Booster Replacement

R

robert mueller

New member
Jul 4, 2007
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G'day,

I am going to be replacing the booster in the Kingsley with one of Dave Lenzi's sensitized boosters. I vaguely remember reading
something about it being a PITA on a coach that does not have the PowerLevel system as the access to the nuts on the cockpit side of
the firewall are impossible to reach. I also remember someone noting that they cut a BIG hole in the lower part of the dashboard to
make the access easier. Can anyone provide any info about where to cut the hole, how big to make the hole, and the tool used to cut
the hole. A photo would be most helpful.

Regards,
Rob M.
The Pedantic Mechanic
Sydney, Australia
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
USA '77 Kingsley - TZE 267V100808
 
 
Rob,
See the following:

http://www.gmcmhphotos.com/photos/bob-dunahugh/p60045-brake-booster-nuts-in-2777-and-2778-gmcs.html

http://www.gmcmhphotos.com/photos/bob-dunahugh/p60044-brake-booster-nuts-in-2777-and-2778-gmcs.html

JR

>
> G'day,
>
> I am going to be replacing the booster in the Kingsley with one of Dave Lenzi's sensitized boosters. I vaguely remember reading
> something about it being a PITA on a coach that does not have the PowerLevel system as the access to the nuts on the cockpit side of
> the firewall are impossible to reach. I also remember someone noting that they cut a BIG hole in the lower part of the dashboard to
> make the access easier. Can anyone provide any info about where to cut the hole, how big to make the hole, and the tool used to cut
> the hole. A photo would be most helpful.
>
> Regards,
> Rob M.
> The Pedantic Mechanic
> Sydney, Australia
> AUS '75 Avion - The Blue Streak TZE365V100428
> USA '75 Avion - Double Trouble TZE365V100426
> USA '77 Kingsley - TZE 267V100808
>
>
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
 
That is pretty much the same method my neighbor mechanic used to install my Lenzi brake booster a few weeks ago.

D C "Mac" Macdonald
Amateur Radio K2GKK
Since 30 November '53
USAF and FAA, Retired
Member GMCMI & Classics
Oklahoma City, OK
"The Money Pit"
TZE166V101966
'76 ex-Palm Beach
k2gkk + hotmail dot com

________________________________
From: Gmclist on behalf of John Wright
Sent: Thursday, November 16, 2017 11:45
To: gmclist
Subject: Re: [GMCnet] Booster Replacement

Rob,
See the following:

https://nam03.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.gmcmhphotos.com%2Fphotos%2Fbob-dunahugh%2Fp60045-brake-booster-nuts-in-2777-and-2778-gmcs.html&data=02%7C01%7Ck2gkk%40hotmail.com%7C8d791e367b734d9ae74208d52d19f97c%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636464511934068392&sdata=2%2BVyz1XaNuXPvhGu4tSyvzh8wtiz%2BP0J7GehTDYr6OE%3D&reserved=0

https://nam03.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.gmcmhphotos.com%2Fphotos%2Fbob-dunahugh%2Fp60044-brake-booster-nuts-in-2777-and-2778-gmcs.html&data=02%7C01%7Ck2gkk%40hotmail.com%7C8d791e367b734d9ae74208d52d19f97c%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636464511934068392&sdata=o50wyu3kRzakU8d8gWq6kauJYFcXo4iW3txVxxf2nSU%3D&reserved=0

JR

>
> G'day,
>
> I am going to be replacing the booster in the Kingsley with one of Dave Lenzi's sensitized boosters. I vaguely remember reading
> something about it being a PITA on a coach that does not have the PowerLevel system as the access to the nuts on the cockpit side of
> the firewall are impossible to reach. I also remember someone noting that they cut a BIG hole in the lower part of the dashboard to
> make the access easier. Can anyone provide any info about where to cut the hole, how big to make the hole, and the tool used to cut
> the hole. A photo would be most helpful.
>
> Regards,
> Rob M.
> The Pedantic Mechanic
> Sydney, Australia
> AUS '75 Avion - The Blue Streak TZE365V100428
> USA '75 Avion - Double Trouble TZE365V100426
> USA '77 Kingsley - TZE 267V100808
>
>
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> https://nam03.safelinks.protection.outlook.com/?url=http%3A%2F%2Flist.gmcnet.org%2Fmailman%2Flistinfo%2Fgmclist_list.gmcnet.org&data=02%7C01%7Ck2gkk%40hotmail.com%7C8d791e367b734d9ae74208d52d19f97c%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636464511934068392&sdata=ktAJElWB2Jfoh26fDR17XZFDRsuz%2F7wAArBbtVby%2BCg%3D&reserved=0

_______________________________________________
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Unsubscribe or Change List Options:
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The top nut on the passenger side requires the use of a wide range of cuss words, especially getting the washers back in place and the nut started on
the threads.

