C3 Vette Registry - The Best Resource on the Net for C3 Vettes! C3 Vette
Forums -> C3 Handling Components
Not Logged In! Login or Register!  Users Online: 15 / Help 
Features  Find C3 Parts on ebay in only 2 or 3 clicks!  | Add YOUR C3 to the Registry

Supporting Vendors
Volunteer Vette Products
Bair's Corvettes
VetteBookStore.com
Mid America Motorworks
CorvetteClothing.com

C3 of the Month
None Current
Enter Yours Today!
Online C3 Show
13
C3s are Registered

Vanity Plates
VET VET
Vet Vet
Featured Links

Buy Now
Corvette: America's Sports Car Yesterday, Today, Tomorrow (Hardcover)
Corvette: America's Sports Car Yesterday, Today, Tomorrow (Hardcover)


How To Rebuild Corvette Rolling Chassis 1963-1982
How To Rebuild Corvette Rolling Chassis 1963-1982


Chevrolet Corvette Restoration Guide
Chevrolet Corvette Restoration Guide


Corvette Magazine - $19.99 for 8 issues
Corvette Magazine
Only $19.99 for 8 issues



| Hide Signatures and Profile Pics

 New Topic New Topic Post Reply Reply New Poll New Poll Search     Search Page [1]  
5/25/12 10:40am - Original Message: 'Master cylinder question'
daveo76
Standard Member
- Send Private Message


Vancouver, WA - USA

Vette(s):
1976 Silver/Firethorn. L48, 4spd. Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.

Joined: 8/25/2005
Posts: 830
The AIM for my car shows a gasket and retaining ring in between the master cylinder and the booster.  Should my new (reman) master have come with those?  I took the old one off months ago and don't remember what I did with them, or if they were even there.  Anyone know where I can get those?  A related question: can I buy the pushrod seal that is tucked inside the booster? I presume that is important in regards to holding vacuum and the old one looks OK, but not great.  Thanks, guys.



____________________________________

 

1976 Silver/Firethorn.  L48, 4spd.  Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.
 Reply Reply  Quote Reply w/Quote
 
Support C3VR!
Suport our advertisers
5/25/12 12:21pm - Reply: 'Re: Master cylinder question'
Adams' Apple Lifetime Member
Lifetime Member
Moderator
- Send Private Message


Duncanville, TX - USA

Vette(s):
#1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas

Joined: 11/8/2003
Posts: 19449
There IS a seal between the master and booster...not sure about a retaining ring. I traced a vacuum leak on my '74 to this seal several years ago. I wound up using/modifying one of my old headlight actuator seals for mine, and I don't know if these seals are available anywhere. There was another discussion about this same issue a while back, and I think I suggested contacting someone who actually rebuilds the boosters to see if the seals were available.

|UPDATED|5/25/2012 9:21:23 AM (AZT)|/UPDATED|


____________________________________
Joel Adams
C3VR Lifetime Member #56    
My Link


(click for Texas-sized view!)
             NCRS

"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"
 Reply Reply  Quote Reply w/Quote
5/25/12 10:42pm - Reply: 'Re: Master cylinder question'
Adams' Apple Lifetime Member
Lifetime Member
Moderator
- Send Private Message


Duncanville, TX - USA

Vette(s):
#1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas

Joined: 11/8/2003
Posts: 19449
daveo76 said: Joel, could you check your AIM for me?  The P/N's I'm curious about are: 730392 and 9787620.  I've done some research elsewhere (yep, one of those other forumsErmm) and it sounds like there is a lot of debate about these parts.   From what I've learned, every AIM (at least 68-81) shows them, but many cars did not come with them.  I'm 99% sure mine did not.  As best I can tell, their only purpose is to serve as a backup for vacuum if the seal around the pushrod fails, so maybe they just left them out on many cars.  Would you agree?  I think I'm going to just leave them out and hope for the best.  

BTW, good suggestion on using the headlight actuator boot thingy for the pushrod seal.  I happen to have one of those laying around still in the package so I may try that.  Any further info about how you modded it to make it work?

Any other opinions or experience out there regarding the two parts mentioned above?  Anyone recently replaced a master cyl?  Would love to know if you found a gasket and metal ring between the booster and MC.  

