Home » Public Forums » GMCnet » Rear Disk Brakes
| Rear Disk Brakes [message #64105] |
Fri, 13 November 2009 01:45  |
Ron
Messages: 250
Registered: February 2004
Location: Conifer, Colorado
Karma: 0
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Senior Member |
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Hi All..
I have been fighting with the rear brakes on my coach for as long as I have owned it.. I have never been happy with the brakes and it looks like I may be ready to take the next step.
I am considering putting disk brakes on at least one axle of the rear of my coach. From what I have been able to gather the rear wheels do not add that much to the overall braking of the coach. My brakes currently suck  so I may start with one axle and do the second if it is warranted.
I have looked at the Harrison kit (expensive but the largest capacity) Jim K's.. It is available for all 4 rears and looks like a good kit About 1/2 the cost of the Harrison kit per axle). And saw the TSM manufacturing kit that looks like it may be about the same as Jim k's but it is available with several options and can be bought per axle.
Many of you have experience with any of these? Do you need to keep or add the prop valve to the system?
Any real world experience would really be appreciated.
Ron
now a P.O.
Conifer, CO
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| Re: [GMCnet] Rear Disk Brakes [message #64125 is a reply to message #64105] |
Fri, 13 November 2009 09:14  |
Jim White[1]
Messages: 144
Registered: September 2008
Karma: 0
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Senior Member |
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Ron-
What I know about TZE brakes is that there are so many components that
effect stopping ability that no one change will guarantee much
improvement. You need to either correct all of the key components or do
enough testing to be able to correct just the weakest link. That is
very difficult to do BTW.
When I asked the experts at the Harrington Convention why my coach
wouldn't stop very well, I received a different answer from each
person. I even got two contradictory answers from one vendor two days
apart.
After cruising through a stop sign at the intersection of two US
highways with both feet on the brake, I drove straight to Leigh
Harrison's house, parked it in his front driveway and said let's fix it.
We replaced the master cylinder, the sensitized booster, upgraded the
front calipers & pads, installed new front rotors, and then I installed
his 12.5" rotors kit on the center axle.
Could I have done less and still been able to stop? Maybe, but as I
disassembled the front I found a pad worn to the metal and a failed
bearing so I did a complete front end upgrade with Lenzi's good stuff
and Leigh's better brakes on the front. The coach still wouldn't stop
that well so we replaced the master cylinder and booster. While that
was being done, I installed the 12.5" kit on the center axle, and when
we tested it, that heavy hog stopped very responsively. I also
installed a vacuum pump so that I have brakes after the engine stalls.
Already proved to be a very nice feature.
According to an article by Frank Cosmos, the 12.5" rotors have superior
stopping ability over any other disc upgrade. (I'll email you the
chart) I'm sure that Chuck's reaction arm kit would make it even better
in panic stops but I avoid those panic stops by applying the brakes
early and continuously since the hotter they get the better they seem to
stop with the metallic brake shoes and pads.
I am very happy with this set up and I see no reason to put disc on the
rear axle and then spend another $ 500 for a replacement parking brake.
HTH-
Jim "Doc" White
Wintergreen, VA
75 GMC Stretch- (that stops pretty darn good for a heavy hog)
rhusak wrote:
> Hi All..
> I have been fighting with the rear brakes on my coach for as long as I have owned it.. I have never been happy with the brakes and it looks like I may be ready to take the next step.
> I am considering putting disk brakes on at least one axle of the rear of my coach. From what I have been able to gather the rear wheels do not add that much to the overall braking of the coach. My brakes currently suck 8o so I may start with one axle and do the second if it is warranted.
> I have looked at the Harrison kit (expensive but the largest capacity) Jim K's.. It is available for all 4 rears and looks like a good kit About 1/2 the cost of the Harrison kit per axle). And saw the TSM manufacturing kit that looks like it may be about the same as Jim k's but it is available with several options and can be bought per axle.
> Many of you have experience with any of these? Do you need to keep or add the prop valve to the system?
> Any real world experience would really be appreciated.
> Ron
>
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| Re: [GMCnet] Rear Disk Brakes [message #64127 is a reply to message #64125] |
Fri, 13 November 2009 09:26 |
tphipps
Messages: 3005
Registered: August 2004
Location: Spanish Fort, AL
Karma: 9
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Senior Member |
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My coach has the TSM mid-wheel disk brakes. As a point of GMC history, this coach was the one that TSM did as the first one for Bill Harvey, GMC Western States. Their site had a write-up that he did on the process.
