Why not drill the fire wall for brake booster?

[ianwcox]

Greetings Gurus!
I have spent many hours reading about brake upgrades and am ready to whip in to O'Reilly's and buy a brake booster and dual master cylinder for my drum/drum 65 C10 economy restoration. Sounds like a 1970 C10 booster/master cylinder combo should work for drum/drum with no need for a proportioning valve or metering block. I'll just need to do a little plumbing.

What is the big fascination with not drilling holes in the fire wall? I've read page after page about Cap'n Fab's bracket and extending the linkage, but why? is there a clearance issue that I'm not seeing? This doesn't look nearly as clean to me as a flush mount booster. Plus it costs money (which my wife apparently needs for groceries) and who is actually scared about drilling holes in these trucks? We do it all the time for everything else. What am I missing guys?

Thanks in advance for the sage wisdom

[60-66]

While I do like the Captains bracket and its top of the line quality ! It , to me is so simple and in my opinion , cleaner, to bolt it right to the firewall.The down side to drilling is from a restoration standpoint , leaves 4 drilled holes and some grinding inside the firewall. If you had a super nice low mile survivor type truck I would never do this! Only thing I dont like about the 67 72 boosters is the size and distance from the firewall and clutter with the brake lines. Heres several I did using 1965 1966 Impala brake boosters and these boosters look factory in shape and size.

[Northwest Outlaw]

i'm doing a '76 booster and MC (disc/drum) and am in the same boat about direct firewall mounting. After holding the booster in place and realizing how big it is I saw no way that I could add a bracket and push it farther out into the engine bay. I'll be using one of the original holes and drilling a couple more, but the linkage matches up almost perfectly. I also chopped off part of the bracket that didn't sit well with me visually. I should be mounting in the next few days after it's painted, i'll post more pics on my build thread (linked in my sig)

Keep us posted on your progress

[ianwcox]

Outstanding! Yes, I wish I was starting with a low mile really desirable piece, but that is just not the case.

So, I see the cleanliness of the '65 Impala booster. That's obtainable enough, but that is another single reservoir master cylinder. Did you just play the "Match the Master Cylinder to the Booster" game in the parts store. I think the kids at the counter would get a kick out of that. It's probably just an intermediate shaft issue anyway, right?

[notsolo]

I Think it depends on your skill, comfort level of making parts yourself. My 62 had a hydraulic clutch hole and MC hole. This goes back 25 years so before Al Gore invented the internet. I had a donor 83 front end, rebuilt the disc's brake front cross member, master cylinder and booster. Covered holes in the firewall with aluminum plate. Drilled holes for the booster bracket and made a new rod for the brake booster. There are some challenges getting this all correct and accurate. If your handy give it a shot. In the 2nd photo you may see elongated nut extending the booster rod.

[60-66]

Originally Posted by ianwcox

Outstanding! Yes, I wish I was starting with a low mile really desirable piece, but that is just not the case.

but that is another single reservoir master cylinder. Did you just play the "Match the Master Cylinder to the Booster" game in the parts store. I think the kids at the counter would get a kick out of that. It's probably just an intermediate shaft issue anyway, right?

? It WAS a single reservoir setup originally, yes. The master cylinder I used is the larger Disc brake master for a 1967-1970 Impala . Bolts right up, no difference in shaft function , bolt on and go. For your drum brakes just get a 1967-1970 Impala drum brake master cylinder, bolt on and go. You will need a distribution valve for splitting your lines though.

Edit , I should also ad that I've let several guys and lady's drive my trucks that I've converted, they all loved how easy the trucks stopped. My wife has driven every truck I've owned, manual drums or otherwise, she likes these power brakes or disc brakes the best.

[62chevy302]

Would a 73-87 booster/master cylinder combo work? I would rather do this but I will have to make a brace for the clutch master cylinder no matter what I do

[ianwcox]

Mr. 60-66, you are truly the Sage I was expecting. One last thing: I see the '67 master cylinder for Drum/Drum and it has 2 ports (front and rear.) Why would I need a distribution valve if the lines are already split? Wouldn't I just need a Tee for the front?

[forestb]

I got Captains bracket because I did not like the idea of my firewall not being reinforced where the bracket connects also previously a former friend installed a booster with brackets like the ones posted above and the bolts ran into some of the bracketry on the other side of the fire wall. So be careful and plan out where you drill the holes. Also the rod ended up scraping against the side of the original hole in the fire wall. It was all a big mess in the end but Captains bracket covered that all up.