Thanks, guys!  


I'll look and see...I have the '73 and '74 AIM. I'll check the Service Manual, too, just in case there may be something in there...

I don't really remember what I did to get the headlight seal in there, but...best I can recall, the purpose is to seal the master against the booster, as a redundant seal, if the pushrod seal happens to leak. I had had a nagging vacuum leak in mine for years that I just couldn't find, and I finally traced it to the master/booster. Of course, if the pushrod seal weren't leaking to start with, it wouldn't be an issue. All you need is some sort of seal that fits the diameter of the hole in the booster, and is thick enough to seal against the master, without being too thick to allow it to bolt up tight/flat.


____________________________________
Joel Adams
C3VR Lifetime Member #56    
My Link


(click for Texas-sized view!)
             NCRS

"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"
 Reply Reply  Quote Reply w/Quote
5/26/12 12:29am - Reply: 'Re: Master cylinder question'
daveo76
Standard Member
- Send Private Message


Vancouver, WA - USA

Vette(s):
1976 Silver/Firethorn. L48, 4spd. Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.

Joined: 8/25/2005
Posts: 830
Thanks, Joel.  I think I may have came up with a solution.  I had a coffee can full of misc plumbing washers and O-rings.  I used one of those reddish ones with flat sides and put it in the machined groove on the M/C.  Then, since it still wasn't really snug in the booster, I butted up a black o-ring type against that washer and it's an obvious snug fit now.  Since it's only a backup for the pushrod seal it should be fine.

Next question: the instructions that came with the M/C talk about bench bleeding.  Is that really necessary if I'm going to bleed all four wheels?


____________________________________

 

1976 Silver/Firethorn.  L48, 4spd.  Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.
 Reply Reply  Quote Reply w/Quote
5/26/12 10:51am - Reply: 'Re: Master cylinder question'
Adams' Apple Lifetime Member
Lifetime Member
Moderator
- Send Private Message


Duncanville, TX - USA

Vette(s):
#1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas

Joined: 11/8/2003
Posts: 19449
Upon further investigation, I have determined that the "gasket" in the AIM is really called an air filter. It is not rubber, but more of a felt type material...it's purpose is to keep dirt/crud out of the space between the master and booster. It does actually fit into the groove on the end of the master, where you say you put your o-ring. Thumbs Up
The Service manual does NOT cover rebuild/service of the master cyl, but it does cover rebuild of the booster. It also shows a very nice cut-a-way of the booster/master, which plainly shows the "air filter".
My memory of original cars is that the felt-like "seal" is usually crumbles by the time the master is removed for service, and never replaced. The "retainer" noted in the AIM is, if I remember correctly, just a piece of cardboard-like material, to keep the felt from being bent out of position on installation of the master. So, basically, the "gasket/seal" is NOT meant to be a backup seal for the booster...just a dam of sorts to keep foreign material out of the space. And now ya know!

Yes..you DO need to bench-bleed the master...regular bleeding of the brake system will NOT get the air out of the master...and ya gotta get that out before you can bleed the rest of the system. Most masters come with hoses and attachment to bench bleed them...if not, you can get a bench-bleed hose/fitting kit at any parts house for very little cash...prolly $5 or so. The "kits" usually have several different sized hoses and plastic fittings.
hth


____________________________________
Joel Adams
C3VR Lifetime Member #56    
My Link


(click for Texas-sized view!)
             NCRS

"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"
 Reply Reply  Quote Reply w/Quote
5/26/12 1:08pm - Reply: 'Re: Master cylinder question'
daveo76
Standard Member
- Send Private Message


Vancouver, WA - USA

Vette(s):
1976 Silver/Firethorn. L48, 4spd. Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.

Joined: 8/25/2005
Posts: 830
Very interesting, Joel!  Thanks for researching it for me.  I think I'll leave my washer/O-ring set-up and call it good.  I might have to invest in a real service manual - my Haynes manual in conjunction with the AIM covers most things, but not all.  

Yep, my M/C came with the fittings and hoses to bench bleed.  Now I know that I have to do that, too.  Thanks for the input.  


