #183542 is a reply to message #183538] |
Fri, 07 September 2012 12:02 |
emerystora
Messages: 4442
Registered: January 2004
Karma: 13
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Senior Member |
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As I once said, if you post often you will make a mistake once in a while. We've all done it
Emery Stora
On Sep 7, 2012, at 10:55 AM, Rob Mueller <robmueller@iinet.net.au> wrote:
> Emery,
>
> Sure glad I used IIRC as I obviously got it backwards!
>
> DOUH!
>
> I've filed this message under brakes so I can refer to it and no make myself look stupid AGAIN! ;-)
>
> Regards,
> Rob M.
>
> -----Original Message-----
> From: Emery Stora
>
> Although I still dislike responding to an initial rather than to a name, you are correct.
>
> http://www.cdxetextbook.com/brakes/brake/funda/hydropressforce.html
>
> However when using a larger piston in the wheel cylinders more volume is required. If more is required the stroke of the brake pedal
> increases and if too much the pedal can bottom on the floorboard and less braking could result.
>
> Emery Stora
>
> On Sep 7, 2012, at 9:43 AM, "A." <markbb1@netzero.com> wrote:
>
>>
>>
>> Robert Mueller wrote on Fri, 07 September 2012 10:20
>>> A,
>>>
>>> Nope, IIRC to increase the force on the shoes you need smaller wheel cylinders.
>>>
>>> Regards,
>>> Rob M.
>> The line pressure (P per SI) from the master cylinder stays the same. In the larger wheel cylinder, the SI increases. P per SI
> times more SI means more P.
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
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