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65/66 Single/Dual Master Cylinder?

Old 10-14-2006, 12:55 PM
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62Jeff
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Default 65/66 Single/Dual Master Cylinder?

A quick question, one that doesn't involve wiring for a change.

I see references to single and dual master cylinders for 65 versus 66 vettes.

Does that mean that the 65 has brake lines that both run from the master cylinder to a single junction point thus ensuring the rear brakes and front brakes all lose their pressure if anything goes wrong? And does that mean the 66 has a completely divorced brake line setup for front to rear?

Jeff
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Old 10-14-2006, 12:58 PM
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vintagecorvette
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The dual MC was only available on PB cars. THe AIM shows a photo of the lines, does it not?

oWEN
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Old 10-14-2006, 01:04 PM
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macdarren
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Originally Posted by 62Jeff
A quick question, one that doesn't involve wiring for a change.

I see references to single and dual master cylinders for 65 versus 66 vettes.

Does that mean that the 65 has brake lines that both run from the master cylinder to a single junction point thus ensuring the rear brakes and front brakes all lose their pressure if anything goes wrong? And does that mean the 66 has a completely divorced brake line setup for front to rear?

Jeff

This is true for the 67 totally separate, the 65 is also true totally connected all or nothing. The 66....I don't know, I think it used different setups for power vs manual..I always thought the 66 had the all or nothing set up for manual very like the 65 but with slightly different line routing.....but a 66 expert will know better than I.
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Old 10-14-2006, 01:06 PM
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My 65 has separate lines that appear to separate the front and rear brakes. Yes, a quick check of the AIM confirms there does not appear to be a single junction point for front/rear lines.

I do not trust that I have a 65 frame on my car.

People post here about converting their 65 to a 66 dual-line setup.

I wondered what the benefit is to the 66 system.
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Old 10-14-2006, 01:17 PM
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JohnZ
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'65-'66 manual brake cars had a single-reservoir master cylinder and one outlet that served the entire brake system.

'65-'66 power brake cars had a dual-reservoir/dual-circuit master cylinder with two separate outlets - one fed the front system, one fed the rear system.

Starting in '67, all Corvettes (manual or power) had dual-reservoir/dual-circuit master cylinders with dual outlets and two separate hydraulic systems.

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Old 10-14-2006, 01:26 PM
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Excellent John, thank you!
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Old 10-14-2006, 02:05 PM
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Originally Posted by 62Jeff

People post here about converting their 65 to a 66 dual-line setup.

I wondered what the benefit is to the 66 system.

In 1966 the front to rear brake line changed from 3/16th" to 1/4". Some of my catalogs state that this change occured in the late production '65 model. In 1966 they routed the brake line along the bottom of the frame so you can change it without lifting the body.


'66 brake line routing................


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Old 10-15-2006, 12:17 AM
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Originally Posted by JohnZ
'65-'66 manual brake cars had a single-reservoir master cylinder and one outlet that served the entire brake system.

'65-'66 power brake cars had a dual-reservoir/dual-circuit master cylinder with two separate outlets - one fed the front system, one fed the rear system.

Starting in '67, all Corvettes (manual or power) had dual-reservoir/dual-circuit master cylinders with dual outlets and two separate hydraulic systems.

I'm working on a conversion on my 65 manual brakes to dual. I had to get the 65 power brake lines & front block and 67 manual dual master cylinder, both from Long Island Corvette. I replaced the MC rear line while I had the body off the frame, but I like the idea of the 66 line also previously posted.
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Old 10-15-2006, 02:31 AM
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Downdraft
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Here is a picture of what I have in my '65. From what I read and the pictures I've seen it seems to be an add on.

During this winter, when I restore the car I will have the calipers redone, (I didn't look for a rebuild kit yet but am sure one is readily available) probably new pads,, we stainless steel hoses to the calipers. The only thing that I had to get used to is that the brake pedal, compared to all my other cars is about 1 to 2 inches higher - when moving your foot from the gas pedal to the brake pedal.


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Old 10-15-2006, 10:15 AM
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Curious to see if anyone responds to your pic as well as I have an early on '65 (Nov. 4 '64 born on date) w/power brakes as well and I don't think mine's correct for my car...but I'll be darned if I can find anything to tell me otherwise.
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Old 10-15-2006, 11:07 AM
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Downdraft -- yes, somebody has done a conversion on your car. That is a later model master cylinder. My guess is that it's from a C3 Vette, the '67 MC didn't have the bleeder screws on it. If you want to make it correct, you'd have to install a '65 single master cylinder and plumb everything to the single outlet. Personally, I'd leave it alone, the dual cylinder is much safer. By the way, the hose clamp on the steering column isn't correct either.