____________________________________

 

1976 Silver/Firethorn.  L48, 4spd.  Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.
 Reply Reply  Quote Reply w/Quote
5/26/12 10:51pm - Reply: 'Re: Master cylinder question'
Adams' Apple Lifetime Member
Lifetime Member
Moderator
- Send Private Message


Duncanville, TX - USA

Vette(s):
#1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas

Joined: 11/8/2003
Posts: 19449
Here's the page from the '73 AIM that shows the "gasket" in question. If you'll notice, the gasket is too large to fit up inside of the booster, and sit flat against the seal that is already there. That's what my "modified" headlight seal does...it sits flat against the master end, and the seal of the booster. At least it "fixed" my vacuum leak. Of course now...vacuum is prolly sucking fluid into the booster...LOL

I guess it might help if I actually put the LINK to the page in the post....Wacko

http://www.c3vr.com/member_uploads/4401_4500/4427/mastercyl.jpg


|UPDATED|5/26/2012 7:51:56 PM (AZT)|/UPDATED|


____________________________________
Joel Adams
C3VR Lifetime Member #56    
My Link


(click for Texas-sized view!)
             NCRS

"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"
 Reply Reply  Quote Reply w/Quote
5/27/12 12:53am - Reply: 'Re: Master cylinder question'
daveo76
Standard Member
- Send Private Message


Vancouver, WA - USA

Vette(s):
1976 Silver/Firethorn. L48, 4spd. Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.

Joined: 8/25/2005
Posts: 830
Thanks, Joel.  My AIM looks pretty similar.  I think the mystery has been solved.  I'll probably hook up my vacuum pump to the booster and make sure it holds - if it does it seems like I'll be good.  (At least until that pushrod seal goes out -- if it does I'll know the culprit right away)

____________________________________

 

1976 Silver/Firethorn.  L48, 4spd.  Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.
 Reply Reply  Quote Reply w/Quote
5/30/12 2:09am - Reply: 'Re: Master cylinder question'
daveo76
Standard Member
- Send Private Message


Vancouver, WA - USA

Vette(s):
1976 Silver/Firethorn. L48, 4spd. Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.

Joined: 8/25/2005
Posts: 830
Took me two tries to get a setup that would hold vacuum.  I think my pushrod seal is worn out - first time I relied only on that and would not hold any vacuum.  Then I tried the headlight actuator seal over the pushrod as well as my o-ring setup around the M/C and held just fine.  

Now that that is all squared away tonight the plan was to bleed all four wheels.  No go.  Spent more time dinking around with my "MityVac" vacuum pump and bleeding kit.  Turns out the little (and I mean little) plastic reservoir it comes with is a piece of junk and won't hold any vacuum.  Tomorrow I'm going to build a real reservoir out of a mason jar and brass fittings in the lid.  (Or persuade the wife to sit in the car for an hour or so and pump the brakes).


____________________________________

 

1976 Silver/Firethorn.  L48, 4spd.  Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.
 Reply Reply  Quote Reply w/Quote
5/31/12 8:58pm - Reply: 'Re: Master cylinder question'
crossfire1982
Standard Member
- Send Private Message


Cramerton, NC - USA

Vette(s):
black 1982 coupe slate gray interior, 350 crossfire, 1985 fuel pump, Steeroids R&P conversion

Joined: 8/22/2006
Posts: 1094
Dave, Bleeding brakes is always aggrivating but Russell speed bleeders make the job almost painless. Only one person required and Ive even bled two calipers at the same time. No pumping up and holding just pump the brake pedal slowly and firmly. 
 


|UPDATED|5/31/2012 5:58:36 PM (AZT)|/UPDATED|


____________________________________

Click for a larger image
Save The Wave


 Reply Reply  Quote Reply w/Quote
5/31/12 10:59pm - Reply: 'Re: Master cylinder question'
Adams' Apple Lifetime Member
Lifetime Member
Moderator
- Send Private Message


Duncanville, TX - USA

Vette(s):
#1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas

Joined: 11/8/2003
Posts: 19449
The speed bleeders are kewl. A little tip for using them, tho...carefully put a couple of wraps of teflon tape on the threads before installing them. This will keep them from allowing air into the system thru the threads, while they are loose for bleeding. I've seen some that come with a sealant of some kind on the threads, for the same reason. Wink

Good luck with the bleeding...I have to say, next to standing on my head under the dash, bleeding the brakes is the worst job on one of these things...and I have a pressure bleeder!