They work, it stops. I did change to JmK yellow front pads to help handle the heat coming down from Flagpole Knob, VA, After 3.5 miles down hill on un-improved mountain fire trails, they do heat up a little.
Tom Phipps,
75 GMC Ex-Avion
2012 Phoenix Cruiser model 2552
KA4CSG
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| Re: Rear Disk Brakes [message #64130 is a reply to message #64105] |
Fri, 13 November 2009 09:46 |
LYNN L
Messages: 140
Registered: March 2005
Location: Pearland TX.
Karma: 0
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Senior Member |
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Ron. the first thing you have to realize is that you are re- designing a complete brake system. I have changed to an all disc system with a custom hydroboost unit and a p30 master cylinder that is capable of applying close to 2000 lbs. of hydraulic pressure to each disc. My GMC stops like a van now and the white knuckle stuff with 2 legs on the pedal are long gone. There is so much good info on the conversion on this site and some excellent photos and parts required lists at b dubs place that I will only briefly describe my system. I am using 80 mm calipers on the front end, 2.9 inch calipers on the mid axle and 2.5 inch cadillac rear calipers on the rear axles. I tried many combinations and sizes on the rear and found this to work the best with the volume output of the master cylinder. Good luck and do your research well before you start. If I had been able to attend some of the rallys before I started the project and talked to more of the knoweledgable folks on this site, I"m sure it would have saved me a lot of time and money.
Lynn
Lynn L
76 Eleganza Cad.500
Pearland TX.
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| Re: [GMCnet] Rear Disk Brakes [message #64147 is a reply to message #64135] |
Fri, 13 November 2009 12:06 |
GMCWiperMan
Messages: 1248
Registered: December 2007
Karma: 1
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Senior Member |
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Unless you know how to do them yourself, Dave Mumert's brake force
calculations at:
http://gmcmotorhome.info/GMCBrakeCalcs.pdf
<http://gmcmotorhome.info/GMCBrakeCalcs.pdf>are essential reading before
doing brake modifications. Of particular interest is the "Clamping Force"
chart. That's what tells you how much sheer braking capacity you can
attain. But it can't be used blindly; for example, it shows that a 1-1/8"
Master Cylinder with 80 mm calipers will give you almost as much braking
force as a much more complex Hydroboost system with those same calipers.
But if you look back up the page at the MC piston travel required to supply
just two 80 mm calipers, you'll see that the 1-1/8" MC requires 0.784".
While it's difficult to find specifications for MC's, tests I did back in
'03 indicate that about 0.75" is the most travel we can expect. That says
the 1-1/8" MC cannot support two 80 mm calipers. Before anyone gets too
excited, remember that Dave's calculations are based on caliper travel of
0.050", an arbitrary, hopefully worst case, standard some of us agreed to
some years back for such calculations. IMHO it would be foolhardy to risk
running out of MC capacity with such a setup.
One big factor in favor of Leigh Harrison's brakes is the 12.5" rotors he
uses. Remembering that the amount of braking force "at the road" is
directly proportional to the radius of the rotor, with the same MC and
calipers, his brakes will produce 13.6% more braking force than with the
more common 11" OEM rotors. That's a BUNCH and is the one factor not
covered by Dave's calculations.
Ken H.
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| Re: [GMCnet] Rear Disk Brakes [message #64150 is a reply to message #64147] |
Fri, 13 November 2009 12:38 |
Ron
Messages: 250
Registered: February 2004
Location: Conifer, Colorado
Karma: 0
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Senior Member |
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Ken..
Damned.. You are a wealth of info!
It looks like the hydroboost is the hot number.. Anyone making them as a kit? What about the electric booster?
I was always planning to go with the larger master with the disk brakes..
Ron
now a P.O.
Conifer, CO
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| Re: [GMCnet] Rear Disk Brakes [message #64159 is a reply to message #64141] |
Fri, 13 November 2009 14:09 |
Larry
Messages: 2875
Registered: January 2004
Location: Menomonie, WI
Karma: 10
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Senior Member |
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| Ron wrote on Fri, 13 November 2009 11:34 |
Hi All..