[60-66]

Originally Posted by forestb

I got Captains bracket because I did not like the idea of my firewall not being reinforced where the bracket connects also previously a former friend installed a booster with brackets like the ones posted above and the bolts ran into some of the bracketry on the other side of the fire wall. So be careful and plan out where you drill the holes. Also the rod ended up scraping against the side of the original hole in the fire wall. It was all a big mess in the end but Captains bracket covered that all up.

Great points to consider forestb. The version in post two though, fit dead center in the hole. I think the installer should be aware of that point when he fits these. A simple template gets it all right on the money. I cant speak for the others posted but the version in post two does not remove or weaken the firewall brace either. Which ever way you go, think safety !

[Captainfab]

In my opinion the two biggest reasons for not drilling holes for just any booster is 1) the chances of the holes coming out on the inside on the edge of one of the formed braces or another not so convenient spot. 2) Using my booster bracket retains the factory mounting locations thus providing a solid and secure connection between the booster/master and the pedal assembly, just as GM designed it.

Personally I can not stand the looks of the '67-'72 booster brackets. The '73-'87 boosters still sit too far from the firewall for my liking. Plus the brackets look entirely out of place unless they are trimmed down. But to each his own. Some people prefer to use the '73-'87 boosters or some other they have acquired for cheap.

[ianwcox]

Last night I ordered this "hot rod" 8" brake booster for a whopping $48 with free freight. I like the zinc finish and the tidy size compared to some of the 11" units. I'm hoping that it will match up with a 67 Impala dual reservoir drum/drum master cylinder that I can get at O'reillys for $27. The picture looks like it has some sort of intermediate shaft and I have high hopes that it will just be plug and play with the M/C.

Drilling the firewall doesn't intimidate me and my particular truck is pretty junky. Plus what I'm going to have to do to the doors to mount speakers makes these holes pale by comparison. My truck will never be on the Concourse at Pebble Beach.

Yes, the boosters with the weird looking built in brackets look horrible. That was a big turn off. My real goal is a clean looking installation and saving money. This budget build is costing waaaaaayyyy too much. I pulled the L6 to put in a gasket set and $3K later its back from the machine shop ready to go. Isn't that how all these builds go though?

[chevy_mike]

So I assume everyone is drilling a 1" lower hole in the brake pedal, so you get the correct pedal ratio. If you hook a power booster to the factory non power brake pedal hole, you will get a low pedal and touchy brakes.

The later factory angled brackets were to angle the push rod down so it would not bind, when mounted 1" lower. They might be ugly but they served a purpose. This is also why I believe the original factory booster had a pivot linkage within the mounting bracket, to allow it to be mounted to the original mounting hole but have the correct pedal ratio. YMMV

[karlbenz]

I used a 84 k10 booster

[Johnny_Lamebridge]

Hi ianwcox,

Here's how I flush-mounted a small CPP booster in my '63.

I made a template out of aluminum to be able to see how big the new opening had to be. Due to the brace on the inside of the firewall, I shifted the opening toward the driver's side of the truck by about 3/16".

I drilled some small holes to see exactly where they were breaking thru. Everything looked good, but the lower holes were partly on a rib on the firewall. I then drilled the holes to size.

To cut away the rib to allow the mounting nuts to sit flat, I used a modified "backwards" 15/16" hole saw. I flipped the hole saw around backwards, stuck it thru the hole from the inside with the hand drill on the outside to cut away the rib at the hole locations.

I hope the pics make sense...

[Johnny_Lamebridge]

Here's what it looks like...

[luvbowties]

Originally Posted by ianwcox

Greetings Gurus!
I have spent many hours reading about brake upgrades and am ready to whip in to O'Reilly's and buy a brake booster and dual master cylinder for my drum/drum 65 C10 economy restoration. Sounds like a 1970 C10 booster/master cylinder combo should work for drum/drum with no need for a proportioning valve or metering block. I'll just need to do a little plumbing.

What is the big fascination with not drilling holes in the fire wall? I've read page after page about Cap'n Fab's bracket and extending the linkage, but why? is there a clearance issue that I'm not seeing? This doesn't look nearly as clean to me as a flush mount booster. Plus it costs money (which my wife apparently needs for groceries) and who is actually scared about drilling holes in these trucks? We do it all the time for everything else. What am I missing guys?

