# R&R '65 GTO Manual Brake Master Cylinder



## wishihaditback (Jun 9, 2011)

Hello all. Looking for advice/tricks for what I thought would be a straight forward master cylinder replacement. I just read an old old thread on the forum where the replies were just disconnect line from m/c and remove the two nuts holding the m/c to the firewall. What wasn't mentioned was the connection from the m/c rod to the brake pedal assembly. Having a clutch I have no room to do anything from that side. How do I disconnect the rod? And once that is accomplished, what's the adjustment method for the new m/c? It is a single reservoir for manual brakes. Thanks.


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## Old Man Taylor (May 9, 2011)

The rod stays in the car. What you read before is accurate.


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## wishihaditback (Jun 9, 2011)

Ok. I unbolted the m/c at the time but the rod doesn't seem to want to come out of the m/c. Does it "pop" out? As you can see from the new m/c photos, the rod is connected and held in by a c-clip set up. If the old one has the same set up, it would seem the only way to disconnect it would be from the pedal side. As you can tell, this would be my first m/c replacement.


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## PontiacJim (Dec 29, 2012)

Not sure if the cylinder is correct or not. I googled 1965 MC and go several hits. I found a 1964-65 like yours with the rod attached.

I found others, which is what is being noted in the previous posts, without the rod. 









1955-66 GM Master Cylinder for Drum Brakes, Stainless Sleeve


Brake fluid can ruin your master cylinder in just a few years. Stop the problem by using a stainless steel sleeved master cylinder. This is an OEM-style single reservoir master cylinder for many 1955-1966 Chevy applications with drum brakes. Will not work with disc brakes. Features a 1" bore and...




www.speedwaymotors.com





The Speedway type is what most of us are familiar with. No rod attached. The push rod remains attached to the brake pedal. You simply pull the MC and reinstall back onto the push rod and you are good to go.

A Service Manual would most likely show this in their brake systems section. Different braking set-ups were sometimes used depending on assembly plant and supplier. If you have a matching set-up, ie it will not pull out because the rod is attached, then yes, you probably have to undo the push rod from the brake pedal. It should not be too difficult. It may have a clevis pin/clip arrangement.

When you pull the rod off the pedal, there may be 2 holes on the swing arm. One is for manual MC and the other is for power MC. Just note which hole - upper/lower - that you remove it from to put it back in the correct hole.

Once you get the push rod off and pull the MC, then I would measure the length of the threaded rod/nut and transfer that over to the new MC push rod. Then you should be good to go from there and reinstall.


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## wishihaditback (Jun 9, 2011)

Thanks for your replies and suggestions. The next pics show the old crusty m/c, but must be of the same type as the new one as it cannot be pulled out so it must have the c-clip set up. I like the Speedway type as it has what I think is the original color cap, but I gotta keep the new one. So I'm back to square one I guess and will be hanging upside down like a bat under the dash in 95 degree heat trying to figure out the pin/clip thang. Thanks for all the input!


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## PontiacJim (Dec 29, 2012)

wishihaditback said:


> Thanks for your replies and suggestions. The next pics show the old crusty m/c, but must be of the same type as the new one as it cannot be pulled out so it must have the c-clip set up. I like the Speedway type as it has what I think is the original color cap, but I gotta keep the new one. So I'm back to square one I guess and will be hanging upside down like a bat under the dash in 95 degree heat trying to figure out the pin/clip thang. Thanks for all the input!


Don't make it sound so bad. Give the wife $50.00 and send her off to the mall to go shopping. Then you pay one of those Hooter girls to deliver a soft drink and burger (Corona virus thing because restaurants are mostly closed) and have her to hang around and wipe the sweat off your brow as you are upside down under the car looking straight up at her...........

Just gotta know how to turn an uncomfortable situation into an enjoyable one. Who knows, you may have to explain to the wife why all of a sudden each weekend you are working on the MC and giving her money she never asked for and sending her shopping each weekend.


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## Mine'sa66 (Oct 30, 2019)

Some have the rod fixed to the master and you'll have to unclip the arm from the pedal. I just did a master swap on my 66. The old had the floating rod, the new had a fixed rod. I have a clutch pedal too (auto, but clutch pedal still there). So at first I tried to thread the master and the rod together with the rod attached to the pedal. Nope, after 3 cross threads, I fought the clip off the brake pedal. Take a few deep breaths, get your patience up and dive under that dash


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## wishihaditback (Jun 9, 2011)

All good ideas! Just got off the phone with Hooters and apparently I'm just outside their delivery area. Thanks again guys.


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## O52 (Jan 27, 2019)

Might be easier to pull the drivers seat out to give you some room


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## wishihaditback (Jun 9, 2011)

Thanks 052. Will most likely do that.


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## wishihaditback (Jun 9, 2011)

Update. Took the drivers seat out, laid a old quilt on the floor, eased my way in upside down, and with a bright light and my reading glasses, disconnected the m/c rod from the pedal bracket and removed the m/c. Was going to install the new one right then and there but saw the clutch rod boot was dry rotted and got one on order. Figured it was easier to deal with that while the m/c was out. Since I'm here, I'm replacing all the brake lines and have my pre-bent replacements....do I paint them black?.....or were they unpainted from the factory? And lastly, I'm considering converting from manual to power brakes and locating the various parts. What I'm not clear on is what bracket(s) are needed for the pump? I've seen the upper one that the pump rotates on, but is there a lower one? Anywho, thanks guys for the responses to my original m/c question!


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## Mine'sa66 (Oct 30, 2019)

wishihaditback said:


> Update. Took the drivers seat out, laid a old quilt on the floor, eased my way in upside down, and with a bright light and my reading glasses, disconnected the m/c rod from the pedal bracket and removed the m/c. Was going to install the new one right then and there but saw the clutch rod boot was dry rotted and got one on order. Figured it was easier to deal with that while the m/c was out. Since I'm here, I'm replacing all the brake lines and have my pre-bent replacements....do I paint them black?.....or were they unpainted from the factory? And lastly, I'm considering converting from manual to power brakes and locating the various parts. What I'm not clear on is what bracket(s) are needed for the pump? I've seen the upper one that the pump rotates on, but is there a lower one? Anywho, thanks guys for the responses to my original m/c question!


What pump are you referring to? Are you thinking of adding a hydroboost system?


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## wishihaditback (Jun 9, 2011)

Just the regular stock type power steering pump.


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## Mine'sa66 (Oct 30, 2019)

wishihaditback said:


> Just the regular stock type power steering pump.


Got it, you said changing from manual to power _brakes_, that threw me off. Power steering=Good


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## wishihaditback (Jun 9, 2011)

Oops....my bad! Yeah, I meant power steering. Talking about the master cylinder I had brakes on the mind! Thanks for the heads up.


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