____________________________________
Joel Adams
C3VR Lifetime Member #56    
My Link


(click for Texas-sized view!)
             NCRS

"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"
 Reply Reply  Quote Reply w/Quote
6/1/12 1:59am - Reply: 'Re: Master cylinder question'
daveo76
Standard Member
- Send Private Message


Vancouver, WA - USA

Vette(s):
1976 Silver/Firethorn. L48, 4spd. Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.

Joined: 8/25/2005
Posts: 830
Thanks guys.  Last night I put together my "homemade mason jar brake bleeding reservoir" and tonight I had to put some finishing touches on it (as in some more silicone around the brass fittings).  I'm not ready to give up on that method yet, but I am seriously considering buying the speed bleeders!  I'll keep ya posted!  

P.S. My Haynes manual says this order: LR Inner, LR Outer, RR Inner, RR Outer, LF, RF.  Sound OK?  


____________________________________

 

1976 Silver/Firethorn.  L48, 4spd.  Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.
 Reply Reply  Quote Reply w/Quote
6/1/12 7:53pm - Reply: 'Re: Master cylinder question'
corvette440hp Lifetime Member
Lifetime Member
- Send Private Message


Joined: 7/2/2006
Posts: 8205
daveo76 said: Thanks guys.  Last night I put together my "homemade mason jar brake bleeding reservoir" and tonight I had to put some finishing touches on it (as in some more silicone around the brass fittings).  I'm not ready to give up on that method yet, but I am seriously considering buying the speed bleeders!  I'll keep ya posted!  

P.S. My Haynes manual says this order: LR Inner, LR Outer, RR Inner, RR Outer, LF, RF.  Sound OK?  

Not to me..............you do the right front before the left front. Always the furthest away until you finially get to the clostest. That's the way eboEvil Smile taught me.............and I believe in eboThumbs Up

____________________________________
corvette440hp
 Reply Reply  Quote Reply w/Quote
6/2/12 12:18am - Reply: 'Re: Master cylinder question'
daveo76
Standard Member
- Send Private Message


Vancouver, WA - USA

Vette(s):
1976 Silver/Firethorn. L48, 4spd. Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.

Joined: 8/25/2005
Posts: 830
That makes sense to me and almost all non-Corvette references on the 'net seem to agree: furthest from the M/C first (although front to back shouldn't matter since they're on different circuits).  But I double checked my Haynes and found this corroborating reference online:


and they both agree with the "left side first" sequence for '65-'82 Vettes.   Anyone willing to look it up in the shop manual?   

Thanks!  


____________________________________

 

1976 Silver/Firethorn.  L48, 4spd.  Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.
 Reply Reply  Quote Reply w/Quote
6/2/12 11:46am - Reply: 'Re: Master cylinder question'
corvette440hp Lifetime Member
Lifetime Member
- Send Private Message


Joined: 7/2/2006
Posts: 8205
daveo76 said: That makes sense to me and almost all non-Corvette references on the 'net seem to agree: furthest from the M/C first (although front to back shouldn't matter since they're on different circuits).  But I double checked my Haynes and found this corroborating reference online:


and they both agree with the "left side first" sequence for '65-'82 Vettes.   Anyone willing to look it up in the shop manual?   

Thanks!  

