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Old 06-12-2023, 11:28 PM   #1
K10-Kansas
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remove rod from brake booster

Hi all. Thanks in advance if you can help me with this. While bleeding the brakes my brake pushrod bent clear to a 45 degree angle where it screws into the clevis. I think it wasn't threaded deep enough.

Doesn't the pushrod pop straight out of the back of the booster to remove it? I gave it a few hard pulls and couldn't get it.

Second, isn't it kind of ridiculous that this thing bent so easily? My wife was pushing the pedal while I was bleeding the brakes and wow, I really think these things should be stronger.

And thirdly, can I put in any old pushrod so long and it screws into my stock clevis? Like maybe this universal one?
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Old 06-13-2023, 07:04 AM   #2
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Re: remove rod from brake booster

I found this answer from 2004 that may be the ticket on the pushrod. Can anyone confirm this? http://67-72chevytrucks.com/vboard/s...09&postcount=2

In the post, Americanrider says "...On the booster end there is a small spring clamp that also has a thrust washer. Best way to get that off is a long-nosed set of pliers, bend the edge of the spring clamp away and push. ..."
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Old 06-14-2023, 03:04 AM   #3
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Re: remove rod from brake booster

I watched a video a few hours ago (with an MBM booster?) and they just pulled the MC pin out with pliers

I've read how some people "fortify" the pedal rod with additional threaded sleeves so it can't bend.
TBH, not bending is something I assumed was an intrinsic requirement for said part :shrug:
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Old 06-14-2023, 06:29 AM   #4
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Re: remove rod from brake booster

Quote:
Originally Posted by Rust_never_sleeps View Post
I watched a video a few hours ago (with an MBM booster?) and they just pulled the MC pin out with pliers

I've read how some people "fortify" the pedal rod with additional threaded sleeves so it can't bend.
TBH, not bending is something I assumed was an intrinsic requirement for said part :shrug:
That's a great idea. I'll set it to the right length and then for any exposed threading I'll put a threaded sleeve on it. For any exposed threading I'll put a sleeve on it.

I read on another forum that you have to take the booster apart to remove the rod. On another forum they said to use needle nose pliers to remove a pin in the booster along the rod. I saw on a video with a hydro boost (not a vacuum boost) where the guy put the boost in a vice and knocked the rod out with a hammer.

The C10 truck show I entered is this Saturday so I'm just going to drive over to classicpartsamerica and get a booster with the brake rod, brake clevis, and mounting brackets all in one unit. That way I'm not trying to match up 3 different pieces on my frankentruck.
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Old 06-14-2023, 06:41 AM   #5
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Re: remove rod from brake booster

I figured out why my rod bent.

Other than being weak metal, before I got the truck it had been set up so that the brake pedal pushed the brake rod directly into the booster. From the factory it looks like the brake rod is supposed to push a pendulum and the pendulum pushes into the booster. The way mine was set up, the brake pedal would have pushed into the booster at a bad angle because my booster bracket doesn't have the pendulum. When I went online looking for a new mounting bracket last night, I saw that all the brackets looked like this one below in this picture.
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Old 06-14-2023, 01:56 PM   #6
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Re: remove rod from brake booster

The (older?) ones that don't have the lever tell you to drill a new hole in the pedal arm and move it down an inch, which reduces the leverage and changes the angle slightly.
PO might have tried to set travel to something "interesting"
IIRC, factory would have been set up straight-ish to the bore(angle has to change some during travel no matter what)
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Old 06-14-2023, 02:22 PM   #7
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Re: remove rod from brake booster

Looks like I misunderstood which rod you were pulling out, my bad :facepalm:
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Old 06-14-2023, 06:23 PM   #8
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Re: remove rod from brake booster

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Looks like I misunderstood which rod you were pulling out, my bad :facepalm:
Well my thread is definitely all over the place trying to figure out my brake issues.
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Old 06-14-2023, 07:46 PM   #9
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Re: remove rod from brake booster

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Well my thread is definitely all over the place trying to figure out my brake issues.
I get to climb back under the dash to adjust that linkage tonight. I'll prolly pull the seat and the steering wheel before I try that contortion act again.
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Old 06-14-2023, 10:55 PM   #10
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Re: remove rod from brake booster

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I get to climb back under the dash to adjust that linkage tonight. I'll prolly pull the seat and the steering wheel before I try that contortion act again.
Is the adjustment you're going to do, spinning the clevis to lengthen or shorten the pushrod? If so, is the only outcome the pedal sitting closer or further from the floor? Is there another outcome?
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Old 06-16-2023, 12:06 AM   #11
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Re: remove rod from brake booster

Quote:
Originally Posted by K10-Kansas View Post
Is the adjustment you're going to do, spinning the clevis to lengthen or shorten the pushrod? If so, is the only outcome the pedal sitting closer or further from the floor? Is there another outcome?
I need to take out the play first, and make sure the rod is rigid so I can finish bleeding.
Then I'll see where the pedal sits, and whether I can get the position where I want it.
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Old 06-16-2023, 07:33 AM   #12
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Re: remove rod from brake booster

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Originally Posted by Rust_never_sleeps View Post
I need to take out the play first, and make sure the rod is rigid so I can finish bleeding.
Then I'll see where the pedal sits, and whether I can get the position where I want it.
If someone adjusted their pedal too close to the ground I imagine they might not be able to apply much pressure to the back brakes right? If the pedal is too far from the floorboard I imagine they would then reach the end of useful travel while still several inches away from the end of possible travel because they would run into the very tense spring in the master cylinder that comes into play at the end of the small reservoir use/rear braking portion right?

I'm trying to figure out how high to adjust my pedal so that it is low but that I still get the full use of the rear brakes. Is the only way to do this, twisting the clevis and then pushing to the floor and repeating that until you feel that very resistant spring in the master cylinder at the end of the rear braking travel?

It seams that that would be the process but this is my first time doing this so I was unsure what the pros do.
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Old 06-17-2023, 06:21 PM   #13
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Re: remove rod from brake booster

it's all new to me too. I know I need to take the play and flex out of the linkage and I need enough travel to bottom the MC without hitting the firewall with my fat panicked @ss hammering that pedal down. Once I get that and I'm sure the lines are bled, I'll prolly drive it for a while and see if the pedal height bothers me, then I'll adjust that.

This I think is the video that shows more about how to fiddle with these things than the rest: https://www.youtube.com/watch?v=EGanbFC-8v8&t=243s
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Old 06-20-2023, 01:03 PM   #14
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Re: remove rod from brake booster

I managed to pressure bleed the backs where vac bleeding repeatedly failed(yes the shuttle valve is pinned), so now I'm actually able to feel a hard pedal, so I know the linkage isn't flexing or running into limits of travel.
Going to go in and recheck everything is safe, then I'm going to sleeve that rod (for add'l rigidity). Pedal height seems OK for me as is, but once I start actually driving the beast again I may revise that opinion
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