Lots of really good info...
I should have mentioned what I have already done...
80 mm Front Calipers
Sensitized Brake booster (Twice it was changed due to poor brakes)
New Master Cyl. (3 times due to replacements leaking)
All New Brake flex hoses all wheels
New Combo Valve
Auxiliary vacuum pump (really needed here at high altitude)
All new rear wheel cyls.. In 2 different sizes as recommend)
All new shoes.
So I think I have been down the proper upgrade path but still brakes suck! I almost wrecked the coach on I25 on the way to the Pueblo rally.
I wanted to do the rear disks as I tow a vehicle with a brake buddy (My brakes are much better then) And I deal with steep mountain passes all the time..
The rear disks should dissipate heat much better from the downhill side of the passes..
A Power Master electrical system was mentioned.. Where is that available.. Any place I have looked they are NLA. This is something I have also looked at..
Again.. I am not trying to reinvent the wheel (or the brakes in my case) But none of the normal stuff has helped..
Oh and yes I have pressure bled, Gravity bled and adjusted them a hundred times.. But the brakes still suck! I have even tried a set of Jim's "Yellow" pads.. I wore them in about 6000 miles.. I think that the fronts are really overworked..
That is where I am at and really could use the advice.. 
Ron
|
Ron,
When I brought my GMC home from Houston (to Wisconsin) I found my brakes exactly as you describe, I also coasted through a stop light with both feet on the brakes. So the first thing I went for when I got it home was brake upgrade. I did exactly as you described above with a modest improvement in braking, but not what I felt was up to my personal comfort level. On the advice of several on the net, I pulled off the new MC and sensitized booster. I then bought and installed a Power Master system, leaving the rest of the brakes (80mm calipers with performance friction pads, 15/16" rear and 1 1/16" WC's new hoses and carbon metallic shoes) alone. Now....on my coach...the PM made all the difference!! It now stops like a Modern PU truck with only a light touch on the brake pedal.
Here is a list of the Autos that this was available on:
MODELS AFFECTED:
1985 REGAL 3.8L TURBO (ENGINE VIN CODE 9) AND RPO LM9 BRAKES
1986-87 REGAL 3.8L TURBO (ENGINE VIN CODE 7)
1986 LESABRE AND ELECTR ESTATE WAGON
1986 CHEVROLET CAPRICE STATION WAGON
1986 PONTIAC PARISIENNE WAGON
1986 OLDSMOBILE CUSTOM CRUISER STATION WAGON
Part # for Buick Regal Turbo is 52-9702. Part # for the others is 52-9700.
The 9702 and 9700 are functionaly the same, but for some reason the 9700 is considerably cheaper.
You can find this at Autozone. Just pick one of the Station wagons above, create it as one of your vehicles at the AZ web site and search for it under brake parts, or search using the part #.
FWIW, this is where I found it:
http://tinyurl.com/yhds7se
At $440.00 it's not cheap, but was a fairly easy install. While this solution has worked well for me, there are some that would not do this. I would encourage those that see the disadvantages to using the PM, to post their reasons. I am *not* offended by this. Those interested in doing this need to know *everything* about what they are getting themselves into.
So...JWID
Larry 
78 Royale w/500 Caddy
Menomonie, WI.
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| Re: [GMCnet] Rear Disk Brakes [message #64163 is a reply to message #64159] |
Fri, 13 November 2009 14:49 |
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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,
Was the Power Master a simple bolt-on + wiring?
I have those beautiful stainless brake lines from Tom Hampton, as well as larger front rotors, but my brakes are sometimes a two footed affair. I simply don't have the budget to go with what I want - Chuck's reaction arm set up. I saw the mock-up at Jim K's place and after scratching my head all afternoon I finally "got it!" Now I wish I had it...
I just know that I should search Gene's site, as there is probably a detailed discussion as to what to do, but I'm eating lunch at work, and I'm lazy!
Thanks,
Larry Davick
The Mystery Machine
----- Original Message -----
From: "Larry" <weidnerl@wwt.net>
To: gmclist@temp.gmcnet.org
Sent: Friday, November 13, 2009 12:09:48 PM GMT -08:00 US/Canada Pacific
Subject: Re: [GMCnet] Rear Disk Brakes
Ron wrote on Fri, 13 November 2009 11:34
> Hi All..
