Flush Mounting My Power Brake Booster

[KyleSeal]

I could not find any threads on this topic that had any more detail than just a brief paragraph, so I figure I'd pit my experience out there.

I started by determining how much to widen the old master cylinder hole on the firewall, I opened it to about 2 1/8 inch, instead of grinding with a die grinder or carbide bit, I got a Milwuakee hole saw. I took some 1/8 inch flat bar, and made a bracket so I could center the hole saw and hold it steady when drilling.

From there I made a template out of scrap wood, transferred the markings onto the firewall and drilled accordingly.

You can see as well I had to modify the column bracket, I took one of my extras and chopped it up to clock the other bolt hole in a new location, keeping a factory style appearance, and maintaining rigidity for the column.

Going inside the cab, I had to remove a lot of the bracing in this area for the booster mounting holes/flange. I want the firewall to be as strong as before, so I took some of that 1/8 flat bar and welded it into the old brace location, and as you can see I seam sealed and painted it.

Now it is fully flush mounted. The only thing I do not have in here is to drill the old brake pedal assembly bracket, but thats a given. I will more than likely take the old studs to the bracket pedal bracket and reverse them to fill those holes. To accomplish this I may have someone machine me a 1/8 plate to sandwich between booster and firewall, much like the hydroboost setups do.

Once I get to the pushrod setup, I will report back.

[KyleSeal]

Inside pix and final assembly pix.

[dmjlambert]

That came out nice. Did you do this to make it look neater, or are there some functional benefits as well?

[hugger6933]

Nice job, I have a 67 parts truck somebody did a similar thing to but yours is neater. Jim

[KyleSeal]

Originally Posted by dmjlambert

That came out nice. Did you do this to make it look neater, or are there some functional benefits as well?

I like the neatness of it, I doubt theres much more benefit to it other than less linkage to wear out. Saw it on Nacho truck from Delmo and wanted to go for it.

[RichardJ]

I did the same but used a booster from a Chevy Van. It's larger in diameter, but not as deep. I don't think I had to cut the hole larger, but it has been almost 20 years.
The reason i did it, was to get the MC back away from the carb and aftermarket manifold on the inline 292.

[KyleSeal]

Here's my closer, the pedal pushrod(s);

So after much thought, I decided to utilize the bellcrank assembly on the inside of the cab. I did this by using just the actual pivoting bar the pushrods will attach to, and drilling a hole on the brake assembly, and welding on a 'leg' to the other side, to slide the pin through and hold the pivot bar in place.

When adding the pivot bar where I did, I had to cut the brake pedal assembly to create a relief for the arms to swing full motion at the top, so I took 1/8" flat steel I had and bent a radius into it to reinforce this area. This does not interfere with the return spring when being careful and trimming where needed.

Could I have just used the lower hole for the 4:1 ratio, sure, but I didnt like the angle it produced. This will be cleaner, operate better and have longevity.

I attached the diagram I used to calculate this, as per Wilwoods site: https://shop.wilwood.com/blogs/news/...o%20of%209%3A1.

[KyleSeal]

Just realized I forgot to add a photo of how I split the column bracket to clearance the booster. Here it is;

[Jason Banks]

Glad you came back to post the pic, I missed this thread the first time. Nice work.

[LNP]

You couldnt have just used a adjustable rod from the pedal to the booster? Hard to tell in the photos if the geometry is wrong for that.
You did some great craftsmanship doing this.

[KyleSeal]

Originally Posted by LNP

You couldnt have just used a adjustable rod from the pedal to the booster? Hard to tell in the photos if the geometry is wrong for that.
You did some great craftsmanship doing this.

Thank you. To the best of my knowledge, the linkage is proper. Its achieving two things: ratio and angle. With an adjustable clevis, the angle would be extreme trying to use the correct ratio. This bracket essentially just moves the input upward and corrected.

[KyleSeal]

Originally Posted by Jason Banks

Glad you came back to post the pic, I missed this thread the first time. Nice work.

Thank you!

[LNP]

Originally Posted by KyleSeal

Thank you. To the best of my knowledge, the linkage is proper. Its achieving two things: ratio and angle. With an adjustable clevis, the angle would be extreme trying to use the correct ratio. This bracket essentially just moves the input upward and corrected.

I wasn't meaning what you did was improper in any way. It just looks to me that it could have connected directly without the piviot so I thought I would asked.