Home » Public Forums » GMCnet » Replace Master Cylinder or MC plus Booster?
| Replace Master Cylinder or MC plus Booster? [message #327398] |
Thu, 21 December 2017 19:28  |
Wackster
Messages: 49
Registered: November 2017
Location: Baltimore
Karma: 0
|
Member |
|
|
Seeking part number and source for brake booster and MC assembly, or just the correct booster. Background: When pressure bleeding the brakes following rear axle caliper replacement, I developed a leak at the back of the MC where it meets the booster assembly. I see the booster/MC seal is available for $40ish from several Corvette resto shops, but then age of the MC and booster are unknown and from their appearance, could well be original. I previously bought a new Wagner MC (Part No. MC79821), but am now thinking, for that level of effort, I should replace the booster as well. Just not sure what I'm getting into regarding the Booster replacement. It seems straight forward enough, except for the uncertainty with finding the correct replacement parts. I cannot find a cross for the GM 18001970 or 18002562 booster. No luck at http://gmcmhparts.com. I've read quite a bit of discussion on the topic of the MC mounting bracket and booster seal, but not so much on replacing this entire assembly. Anyone done this?
Jim Wack - 1976 23' Crestmont
Baltimore, Maryland
|
|
|
|
| Re: [GMCnet] Replace Master Cylinder or MC plus Booster? [message #327400 is a reply to message #327398] |
Thu, 21 December 2017 19:34  |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
|
Senior Member |
|
|
Save some time and contact a GMC coach parts supplier for information.
On Thu, Dec 21, 2017 at 5:28 PM, James Wack wrote:
> Seeking part number and source for brake booster and MC assembly, or just
> the correct booster. Background: When pressure bleeding the brakes
> following rear axle caliper replacement, I developed a leak at the back of
> the MC where it meets the booster assembly. I see the booster/MC seal is
> available for $40ish from several Corvette resto shops, but then age of
> the MC and booster are unknown and from their appearance, could well be
> original. I previously bought a new Wagner MC (Part No. MC79821), but am
> now thinking, for that level of effort, I should replace the booster as
> well.
> Just not sure what I'm getting into regarding the Booster replacement.
> It seems straight forward enough, except for the uncertainty with finding
> the
> correct replacement parts. I cannot find a cross for the GM 18001970 or
> 18002562 booster. No luck at http://gmcmhparts.com. I've read quite a
> bit
> of discussion on the topic of the MC mounting bracket and booster seal,
> but not so much on replacing this entire assembly. Anyone done this?
> --
> Wackster - 1976 23' Crestmont
> Baltimore, Maryland
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
--
Jim Kanomata
Applied/GMC, Newark,CA
jimk@appliedairfilters.com
http://www.appliedgmc.com
1-800-752-7502
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
Jim Kanomata
Applied/GMC
jimk@appliedairfilters.com
www.appliedgmc.com
1-800-752-7502
|
|
|
|
| Re: [GMCnet] Replace Master Cylinder or MC plus Booster? [message #327402 is a reply to message #327398] |
Thu, 21 December 2017 19:46 |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
|
Senior Member |
|
|
The booster replacement is not the easiest process, but, involves removing
the bezel on the dash, then the air valves in the dash. This will allow
access to the clip that secures the brake pedal linkage pin to the piston
operating rod as well as the 4 nuts that secure the booster to the
bulkhead. Depending upon the year model. There is also a mounting bracket
that is accessed from under the drivers side hatch that braces the
booster/master cylinder assembly. Sometimes, there is a black, nasty,
sealant that has been applied to the bulkhead that makes removing the
assembly difficult as well. Best advice, refer to the shop manual.
Jim Hupy
Salem, Or
78 GMC ROYALE 403
On Dec 21, 2017 5:29 PM, "James Wack" wrote:
> Seeking part number and source for brake booster and MC assembly, or just
> the correct booster. Background: When pressure bleeding the brakes
> following rear axle caliper replacement, I developed a leak at the back of
> the MC where it meets the booster assembly. I see the booster/MC seal is
> available for $40ish from several Corvette resto shops, but then age of
> the MC and booster are unknown and from their appearance, could well be
> original. I previously bought a new Wagner MC (Part No. MC79821), but am
> now thinking, for that level of effort, I should replace the booster as
> well.
> Just not sure what I'm getting into regarding the Booster replacement.