> Lots of really good info...
> I should have mentioned what I have already done...
> 80 mm Front Calipers
> Sensitized Brake booster (Twice it was changed due to poor brakes)
> New Master Cyl. (3 times due to replacements leaking)
> All New Brake flex hoses all wheels
> New Combo Valve
> Auxiliary vacuum pump (really needed here at high altitude)
> All new rear wheel cyls.. In 2 different sizes as recommend)
> All new shoes.
> So I think I have been down the proper upgrade path but still brakes suck! I almost wrecked the coach on I25 on the way to the Pueblo rally.
> I wanted to do the rear disks as I tow a vehicle with a brake buddy (My brakes are much better then) And I deal with steep mountain passes all the time..
> The rear disks should dissipate heat much better from the downhill side of the passes..
> A Power Master electrical system was mentioned.. Where is that available.. Any place I have looked they are NLA. This is something I have also looked at..
> Again.. I am not trying to reinvent the wheel (or the brakes in my case) But none of the normal stuff has helped..
> Oh and yes I have pressure bled, Gravity bled and adjusted them a hundred times.. But the brakes still suck! I have even tried a set of Jim's "Yellow" pads.. I wore them in about 6000 miles.. I think that the fronts are really overworked..
> That is where I am at and really could use the advice.. :cry:
> Ron
Ron,
When I brought my GMC home from Houston (to Wisconsin) I found my brakes exactly as you describe, I also coasted through a stop light with both feet on the brakes. So the first thing I went for when I got it home was brake upgrade. I did exactly as you described above with a modest improvement in braking, but not what I felt was up to my personal comfort level. On the advice of several on the net, I pulled off the new MC and sensitized booster. I then bought and installed a Power Master system, leaving the rest of the brakes (80mm calipers with performance friction pads, 15/16" rear and 1 1/16" WC's new hoses and carbon metallic shoes) alone. Now....on my coach...the PM made all the difference!! It now stops like a Modern PU truck with only a light touch on the brake pedal.
Here is a list of the Autos that this was available on:
MODELS AFFECTED:
1985 REGAL 3.8L TURBO (ENGINE VIN CODE 9) AND RPO LM9 BRAKES
1986-87 REGAL 3.8L TURBO (ENGINE VIN CODE 7)
1986 LESABRE AND ELECTR ESTATE WAGON
1986 CHEVROLET CAPRICE STATION WAGON
1986 PONTIAC PARISIENNE WAGON
1986 OLDSMOBILE CUSTOM CRUISER STATION WAGON
Part # for Buick Regal Turbo is 52-9702. Part # for the others is 52-9700.
The 9702 and 9700 are functionaly the same, but for some reason the 9700 is considerably cheaper.
You can find this at Autozone. Just pick one of the Station wagons above, create it as one of your vehicles at the AZ web site and search for it under brake parts, or search using the part #.
FWIW, this is where I found it:
http://tinyurl.com/yhds7se
At $440.00 it's not cheap, but was a fairly easy install. While this solution has worked well for me, there are some that would not do this. I would encourage those that see the disadvantages to using the PM, to post their reasons. I am *not* offended by this. Those interested in doing this need to know *everything* about what they are getting themselves into.
So...JWID
--
Larry :)
78 Royale w/500 Caddy
Menomonie, WI.
_______________________________________________
GMCnet mailing list
List Information and Subscription Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
_______________________________________________
GMCnet mailing list
List Information and Subscription Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
Larry Davick
A Mystery Machine
1976(ish) Palm Beach
Fremont, Ca
Howell EFI + EBL + Electronic Dizzy
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| Re: [GMCnet] Rear Disk Brakes [message #64164 is a reply to message #64163] |
Fri, 13 November 2009 15:02 |
Mr ERFisher
Messages: 7117
Registered: August 2005
Karma: 2
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Senior Member |
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here are 365 pages to read
http://gmcmotorhome.info/powermaster.html
larry was supposed to up date this, but--------
too much theater I think ;>)
gene
On Fri, Nov 13, 2009 at 12:49 PM, Larry Davick <ljdavick@comcast.net> wrote:
> Larry,
>
> Was the Power Master a simple bolt-on + wiring?