Dave, the information in my shop manual (GM 1974 Sevice Manual) Says to bleed the the caliper NEAREST to the master cylinder FIRST, then the further out one. On a disc brake car while PRESSURE bleeding the book reads to hold open the proportioning valve with a tool J-23709
The manual reads "It is advisable to bleed one valve at a time to avoid allowing fluid level in resivoir to become dangerously low. The correct sequence is to bleed the valve, either front or rear system, nearest master cylinder first. This sequence expels air from lines and calipers or wheel cylinders nearest to the master cylinder first and eliminates the possibility that air in a line close to the master cylinder may enter a line farther away after it has been bled."
WOW, somehow my insticts must have been working. Two weeks ago I bench bled my new SSBC master cylinder. I then installed it on my power booster in the car. I then began bleeding the nearest caliper the (left) driver's side inboard bleeder. While doing this the outboard bleeder was spewing brake fluid. It is the Russell check valve style. The calipers are brand new SSBC 48mm 4 piston. I checked the inside seat, which looked ok. I then installed the original SSBC bleeder, which also spewed fluid. I'm using Silicone (Dot 5) fluid, which really doesn't matter. I contacted SSBC tech dept. to have the goofus tell me to tighten the bleeder more. What a joke. I finially connected with the sales dept. I spoke with a great guy. Long story-short he shot out a new caliper that I got on Wednesday. I painted it with three coats of VHT brake caliper blue paint and then one coat of clear. I expidited the drying between coats with a heat gun. Thursday I baked the whole caliper in mama's oven (she wasn't home) at 200 degrees for 20 minutes. I haven't put the caliper on yet. So this GM service manual WILL be the way that I finish the brake bleeding. Again, for some reason I started with the front driver side, which turns out right according to the manual. I hope this helps you with your project...............and GOOD LUCK to you.............You seem very meticulous, and that's the RIGHT WAY TO BE! You also really want to check on facts. I have to check the book a bit more before I just wing it. Keep us informed as to how it's going.

____________________________________
corvette440hp
 Reply Reply  Quote Reply w/Quote
6/4/12 1:11am - Reply: 'Re: Master cylinder question'
daveo76
Standard Member
- Send Private Message


Vancouver, WA - USA

Vette(s):
1976 Silver/Firethorn. L48, 4spd. Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.

Joined: 8/25/2005
Posts: 830
Thanks for the compliment!  I'm trying to be meticulous, but I've made plenty of mistakes along the way, too.  Fortunately the big thing I've learned from all those is to not rush into things without researching them first.  Like this brake thing.  So far, my "sucking method" well....sort of sucks.  I still have a soft pedal that goes all the way to the floor but with no obvious leaks.  I'm going to bug the wife tomorrow night to sit out in the garage and do some pedal pushing for me and see if I can firm things up that way.  And I still may spring for those speed bleeders, too.  Thanks again for the help and confirming that my Haynes manual is indeed correct according to the General.  

____________________________________

 

1976 Silver/Firethorn.  L48, 4spd.  Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.
 Reply Reply  Quote Reply w/Quote
6/4/12 6:14pm - Reply: 'Re: Master cylinder question'
corvette440hp Lifetime Member
Lifetime Member
- Send Private Message


Joined: 7/2/2006
Posts: 8205
Thank you Dave for making me go back to the manualThumbs Up. I just installed my new SSBC caliper, on the left front. NOW FOR THE FUN PART. Can I borrow your wife to push the brake peddle? Just kiddingClown I could use mine, but I have the Russell Check valve ones.  

____________________________________
corvette440hp
 Reply Reply  Quote Reply w/Quote
 New Topic New Topic Post Reply Reply New Poll New Poll Search     Search Page [1]  
 Forums -> C3 Handling Components
(Moderator: Adam Wartell, Norsky, Adams' Apple)
 

 
Official C3 Vette Registry Community:
Home | Forums | Email | Who's Online | Clubs | Events | Member Stats

Other Official C3 Vette Registry Areas:
Members | Research | Shop | My Account | About C3VR
 

Corvette is a registered trademark of the General Motors Corporation(GM) & Chevrolet Motor Division. Vette Registries, LLC is responsible for all site content (except for member submitted content or where otherwise noted) and does not claim or imply that Chevrolet or GM is responsible for Official C3 Vette Registry content. Vette Registries, LLC is independent from GM and is not affiliated with, sponsored or supported by GM.  Copyright/trademark/sales mark infringements are not intended, or implied and are in fact used to support GM, Chevrolet and Corvette

Official C3 Vette Registry content is Copyright 2001-2017, Vette Registries, LLC. Content may not be reused without written consent. All Rights Reserved. NS

Corvette (Vette) Model Years on this site: 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 30