Differences in brake booster brackets/linkages…

[AllGoNoShow]

I have a 68 which previous owner converted to front power disc brakes. Not sure who the manufacturer is but it has what appears to be a 8” dual diaphragm booster which has the brackets and swivel type linkage outside of the firewall as seen below. This puts the MC pretty far out from the firewall and the whole thing leans forward and doesn’t sit close to level for some reason (see below).

I’ve also seen some people put the booster closer to the firewall with Captain Fab’s brackets which seemingly puts the booster lined up with the hole in the firewall so no swivel linkage is needed.

What are the pros/cons of each? The only reason I see for the larger bracket with swivel linkage is that it moves the booster up so there is more room? Trying to evaluate my brakes and understand all the differences as I’m looking to replace the MC and proportioning valve. Thanks!
Posted via Mobile Device

[RustyPile]

You appear to have the very common booster/MC conversion setup sold by Summit.. The "swivel linkage" as you call it if actually reduces the pedal travel needed to move the MC piston. Here is a link to the setup sold by Summit.. BTW, I've had this unit in my truck for ~ 4 years and it has been trouble free..
https://www.summitracing.com/parts/sum-760197

[A1971Blazer]

I bought this one from a fellow board member and installed it on my K/5 Blazer.
https://67-72chevytrucks.com/vboard/...hlight=booster
I'm not sure why they all tilt downward but I shimmed under the bottom bolts and leveled it.
The difference in braking is like day and night compared to the old factory one.
It easily locks all 4 wheels.

[kev2809]

i ordered an 8" one for a c10 off ebay and it looks exactly like yours, and mine sits exactly the same. i dont like it, and also i feel like because its leaning, brake fluid comes out the front when the brakes are applied. i dont know if maybe the lid isnt exactly squeezed tight, because it does seem like it could be more snug. the seller said i could try shimming the bottom of the bracket to the firewall. but it does stick out a lot more than the one that i had on the truck before

[67 twins]

Originally Posted by kev2809

i ordered an 8" one for a c10 off ebay and it looks exactly like yours, and mine sits exactly the same. i dont like it, and also i feel like because its leaning, brake fluid comes out the front when the brakes are applied. i dont know if maybe the lid isnt exactly squeezed tight, because it does seem like it could be more snug. the seller said i could try shimming the bottom of the bracket to the firewall. but it does stick out a lot more than the one that i had on the truck before

Well the master cylinder lid should be air tight. So if you are loosing fluid from the lid then it's not sealing properly.

[kev2809]

ya I think I have a lid issue as well then.

does the push rod need adjusting again if the bottom bracket is shimmed?

OP, if your brake lines reach fine I would leave it alone. I don't know why they sit so far out though, and angle down. but it seems most aftermarket ones do

[A1971Blazer]

Originally Posted by kev2809

ya I think I have a lid issue as well then.

does the push rod need adjusting again if the bottom bracket is shimmed?

The push rod might need a slight adjustment if you shim the bottom of the bracket after you have already installed and adjusted it.
I did a full install, so I attached the rod to the pedal after I mounted the booster.
It works flawlessly.

[69cam]

Sorry to hijack this thread. Thank you A1971 blazer for posting a pick of this setup. I have been thinking about purchasing one. Is yours the cast iron version and can you confirm that it does not have CPP cast into it? Thanks for any help.

[68 C10 Driver]

AllGoNoShow, mine is very similar to yours but my booster is the larger size. I do not think mine tilts quite as much, but here is how it looks. I am still into my build, so I do not have fluid in it yet.

[68 C10 Driver]

Here is a good side view, I guess the tilt is a bit more than I thought, but it isn't crazy...

[A1971Blazer]

Originally Posted by 69cam

Sorry to hijack this thread. Thank you A1971 blazer for posting a pick of this setup. I have been thinking about purchasing one. Is yours the cast iron version and can you confirm that it does not have CPP cast into it? Thanks for any help.

the master cylinder is cast iron, I cleaned it with laquer thinner and painted it. I hate seeing a rusty master cylinder.....
and no, there is no lettering or anything on the master cylinder, it came with the proportioning valve and the lines to connect it to the MC...

[69cam]

Thank you for the reply. That's good to know. I plan to order one soon. Thanks again.

[AllGoNoShow]

So besides the first reply mentioning that this type of linkage allows for less pedal travel to move the MC, is there any other advantage to this bracket then the ones that keeps the booster closer to the firewall with the connection/linkage being entirely inside the cab? It seems unnecessarily complicated if that is the only reason.

[ghackett1]

Originally Posted by 68 C10 Driver

Here is a good side view, I guess the tilt is a bit more than I thought, but it isn't crazy...

I like the look of that set up, where did you get it?