> It seems straight forward enough, except for the uncertainty with finding
> the
> correct replacement parts. I cannot find a cross for the GM 18001970 or
> 18002562 booster. No luck at http://gmcmhparts.com. I've read quite a
> bit
> of discussion on the topic of the MC mounting bracket and booster seal,
> but not so much on replacing this entire assembly. Anyone done this?
> --
> Wackster - 1976 23' Crestmont
> Baltimore, Maryland
>
> _______________________________________________
> 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
|
|
|
|
| Re: [GMCnet] Replace Master Cylinder or MC plus Booster? [message #327408 is a reply to message #327398] |
Fri, 22 December 2017 01:18 |
 |
USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
|
Senior Member |
|
|
James,
The cup seal between the M/C and booster does not seal fluid in the master cylinder, it keeps vacuum in the booster, keeps brake
fluid from the M/C entering the booster and locates the M/C "tail" in the booster.
If you have fluid coming from in between the M/C and booster the rear seal in the M/C is leaking.
Here are two sources for a master cylinder and booster:
Applied GMC:
http://www.appliedgmc.com/index.itml
Dave Lenzi:
http://www.bdub.net/lenzi/index.html
While you're at it I would suggest you ask about / consider a sensitized booster.
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@list.gmcnet.org] On Behalf Of James Wack
Sent: Friday, December 22, 2017 12:29 PM
To: gmclist@list.gmcnet.org
Subject: [GMCnet] Replace Master Cylinder or MC plus Booster?
Seeking part number and source for brake booster and MC assembly, or just the correct booster. Background: When pressure bleeding
the brakes following rear axle caliper replacement, I developed a leak at the back of the MC where it meets the booster assembly. I
see the booster/MC seal is available for $40ish from several Corvette resto shops, but then age of the MC and booster are unknown
and from their appearance, could well be original. I previously bought a new Wagner MC (Part No. MC79821), but am now thinking, for
that level of effort, I should replace the booster as well.
Just not sure what I'm getting into regarding the Booster replacement. It seems straight forward enough, except for the uncertainty
with finding the correct replacement parts. I cannot find a cross for the GM 18001970 or 18002562 booster. No luck at
http://gmcmhparts.com. I've read quite a bit of discussion on the topic of the MC mounting bracket and booster seal, but not so
much on replacing this entire assembly. Anyone done this?
--
Wackster - 1976 23' Crestmont
Baltimore, Maryland
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
Regards,
Rob M. (USAussie)
The Pedantic Mechanic
Sydney, Australia
'75 Avion - AUS - The Blue Streak TZE365V100428
'75 Avion - USA - Double Trouble TZE365V100426
|
|
|
|
| Re: Replace Master Cylinder or MC plus Booster? [message #327424 is a reply to message #327398] |
Fri, 22 December 2017 14:17 |
Aaron
Messages: 21
Registered: February 2017
Location: Oklahoma
Karma: 0
|
Junior Member |
|
|
There are potential problems with the new MC's that you buy off the shelf - they simply are not made to the same specs they used to be even though part numbers may still be the same. I think this is an item that you should buy from one of the two sources in Rob's link Jim K. at Applied or Dave Lenzi) to avoid complications and possible problems.
Dave and Jim both will also be happy to talk to you about parts and the issues.
78 Royale, rear dinette
|
|
|
|
| Re: Replace Master Cylinder or MC plus Booster? [message #327431 is a reply to message #327398] |
Sat, 23 December 2017 00:06 |
 |
Jerry Sitzlar
Messages: 206
Registered: February 2013
Location: Lenoir City, TN
Karma: 4
|
Senior Member |
|
|
Jim Bounds also sells a sensitized booster outright (no trade in required). I just installed one this past summer and it works great on my coach. I also replaced every component in the brake system except for the original calipers. It took about an hour to replace the booster on my 77 model. It took longer to figure out how to do it without cutting up the dash. It was pretty tight for a 74 yo geezer.
Jerry
Jerry Sitzlar..... 77 Eleganza II, Twin bed, dry bath...... Lenoir City, TN (near Knoxville)
|
|
|
|
Goto Forum:
Current Time: Thu Apr 25 23:47:02 CDT 2024
Total time taken to generate the page: 0.02231 seconds
|
GMCforum
Search
Help
Register
Login
Home
