| [GMCnet] GMC REAR BRAKE TORQUE REACTION MODIFICATION [message #86296] |
Thu, 27 May 2010 11:22  |
Charles Aulgur
Messages: 78
Registered: March 2006
Karma: 0
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Member |
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To: Steve and all the other folks that made all those nice comments
about my GMC rear brake improvement modification.
I am glad to see that we may be making a little progress in helping
people understand how my rear brake modification improves the braking
capability of the GMC. This concept that four of us are now driving
is not something that fell out of the sky one day. I spent many
hours and $ over about three years before I developed the current
configuration. I lost count along the way but the current design
that is being manufactured by Kim K. is around # 33. I started with
the drum brake system using a wooden mockup of the suspension system
to determine how much rotation was required for full travel of the
suspension. I talked to numerous people at GMC rallies about my
concept but the only people that showed any interest was Jim K. and
Manny. They loaned me an actual rear bogie with one suspension arm
and wheel hub which made it much easier then using my GMC. I
developed several methods of attaching to the backing plate but none
to my satisfaction, so I decided to try using disc brakes and ordered
a set from TSM. That is when I started making some progress. Jim
got a little upset because I didn't buy the disc brakes from him but
thing started to show some success and I put the first set of TSM
disc brakes with my original torque reaction system on my mid axle.
I cut a hole in my right side rear fender well and installed my video
camera looking down at the front shock which lines marked so I could
see the suspension motion. My first braking test showed that the mid
axle no longer lifted the rear of the coach. However. I was surprised
that my rear tires still slide and was also surprised that my video
camera also recored sound which was the best indicator of when the
rear tire starts sliding. Running the video frame by frame showed
the rear tire started sliding within a fraction of a second of
applying the brakes, even though it was not being lifted off the
ground. After some thought I realized that rear is pushing down on
the suspension rotation pin which results in it taking weight off
itself as the braking torque increased. That is when I realized the
rear wheel brakes are almost worthless during hard braking as they
take weight of of the tire until the tire locks up and that is when
you get the flat spots on your rear tires as most people have
experienced. The only solution for this condition is to put my
reaction arm on the rear wheels. When it is on both rear wheels you
gain 1/2 of the braking forces that was being wasted in lifting the
coach and you gain the full braking forces on the rear wheels so you
double the amount of braking capability on the rear and you will end
up with full six wheel braking.
Chuck Aulgur
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| Re: [GMCnet] GMC REAR BRAKE TORQUE REACTION MODIFICATION [message #86337 is a reply to message #86296] |
Thu, 27 May 2010 19:21  |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
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Senior Member |
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Chuck,
The reason why I got upset at Chuck for getting the TSM units is that
they are not worth the dollars spent. They are refereed to as a Baby
Caliper Basic set that is not really designed to work with the
existing Master Cylinder.
Our Phase 2 kits are superior in many ways and use GM rotors, not Ford.
We will not see pay back on this project, but thanks to our other kits
tat are moving off the shelf, we can off set the project.
On Thu, May 27, 2010 at 9:22 AM, Charles Aulgur <cwasdc@sbcglobal.net> wrote:
> To: Steve and all the other folks that made all those nice comments
> about my GMC rear brake improvement modification.
>
> I am glad to see that we may be making a little progress in helping
> people understand how my rear brake modification improves the braking
> capability of the GMC. This concept that four of us are now driving
> is not something that fell out of the sky one day. I spent many
> hours and $ over about three years before I developed the current
> configuration. I lost count along the way but the current design
> that is being manufactured by Kim K. is around # 33. I started with
> the drum brake system using a wooden mockup of the suspension system
> to determine how much rotation was required for full travel of the
> suspension. I talked to numerous people at GMC rallies about my
> concept but the only people that showed any interest was Jim K. and
> Manny. They loaned me an actual rear bogie with one suspension arm
> and wheel hub which made it much easier then using my GMC. I
> developed several methods of attaching to the backing plate but none
> to my satisfaction, so I decided to try using disc brakes and ordered
> a set from TSM. That is when I started making some progress. Jim
> got a little upset because I didn't buy the disc brakes from him but
> thing started to show some success and I put the first set of TSM
> disc brakes with my original torque reaction system on my mid axle.
> I cut a hole in my right side rear fender well and installed my video
> camera looking down at the front shock which lines marked so I could
> see the suspension motion. My first braking test showed that the mid
> axle no longer lifted the rear of the coach. However. I was surprised
> that my rear tires still slide and was also surprised that my video
> camera also recored sound which was the best indicator of when the
> rear tire starts sliding. Running the video frame by frame showed
> the rear tire started sliding within a fraction of a second of
> applying the brakes, even though it was not being lifted off the
> ground. After some thought I realized that rear is pushing down on
> the suspension rotation pin which results in it taking weight off
> itself as the braking torque increased. That is when I realized the
> rear wheel brakes are almost worthless during hard braking as they
> take weight of of the tire until the tire locks up and that is when
> you get the flat spots on your rear tires as most people have
> experienced. The only solution for this condition is to put my
> reaction arm on the rear wheels. When it is on both rear wheels you
> gain 1/2 of the braking forces that was being wasted in lifting the
> coach and you gain the full braking forces on the rear wheels so you
> double the amount of braking capability on the rear and you will end
> up with full six wheel braking.