>
> I have those beautiful stainless brake lines from Tom Hampton, as well as
> larger front rotors, but my brakes are sometimes a two footed affair. I
> simply don't have the budget to go with what I want - Chuck's reaction arm
> set up. I saw the mock-up at Jim K's place and after scratching my head all
> afternoon I finally "got it!" Now I wish I had it...
>
> I just know that I should search Gene's site, as there is probably a
> detailed discussion as to what to do, but I'm eating lunch at work, and I'm
> lazy!
>
> Thanks,
>
> Larry Davick
> The Mystery Machine
>
> ----- Original Message -----
> From: "Larry" <weidnerl@wwt.net>
> To: gmclist@temp.gmcnet.org
> Sent: Friday, November 13, 2009 12:09:48 PM GMT -08:00 US/Canada Pacific
> Subject: Re: [GMCnet] Rear Disk Brakes
>
>
>
> Ron wrote on Fri, 13 November 2009 11:34
> > Hi All..
> > Lots of really good info...
> > I should have mentioned what I have already done...
> > 80 mm Front Calipers
> > Sensitized Brake booster (Twice it was changed due to poor brakes)
> > New Master Cyl. (3 times due to replacements leaking)
> > All New Brake flex hoses all wheels
> > New Combo Valve
> > Auxiliary vacuum pump (really needed here at high altitude)
> > All new rear wheel cyls.. In 2 different sizes as recommend)
> > All new shoes.
> > So I think I have been down the proper upgrade path but still brakes
> suck! I almost wrecked the coach on I25 on the way to the Pueblo rally.
> > I wanted to do the rear disks as I tow a vehicle with a brake buddy (My
> brakes are much better then) And I deal with steep mountain passes all the
> time..
> > The rear disks should dissipate heat much better from the downhill side
> of the passes..
> > A Power Master electrical system was mentioned.. Where is that
> available.. Any place I have looked they are NLA. This is something I have
> also looked at..
> > Again.. I am not trying to reinvent the wheel (or the brakes in my case)
> But none of the normal stuff has helped..
> > Oh and yes I have pressure bled, Gravity bled and adjusted them a hundred
> times.. But the brakes still suck! I have even tried a set of Jim's "Yellow"
> pads.. I wore them in about 6000 miles.. I think that the fronts are really
> overworked..
> > That is where I am at and really could use the advice.. :cry:
> > Ron
>
>
> Ron,
> When I brought my GMC home from Houston (to Wisconsin) I found my brakes
> exactly as you describe, I also coasted through a stop light with both feet
> on the brakes. So the first thing I went for when I got it home was brake
> upgrade. I did exactly as you described above with a modest improvement in
> braking, but not what I felt was up to my personal comfort level. On the
> advice of several on the net, I pulled off the new MC and sensitized
> booster. I then bought and installed a Power Master system, leaving the rest
> of the brakes (80mm calipers with performance friction pads, 15/16" rear and
> 1 1/16" WC's new hoses and carbon metallic shoes) alone. Now....on my
> coach...the PM made all the difference!! It now stops like a Modern PU truck
> with only a light touch on the brake pedal.
>
> Here is a list of the Autos that this was available on:
>
> MODELS AFFECTED:
> 1985 REGAL 3.8L TURBO (ENGINE VIN CODE 9) AND RPO LM9 BRAKES
> 1986-87 REGAL 3.8L TURBO (ENGINE VIN CODE 7)
> 1986 LESABRE AND ELECTR ESTATE WAGON
> 1986 CHEVROLET CAPRICE STATION WAGON
> 1986 PONTIAC PARISIENNE WAGON
> 1986 OLDSMOBILE CUSTOM CRUISER STATION WAGON
>
> Part # for Buick Regal Turbo is 52-9702. Part # for the others is 52-9700.
>
> The 9702 and 9700 are functionaly the same, but for some reason the 9700 is
> considerably cheaper.
>
> You can find this at Autozone. Just pick one of the Station wagons above,
> create it as one of your vehicles at the AZ web site and search for it under
> brake parts, or search using the part #.
>
> FWIW, this is where I found it:
> http://tinyurl.com/yhds7se
>
> At $440.00 it's not cheap, but was a fairly easy install. While this
> solution has worked well for me, there are some that would not do this. I
> would encourage those that see the disadvantages to using the PM, to post
> their reasons. I am *not* offended by this. Those interested in doing this
> need to know *everything* about what they are getting themselves into.
