power brake linkage help

[j_cst_10]

I picked up a rebuilt powerbooster and new master for my '70 to convert from manual brakes to power brakes.

The power booster has a "bell crank" linkage set up. I've looked through old posts and have seen people put the linkage together from original set ups, but is there anywhere I could buy all the parts new?

Since the truck is manual brakes, I have the part that connects to the brake pedal but the rod is obviously not correct.

Do I need to put a WTB up or can I piece it together with new parts? I did some google searching and LMC browsing but can't find anything definitive.

[RodnRudy]

Classic Performance Products sells the complete power brake assembly.MC, Booster, and Linkage.

[j_cst_10]

Originally Posted by RodnRudy

Classic Performance Products sells the complete power brake assembly.MC, Booster, and Linkage.

Yes thank you. Trying to use my current set up which is just missing the linkage from the pedal to the booster

[ratty69]

Can't help you with a source for one new or used, but here are the measurements from one removed from a 72 C20:

length: 9.25" center to center of holes

rod diameter: 7/16"

hole diameter, pedal end: 9/16" (bolt is special shouldered type)

The rod length is adjustable at the pedal end.

I tried to attach a pic of the parts you'd need to make one, but I can't add pics from my computer anymore? It requires a link to a web site to add pics now?

[Jason Banks]

There are some universal kits you could use. Like - https://www.amazon.com/dp/B09TDD4M2Q/

The are not as good as the stock parts. You are better off if you can find a stock one. I'd post at WTB in the parts board...

[j_cst_10]

Originally Posted by ratty69

Can't help you with a source for one new or used, but here are the measurements from one removed from a 72 C20:

length: 9.25" center to center of holes

rod diameter: 7/16"

hole diameter, pedal end: 9/16" (bolt is special shouldered type)

The rod length is adjustable at the pedal end.

I tried to attach a pic of the parts you'd need to make one, but I can't add pics from my computer anymore? It requires a link to a web site to add pics now?

Thank you this is really helpful. I assume this is off of the same “bell crank” linkage set up?

I can use my pedal end that is on my manual set up and hopefully come up with the rest. They do sell some universal pieces that might work knowing the dimensions you gave me.

[Rust_never_sleeps]

I agree that the OEM parts are beefier and have the double threads so you can turn the middle piece like a turnbuckle.

Some folks beef up the aftermarket rods by screwing more coupling nuts on.

In case it wasn't mentioned(my kit said nothing), you'll want the rod at a different position on the pedal lever for Power vs manual as well.

[j_cst_10]

Originally Posted by Rust_never_sleeps

I agree that the OEM parts are beefier and have the double threads so you can turn the middle piece like a turnbuckle.

Some folks beef up the aftermarket rods by screwing more coupling nuts on.

In case it wasn't mentioned(my kit said nothing), you'll want the rod at a different position on the pedal lever for PS vs manual as well.

I completely forgot about the different position on the pedal. Thanks for reminding me. That would have caused some headaches.

[Rust_never_sleeps]

power brakes, NOT PS ;-)

[j_cst_10]

Perhaps this will thread onto the rod end I already have for my manual brakes?? Not sure on overall length or if it’s fine thread or not. Have to do some investigating tomorrow.


https://www.ebay.com/itm/27449512184...emis&media=SMS

[ratty69]

I tried to attach a screenshot of that, but it wouldn't let me. I guess I should have just linked it.

Yes, the measurements were from a bellcrank setup.

My pedal only had one hole in it, I had to drill one 1" lower when I upgraded to Captain Fab's bracket. I always understood that the point of the bellcrank was to correct the geometry for power brakes using the same mounting hole as manual. Maybe I'm wrong? Not the first time...

Forgot to add, I hope you also got the support brace that goes from the booster to the firewall. That whole contraption is heavy!

[Classic Bowties]

Originally Posted by j_cst_10

I picked up a rebuilt powerbooster and new master for my '70 to convert from manual brakes to power brakes.

The power booster has a "bell crank" linkage set up. I've looked through old posts and have seen people put the linkage together from original set ups, but is there anywhere I could buy all the parts new?

If set on chasing all new aftermarket pieces, proceed with caution and do your research as there are some poor quality power brake conversion parts out there. Here are a few pics to help your thread along and if interested in using better quality OE parts, we can offer you the below pictured OE used power booster to firewall mounting bracket and push rod setup. Let us know, Mel


***10/04/23*** j_cst_10 has passed, these brake conversion parts have now been listed/offered in the below linked parts board f/s thread.


http://67-72chevytrucks.com/vboard/s...43#post9247843

.

[LNP]

Originally Posted by j_cst_10

Yes thank you. Trying to use my current set up which is just missing the linkage from the pedal to the booster

These guys sell brand new ones complete

https://www.speedwaymotors.com/Power...iABEgJdvvD_BwE

https://www.summitracing.com/parts/s...yABEgKUwfD_BwE

[Rust_never_sleeps]

Originally Posted by ratty69

I had to drill one 1" lower when I upgraded to Captain Fab's bracket. I always understood that the point of the bellcrank was to correct the geometry for power brakes using the same mounting hole as manual.

I had assumed the same thing, seemed like an easy thing to correct the leverage in that linkage, but apparently not

[Classic Bowties]

Originally Posted by j_cst_10

Have to do some investigating tomorrow.

Per your pm, here are some pictures of the OE used lower steering column to gear box intermediate shaft and p/s rag joint coupler setup that we have available/ready to ship, can combine ship everything together if interested. Mel
.

[Classic Bowties]

j_cst_10 has passed. For anyone else needing/looking, the above pictured lower steering column to gear box intermediate shaft and p/s rag joint coupler setup has now been listed/offered in the below linked parts board f/s thread. Mel


http://67-72chevytrucks.com/vboard/s...43#post9247843

.

[Rust_never_sleeps]

Originally Posted by Classic Bowties

[B] j_cst_10 has passed

Rest in Peace ;-)

[j_cst_10]

If only! I ordered the eBay link I shared above mainly out of curiosity. I’ll update everyone with pictures and measurements.

My thinking is I can use it with the pedal end from manual linkage set up. To be determined.

[Rust_never_sleeps]

I was wrong about the bell crank, Ratty69 was correct.

here's the link with the complete method to sanity check your final ratio
https://shop.wilwood.com/blogs/news/...-crank-systems

[j_cst_10]

I’ll update this thread when I get the booster installed. My eBay part that I have a link to, seems to be correct when used with the pedal end from the manual set up.

Length measurement is 9-9 1/4 with the pedal side attached and fits the bell crank end.