>
> Chuck Aulgur
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription 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] GMC REAR BRAKE TORQUE REACTION MODIFICATION [message #86496 is a reply to message #86296] |
Sat, 29 May 2010 10:06 |
Larry
Messages: 2875
Registered: January 2004
Location: Menomonie, WI
Karma: 10
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Senior Member |
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| Charles Aulgur wrote on Thu, 27 May 2010 11:22 |
To: Steve and all the other folks that made all those nice comments
about my GMC rear brake improvement modification.
That is when I realized the
rear wheel brakes are almost worthless during hard braking as they
take weight of of the tire until the tire locks up and that is when
you get the flat spots on your rear tires as most people have
experienced. The only solution for this condition is to put my
reaction arm on the rear wheels. When it is on both rear wheels you
gain 1/2 of the braking forces that was being wasted in lifting the
coach and you gain the full braking forces on the rear wheels so you
double the amount of braking capability on the rear and you will end
up with full six wheel braking.
Chuck Aulgur
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Chuck,
I LOVE what you've done with he development of the reaction arm. What an innovation!! Where were you in the 70's when they were designing the GMC...
It seems that, if what you say is true about the worthlessness of the rear wheel brakes in hard braking, that (absent installing of the reaction arms) one might as well disconnect the rear brakes. Then under hard braking, at least the rear wheels would be freewheeling and have the tendency to keep the coach from swapping ends in an emergency stop.
Also, I would love to install your reaction arms, but for those of us that have a stock system with drum brakes, the money involved in making the conversion (conversion to disc brakes first, then the reaction arm) is a hard pill to swallow... at present pricing something over $4000. And that doesn't take into account the cost of "well as long as I'm in here, I might as well...do ...enter your ownwishes" or other repairs/upgrades as needed. One could do it a piece at a time, but when you are doing the disc brake conversion, you still have the rear brake lock-up problem while you are waiting to get enough money for the reaction arm, and still driving a vehicle that doesn't stop the way it could/should. There's a point at which I have to say "Stop already!!"
I know that Jimmy and others have to make a living, but if I do this project and paint my coach, these things alone nearly equal what I paid for the coach and in the case of some coaches, may be more than what the coach is worth on the open market.
I'm not criticizing the effectiveness/need for the reaction arm...just venting the frustration of it all.
Sometimes ignorance is bliss...on the other hand, what is my and Lucy's live worth? We makes our best guess choices, and takes our chances.
Larry 
78 Royale w/500 Caddy
Menomonie, WI.
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| Re: [GMCnet] GMC REAR BRAKE TORQUE REACTION MODIFICATION [message #86498 is a reply to message #86496] |
Sat, 29 May 2010 10:43 |
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ljdavick
Messages: 3548
Registered: March 2007
Location: Fremont, CA
Karma: -3
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Senior Member |
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Larry,
This is a good place to vent! I sometimes feel as you do, comparing this cost, or that cost to the initial price I paid for the coach. Heck a full tank of gas increases the value 3%! But I have to keep in mind that I bought a huge bargain. In their day these were expensive.
It's a grand hobby that will never make money for me, but pays great dividends in its use and enjoyment. Bonus points for new friends and this net that keeps us all thinking and joking and carrying on. It's an adjustment for me, but the calculations for the Motorhome don't start with $$, as most of mine do.
I'm not going to sell the farm to fix up the Motorhome, but I might sell my brother in law!
Larry Davick
The Mystery Machine
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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] GMC REAR BRAKE TORQUE REACTION MODIFICATION [message #86506 is a reply to message #86496] |
Sat, 29 May 2010 12:03 |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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Senior Member |
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| Larry wrote on Sat, 29 May 2010 11:06 |
Chuck,
I LOVE what you've done with he development of the reaction arm. What an innovation!! Where were you in the 70's when they were designing the GMC...<snip>
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Larry,
You don't seem to have included the fact that when the GMC coach was introduced, the brakes were called "Ground Breaking". Most every other vehicle in the category still had drum all around and most had non-self exciting rear drums that wet out if a dog stopped too close by.
This improvement is not to be dismissed at all, but it is, I will admit, an expensive upgrade.
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] GMC REAR BRAKE TORQUE REACTION MODIFICATION [message #86558 is a reply to message #86551] |
Sat, 29 May 2010 21:35 |
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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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Dan,
You and Teri have been crisscrossing the USA for several years and not run
into anything or anybody, get the Mustang painted! ;-)
Regards,
Rob Mueller
Sydney, Australia
AUS '75 Avion-The Blue Streak TZE365V100428
USA '75 Avion-Double Trouble TZE365V100426
-----Original Message-----
From: Dan Gregg
Larry, most of us, I suspect, have 3 times the amount we paid for coaches in
them now. No way to get that money back. I just try to enjoy the money I
have spent. I think what I may do is start a savings account for this setup.
I really do not want disc brakes on the rear but I guess to get the arm one
must do that. The paint job on my Mustang can wait.
Dan
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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] GMC REAR BRAKE TORQUE REACTION MODIFICATION [message #86601 is a reply to message #86575] |
Sun, 30 May 2010 11:06 |
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mike miller
Messages: 3576
Registered: February 2004
Location: Hillsboro, Oregon
Karma: 0
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Senior Member |
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| WD0AFQ wrote on Sat, 29 May 2010 21:47 |
One of these days the Mustang's time is coming. It wont match the GMC though.
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That's OK. Mustangs do not make very good Toads.
Mike Miller -- Hillsboro, OR -- on the Black list
(#2)`78 23' Birchaven Rear Bath -- (#3)`77 23' Birchaven Side Bath
More Sidekicks than GMC's and a late model Malibu called 'Boo'
http://m000035.blogspot.com
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