Author Topic: Pulling the single circuit master cylinder from a 1967 Fastback  (Read 107 times)

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Offline kinggeorge13

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Pulling the single circuit master cylinder from a 1967 Fastback
« on: November 24, 2018, 06:24:19 PM »
Removing my single circuit master cylinder out of my 1967 Fastback. Definitely a single circuit booster even though I've read and seen lots of photos of a dual circuit booster in 1967 Fastbacks but I think possibly there was a design change mid-year and the earlier ones had the same single circuit one I have or someone replaced it sometime during it's life with an older one they had laying around. But there is only one line coming down from the reservoir so it seems original.

Anyways, I've removed the input line from the reservoir and the three output brake lines and the two bolts that hold it in place. It came nice and loose but when I go to pull it off, as I pull it harder I can feel my pulling is actually pulling down the brake pedal a little inside. From stuff I've read and watched, it seems like I should be able to just pull the master cylinder right off the pushrod tube (and then push it back on when I'm reassembling it) but I worry I'm missing some little important detail about this particular vintage of master cylinder that was not designed to just pull out? I don't want to give it a good hard pull until I know that it is supposed to just come out.

The attached two photos is the depiction of what I believe I have in my Fastback.
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Offline kinggeorge13

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Re: Pulling the single circuit master cylinder from a 1967 Fastback
« Reply #1 on: November 24, 2018, 06:40:26 PM »
The following are photos of the master cylinder under the car and a photo of the end of the rubber boot on the master cylinder from behind the brake pedal.
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Offline BUSDADDY

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Re: Pulling the single circuit master cylinder from a 1967 Fastback
« Reply #2 on: November 24, 2018, 07:31:45 PM »
If you are changing it and you F it up by pulling does it really matter?, I guess removing the clevis pin on the pedal first wouldn't hurt, you can deal with it on the bench then.
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Offline kinggeorge13

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Re: Pulling the single circuit master cylinder from a 1967 Fastback
« Reply #3 on: November 25, 2018, 06:30:33 AM »
I'm hoping to save and reuse the master cylinder back into the car.   I guess the information on why I'm removing it would have been useful.  The rubber "plug" at the top of the master cylinder where the line from the reservoir is attached was rotted out and began leaking brake fluid profusely.   Based on it's location under the undercarriage of the hood area and the rubber plug being on top, there is little room up their for hands and no room for tools to get at and remove the old plug easily and mine was coming apart.   Regardless of the best care I could employ, it broke in half leaving the bottom half inside the master cylinder.  So now it's got to come out so I can remove the rest of the plug without tearing it to pieces (hopefully) and then more easily install the new replacement plug. 

But yeah, the more I read the more it really seems that it should  just  pull out.   Getting at the clevis and dealing with the brake pedal spring was apparently designed for someone younger (flexible) and smaller than me.   So later today I'm going to give that master cylinder a mighty pull.  Hopefully it comes out and REALLY hoping I don't find that the rubber plug has a bunch of disintegrated rubber down inside the master cylinder. 
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Offline kinggeorge13

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Re: Pulling the single circuit master cylinder from a 1967 Fastback
« Reply #4 on: November 26, 2018, 07:08:47 AM »
And....yep, with a minor more amount of determined pulling, the master cylinder popped off of the pushrod tube.  Once on the bench I was able to remove the rest of the input line plug which had indeed rotted pretty much in half.   Cleaned out the connector area where the plug goes in.    The rubber boot on the end of the master cylinder where the pushrod goes into has some wear/damage/tearing that's not too bad but certainly not as secure/protecting as it should be so I'll order a replacement boot and once it's arrived, I'll put it all back together with the new boot and the new input line plug, reinstall it and reconnect all the lines.  Then it's time to start soaking the bleeder valves on each wheel with penetrating oil (Sea Foam) for a couple days to help ensure I don't risk breaking any off while bleeding the brakes (never a good day when that happens).   
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Offline Bruce

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Re: Pulling the single circuit master cylinder from a 1967 Fastback
« Reply #5 on: November 28, 2018, 11:59:06 PM »
At this point it would be advisable to take the whole MC apart and clean out the gunk.

Offline kinggeorge13

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Re: Pulling the single circuit master cylinder from a 1967 Fastback
« Reply #6 on: December 01, 2018, 07:42:42 AM »
Yeah, I was wondering and worrying about that.   Putting it all back together and going through the whole process only to find my brakes are not working great because crap (or rubber bits) inside the master cylinder are blocking small passages would make me sad.   The rubber boot I received (yesterday) from CIP1 came with a bunch of rubber washers and a few parts so I'm assuming that's the replacement parts for inside (I missed that it all came together when I ordered the boot....I guess someone is trying to tell me something).   I will tackle that this coming week.

What's funny/crazy about all this?   The Fastback was on the road and having a blast when we then parked it inside the garage for the winter about 6 - 8 weeks ago.   Since then while it was just sitting there doing nothing, the main rubber 6" fuel hose from the gas tank to the main pipe started leaking like crazy (old rubber line, completely disintegrated) and all over my garage floor when we finally noticed it.  Fixed that with nice new hose and a week later the master cylinder rubber plug for the inlet line started to leak slowly but steadily making a new darker stain within the gas stain on my garage floor.   Now I'm into likely rebuilding the master cylinder. 

On the other hand, this time last year I didn't have a garage and was outside working under a giant tarp freezing my butt off.   I guess I should not complain.   

And yeah, should have known to replace that fuel hose already but when we bought the fastback, the lines had been already been replaced in the engine area so I dumbly assumed they'd all been done.  Yep..........except that minor one coming right out of the gas tank.   

Live and learn.

-George
Learning from my mistakes I'm clearly going to be a genius one day!

 

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