Spaceboy -- if your MC looks like Downdrafts picture, you also have an incorrect MC. The '65 power brakes have a dual MC, but it looks quite different. It has two large plastic twist-off caps for the reservoirs.
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Old 10-15-2006, 01:25 PM
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I did the changeover on my 65 to a 67 MC and it does have the bleeders on the cylinder. Think it's the other way around that later dual MCs don't have bleeders. Not a big deal cause I REALLY like driving with a split system rather than the one does all (or fails all)

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Old 10-15-2006, 02:24 PM
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Yep...mine definitely is like Downdraft's. On the side of the MC it has the number 5455509 which from what I know seems tied to a '67 in terms of being correct for that year. Which leads to an additional question...assuming I am able to find an original MC with the dual reservoirs, I'm assuming I'd also be needing to find the vacuum boost/power assist unit as well, correct? In other words, did all '65's with power brakes come with a two-part system...the MC and the vacuum boost/power assist unit? I see two holes that go into the wiper vent area (if you will) that are currently unused that I'd guess play a part of bolting the vacuum unit on.

If anyone's interested in my 5455509 MC let me know as I'll be swapping mine out as soon as I can find a 5467084 MC...

Last edited by spaceboyusa; 10-15-2006 at 02:50 PM.
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Old 10-15-2006, 05:47 PM
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67's were unique, as both manual and power brakes used exactly the same master cylinder (casting #5455509, stamped "DC", bail-tagged "YA", 1" bore, "deep" hole in the rear piston, bleeders above the outlet ports); here's a photo of a stock '67 manual brake setup:



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Old 10-15-2006, 05:49 PM
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Originally Posted by spaceboyusa
I see two holes that go into the wiper vent area (if you will) that are currently unused that I'd guess play a part of bolting the vacuum unit on.
Those two holes are for the two bolts that attach the top brackets on the booster - they go through the firewall into threads on an anchor plate that's riveted to the back side of the panel.
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Old 10-15-2006, 08:10 PM
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Unless you are into absolute originality, I am a big beliver in dual MC setup, that way if one brake line gets damaged/loses pressure, you aren't brakeless.

Saves you from having to do a crash downshift into first, turn off the ignition and pull on the e-break as far as it will go and hope it all works. (hit a muffler once, in another car,a nd the muffler kicked up and cut the rear brake hose, ruined rear tire also)

Doug

Last edited by AZDoug; 10-15-2006 at 08:13 PM.
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Old 10-19-2014, 05:53 PM
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Default Dual MC for 66

Does anyone have a recommendation on where to purchase a dual MC kit for a 66?
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Old 10-19-2014, 06:57 PM
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Originally Posted by 67 seeker View Post
Does anyone have a recommendation on where to purchase a dual MC kit for a 66?
Here you go from Corvette Stainless Steel Brakes, Inc.: http://www.cssbinc.com/1965-66corvet...twithdisc.aspx

Thomas
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Old 10-19-2014, 07:01 PM
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Yes I did see that they provide them as per searching the threads. Any issues? Extra parts?
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Old 10-20-2014, 10:58 AM
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Originally Posted by 67 seeker View Post
Yes I did see that they provide them as per searching the threads. Any issues? Extra parts?

Actually on my '66 manual brake car I didn't use their kit because it wasn't available at the time. Also if I had, I wouldn't have liked the bleeders on the MC they use in that kit, but that's just a personal, visual preference. I'm sure it functions just fine. When I was converting my car I consulted with John Z about bleeders on a MC and his reply in part was, "The '67 "509" master cylinder (with or without bleeders) will work just fine; the bleeders are useless with a horizontal mounting like the manual system uses, which is why the bleeders were deleted on the mid-70's C3 applications."

What I did instead was make up my own kit using CSSB's MC #5455509 with no stamping and no bleeders.
This MC was used on non power brake '74-'76 cars and has the same 1" bore as my single reservoir '66 factory MC so it was compatible with my old push rod.
I also used a front distribution block and front line and rear lines from a '67 and in essence made my own kit.
I've had no issues with CSSB products and recommend them. I'm sure their kit is a quality piece.
My car is not a show car but in the future it could be converted back to a stock '66 system very easily.
My setup works extremely well and I like the safety that a dual reservoir system provides.
I hope that's helpful.

Thomas
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