>
> So...JWID
> --
> Larry :)
> 78 Royale w/500 Caddy
> Menomonie, WI.
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
--
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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List Information and Subscription Options:
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| Re: [GMCnet] Rear Disk Brakes [message #64171 is a reply to message #64164] |
Fri, 13 November 2009 16:30 |
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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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365? We should make a calendar!
Thanks, Gene - I've got some reading to do once I get home.
I wish I was able to go to the Port Costa rally this weekend, alas.
Larry Davick
The Mystery Machine
----- Original Message -----
From: "Mr.erf ERFisher" <mr.erfisher@gmail.com>
To: gmclist@temp.gmcnet.org
Sent: Friday, November 13, 2009 1:02:43 PM GMT -08:00 US/Canada Pacific
Subject: Re: [GMCnet] Rear Disk Brakes
here are 365 pages to read
http://gmcmotorhome.info/powermaster.html
larry was supposed to up date this, but--------
too much theater I think ;>)
gene
On Fri, Nov 13, 2009 at 12:49 PM, Larry Davick <ljdavick@comcast.net> wrote:
> Larry,
>
> Was the Power Master a simple bolt-on + wiring?
>
> I have those beautiful stainless brake lines from Tom Hampton, as well as
> larger front rotors, but my brakes are sometimes a two footed affair. I
> simply don't have the budget to go with what I want - Chuck's reaction arm
> set up. I saw the mock-up at Jim K's place and after scratching my head all
> afternoon I finally "got it!" Now I wish I had it...
>
> I just know that I should search Gene's site, as there is probably a
> detailed discussion as to what to do, but I'm eating lunch at work, and I'm
> lazy!
>
> Thanks,
>
> Larry Davick
> The Mystery Machine
>
> ----- Original Message -----
> From: "Larry" <weidnerl@wwt.net>
> To: gmclist@temp.gmcnet.org
> Sent: Friday, November 13, 2009 12:09:48 PM GMT -08:00 US/Canada Pacific
> Subject: Re: [GMCnet] Rear Disk Brakes
>
>
>
> Ron wrote on Fri, 13 November 2009 11:34
> > Hi All..
> > Lots of really good info...
> > I should have mentioned what I have already done...
> > 80 mm Front Calipers
> > Sensitized Brake booster (Twice it was changed due to poor brakes)
> > New Master Cyl. (3 times due to replacements leaking)
> > All New Brake flex hoses all wheels
> > New Combo Valve
> > Auxiliary vacuum pump (really needed here at high altitude)
> > All new rear wheel cyls.. In 2 different sizes as recommend)
> > All new shoes.
> > So I think I have been down the proper upgrade path but still brakes
> suck! I almost wrecked the coach on I25 on the way to the Pueblo rally.
> > I wanted to do the rear disks as I tow a vehicle with a brake buddy (My
> brakes are much better then) And I deal with steep mountain passes all the
> time..
> > The rear disks should dissipate heat much better from the downhill side
> of the passes..
> > A Power Master electrical system was mentioned.. Where is that
> available.. Any place I have looked they are NLA. This is something I have
> also looked at..
> > Again.. I am not trying to reinvent the wheel (or the brakes in my case)
> But none of the normal stuff has helped..
> > Oh and yes I have pressure bled, Gravity bled and adjusted them a hundred
> times.. But the brakes still suck! I have even tried a set of Jim's "Yellow"
> pads.. I wore them in about 6000 miles.. I think that the fronts are really
> overworked..
> > That is where I am at and really could use the advice.. :cry:
> > Ron
>
>
> Ron,
> When I brought my GMC home from Houston (to Wisconsin) I found my brakes
> exactly as you describe, I also coasted through a stop light with both feet
> on the brakes. So the first thing I went for when I got it home was brake
> upgrade. I did exactly as you described above with a modest improvement in
> braking, but not what I felt was up to my personal comfort level. On the
> advice of several on the net, I pulled off the new MC and sensitized
> booster. I then bought and installed a Power Master system, leaving the rest
> of the brakes (80mm calipers with performance friction pads, 15/16" rear and
> 1 1/16" WC's new hoses and carbon metallic shoes) alone. Now....on my
> coach...the PM made all the difference!! It now stops like a Modern PU truck
> with only a light touch on the brake pedal.