Thanks in advance for the sage wisdom

If you're gonna bypass the bracketry, why not make it an even quicker project by using like a '74-'78 C10 booster and just bolt it directly onto the original 2 studs using the middle pair of holes in the booster's flange? If you just want it to work, this will save time and work fine after you choose the correct m/c to mate with the push rod exiting the front of the booster--gotta get the m/c that has the proper bore in the rear of the m/c piston, to fit m/c properly.

.........NOT the prettiest and neatest installation, though(works great for rat rods!). The brackets seem to be both accurate and neat, and take out all the guesswork!!!
Sam

[luvbowties]

Originally Posted by Johnny_Lamebridge

Here's what it looks like...

Does that system give you sufficient vacuum to stop the truck on a l-o-o-o-n-g stopping scenario?
Sam

[Johnny_Lamebridge]

Originally Posted by luvbowties

Does that system give you sufficient vacuum to stop the truck on a l-o-o-o-n-g stopping scenario?
Sam

As long as the engine's running it does.

Seriously though luvbowties... This was the booster supplied by CPP in their '63 C10 disc brake conversion kit. I just removed the supplied booster mounting bracket.

[luvbowties]

Originally Posted by Johnny_Lamebridge

As long as the engine's running it does.

Seriously though luvbowties... This was the booster supplied by CPP in their '63 C10 disc brake conversion kit. I just removed the supplied booster mounting bracket.

That's great. It's a neat-looking installation and I love the smaller diameter. Sadly some earlier, maybe 1-stagers(?), failed to produce power for a long enough period when applied, esp. with a cammed up engine.
Sam

[Northwest Outlaw]

Here is my '76 booster and MC mocked up after cleaning, trimming the bracket and painting. Currently it's being held by one bolt in an original hole, so i'll have to drill a few more. The top hole on the bracket is one I drilled to get a high location on the bracket to secure it.

[Fatherof3]

I'll add my experience. I used the technique shown here to flush mount a power booster with a dual master cylinder on a 65 C20 with stock drum brakes. I drilled additional holes in the pedal at 1" and 1 1/2" below the stock hole. I started with 1" bore dual master cylinder that was for a manual disc brake square body C10 and mounted it on a 8" dual diaphragm booster. Thinking I didn't need a 1 1/8 master when I still had the stock front drums that had been run by a 1" single master cylinder stock. With the booster mounted flush to the firewall I didn't have the benefit of the booster being angled up for better push rod geometry and was limited to using the 1" lower hole as the 1 1/2" lower hole in the pedal arm would not work without binding. I adjusted the brakes but did not add a 10lb residual valve to start with and could not get the brakes to engage. I tried a 1 1/8" master cylinder for a power disc brake square body C10 and with this I got the brakes to engage with a lot of pedal travel and they were very grabby and hard to control. I was at the go big or go home point so I bought a 1 5/16" bore master cylinder for a 1980 C30. With this I had plenty of stopping power that was easy to control but still more pedal travel than I wanted. After adding a 10lb residual valve to the fronts I now have stopping power and pedal travel I am very happy with.

Side notes:I used master cylinders intended for front disc brakes hopping that I will change to front discs soon.

I don't plane to add a residual valve to the rear as it may increase the tendency of the rears to lock up early.

The 1" bore master cylinder was designed to have the front brakes plumbed to the rear master cylinder reservoir, the 1 1/8" master cylinder was designed to have the front brakes plumbed to the front reservoir, and the 1 5/16" bore master cylinder is designed to have the front brakes plumbed to the rear reservoir.

Not saying anybody should do what I did, just sharing.

[rvrfoot]

Just drill it.

[The Rocknrod]

Here are pics of the brake pedal assembly (off the truck) with the booster installed.
Capn Fabs bracket doesnt change the factory mounting holes and as you see the factory uses the bracket inside the truck for strength.

[joe dirt]

Originally Posted by The Rocknrod

Here are pics of the brake pedal assembly (off the truck) with the booster installed.
Capn Fabs bracket doesnt change the factory mounting holes and as you see the factory uses the bracket inside the truck for strength.

thanks for the visual, this make much more sense now