Anyone know if the bracket on the master cylinder is even required? I've never seen one on any other vehicle.
--
Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.
Hubler 1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that
 
Rob,
I put one of Daves in 6 months ago.
I can come by and help you if you would like.
Scott.
--
Scott Nutter
1978 Royale Center Kitchen, Patterson 455, switch pitch tranny, 3.21 final drive, Quad bags, tankless water heater, everything Lenzi.
Houston, Texas
 
> Some dashes can be flexed, and the correct small hands can get those nuts without cutting.
>
> A thin ratchet wrench is needed. I use a craftsman ratchet wrench.

I replaced mine quite a few years ado WITHOUT cutting a hole. It was a lot of fun getting in there with just about every small wrench I own but it is
possible. I am NOT PowerLevel. Mine is Electro level I
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
 
Yes, you definitely need the brace. Otherwise you eventually will stress crack the metal where the booster is mounted.

Emery Stora

>
> The top nut on the passenger side requires the use of a wide range of cuss words, especially getting the washers back in place and the nut started on
> the threads.
>
> Anyone know if the bracket on the master cylinder is even required? I've never seen one on any other vehicle.
> --
> Bruce Hislop
> ON Canada
> 77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.
> Hubler 1 ton front end
> http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
> My Staff says I never listen to them, or something like that
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
 
I know that I had success using a racheting box end wrench and a lot of patience.
I was able to get at from the side and flexing the dash .
Dave’s sensitized booster has been a big plus for our coach. Especially with mountain driving ing the west.

Gary Coaster / Reno, NV
1977 GMC Eleganza ll
GMC RV Day Night Shade Sales
GMCShades
www.GMCMotorhomemarketplace.com/GMC_Shades/

>

>> Some dashes can be flexed, and the correct small hands can get those nuts without cutting.
>>
>> A thin ratchet wrench is needed. I use a craftsman ratchet wrench.
>
> I replaced mine quite a few years ado WITHOUT cutting a hole. It was a lot of fun getting in there with just about every small wrench I own but it is
> possible. I am NOT PowerLevel. Mine is Electro level I
> --
> Ken Burton - N9KB
> 76 Palm Beach
> Hebron, Indiana
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
 
I haven't had to do that job on a 77+, but, I'd guess that if that
ratcheting box end were one of those with the "broken back", it would make
the task a lot easier -- you can get into 'most anywhere with those.

Ken H.

> I know that I had success using a racheting box end wrench and a lot of
> patience.
> I was able to get at from the side and flexing the dash .
> Dave’s sensitized booster has been a big plus for our coach. Especially
> with mountain driving in the west.
>
​...​
 
Early coaches with the air knobs in the dash, can be accessed by removing
that panel. Later coaches with the rocker switches to the left side of the
drivers left elbow can be accessed by removing the heater control assembly.
I usually drill a 2" hole in the lower dash with a hole saw in line with
the lower left nut, and reach in with a socket and long extension. Assembly
, I use sticky body sealant (dum dum) putty to stick the nut to the socket.
Jim Hupy

> I haven't had to do that job on a 77+, but, I'd guess that if that
> ratcheting box end were one of those with the "broken back", it would make
> the task a lot easier -- you can get into 'most anywhere with those.
>
> Ken H.
>
>

>
> > I know that I had success using a racheting box end wrench and a lot of
> > patience.
> > I was able to get at from the side and flexing the dash .
> > Dave’s sensitized booster has been a big plus for our coach. Especially
> > with mountain driving in the west.
> >
> ​...​
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
 
Rob,

I replaced the booster on my 77 Eleganza this past summer. I did not make any cuts to the outside of the dash, only a very small cut underneath where
it is not visible. It was easy peasy. Tomorrow I'll try to take pics.

Jerry
--
Jerry Sitzlar..... 77 Eleganza II, Twin bed, dry bath......
Lenoir City, TN
 
G'day,

Thanks guys!

Regards,
Rob M.
The Pedantic Mechanic
Sydney, Australia
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
USA '77 Kingsley - TZE 267V100808
 
Emery,

Spot on!

When the M/C in Double Trouble started "playing up" I had Helen push on the brakes with the engine running to see what was going on.

I watched the M/C to see where it was leaking and was surprised to see the booster moving when she pushed the pedal. The brace was
installed; however, the rivnuts in the dash had come out and someone used lag bolts to hold it to the bottom of the dash!

I got some steel rivnuts that look like Molly bolts from McMaster-Carr and installed them in the bottom of the dash. I used epoxy on
them to make sure they wouldn't turn when the bracket retaining bolts were installed.

That was back in 2008 and so far so good.

Regards,
Rob M.
The Pedantic Mechanic
Sydney, Australia
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
USA '77 Kingsley - TZE 267V100808


-----Original Message-----
From: Gmclist [mailto:gmclist-bounces] On Behalf Of Emery Stora
Sent: Thursday, November 16, 2017 3:46 PM
To: gmclist
Subject: Re: [GMCnet] Booster Replacement

Yes, you definitely need the brace. Otherwise you eventually will stress crack the metal where the booster is mounted.

Emery Stora
 
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