>
> Here is a list of the Autos that this was available on:
>
> MODELS AFFECTED:
> 1985 REGAL 3.8L TURBO (ENGINE VIN CODE 9) AND RPO LM9 BRAKES
> 1986-87 REGAL 3.8L TURBO (ENGINE VIN CODE 7)
> 1986 LESABRE AND ELECTR ESTATE WAGON
> 1986 CHEVROLET CAPRICE STATION WAGON
> 1986 PONTIAC PARISIENNE WAGON
> 1986 OLDSMOBILE CUSTOM CRUISER STATION WAGON
>
> Part # for Buick Regal Turbo is 52-9702. Part # for the others is 52-9700.
>
> The 9702 and 9700 are functionaly the same, but for some reason the 9700 is
> considerably cheaper.
>
> You can find this at Autozone. Just pick one of the Station wagons above,
> create it as one of your vehicles at the AZ web site and search for it under
> brake parts, or search using the part #.
>
> FWIW, this is where I found it:
> http://tinyurl.com/yhds7se
>
> At $440.00 it's not cheap, but was a fairly easy install. While this
> solution has worked well for me, there are some that would not do this. I
> would encourage those that see the disadvantages to using the PM, to post
> their reasons. I am *not* offended by this. Those interested in doing this
> need to know *everything* about what they are getting themselves into.
>
> So...JWID
> --
> Larry :)
> 78 Royale w/500 Caddy
> Menomonie, WI.
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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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Larry Davick
A Mystery Machine
1976(ish) Palm Beach
Fremont, Ca
Howell EFI + EBL + Electronic Dizzy
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| Re: Rear Disk Brakes [message #64183 is a reply to message #64105] |
Fri, 13 November 2009 18:53 |
Larry
Messages: 2875
Registered: January 2004
Location: Menomonie, WI
Karma: 10
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Senior Member |
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| ljdavick wrote on Fri, 13 November 2009 14:49 |
Larry,
Was the Power Master a simple bolt-on + wiring?
I have those beautiful stainless brake lines from Tom Hampton, as well as larger front rotors, but my brakes are sometimes a two footed affair. I simply don't have the budget to go with what I want - Chuck's reaction arm set up. I saw the mock-up at Jim K's place and after scratching my head all afternoon I finally "got it!" Now I wish I had it...
I just know that I should search Gene's site, as there is probably a detailed discussion as to what to do, but I'm eating lunch at work, and I'm lazy!
Thanks,
Larry Davick
The Mystery Machine
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Please keep in mind that the PM is not the answer to all braking problems. It will *NOT* keep the rear axle from locking up on a hard stop (that's what the reaction arm is designed to do) and will not compensate for poor maintance of your fluid. Nor will it keep the brakes from fading if you overdrive the brakes going down a long mountain grade. As a result of the PM's design, it simply applies more pressure...than a stock system can...to the braking system for each pound of pressure that you exert to the brake pedal...giving you a lighter touch, and allowing application of enough pressure when you really hit it hard to...if you want to ...lock up all 6.
Your brake lines *MUST* be in top shape. If you lines are old and rusted, the extra pressure that the PM applies to the system could cause a line to burst...causing you to loose brakes...at a time when you may need brakes the most.
You need an adaptor that takes the place of the vacuum booster. Looks like this....
http://www.gmcmhphotos.com/photos/showphoto.php?photo=4077
You also need to do the following wiring:
http://www.gmcmhphotos.com/photos/showphoto.php?photo=7904
Also the next three photos in that album.
The adaptor use to be available from Marvin Peck, but it is my understanding that he passed away several years ago and nobody has taken this over. (Correct me if I'm wrong)
I am working with a gentleman from the GMC Greater Midwest Classics who use to be a pattern maker. Did it all of his working life and spent some time teaching pattern making. Using Marvin Peck's casting, he and I have redesigned the adaptor and he is in the process of making several patterns with the intention of having it cast...(Provided that there is enough of a demand for the adaptor.) We found a foundry that is willing to to small jobs like this, and may try a couple to see how it pans out.
Stay tuned...hope to have something by next summer.
In the mean time you could make your own...see this...
http://www.gmcmhphotos.com/photos/showgallery.php?cat=4450
Larry
78 Royale w/500 Caddy
Menomonie, WI.
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