11" single diaphragm booster or 8" double?

[68isgreat]

On my 68 K10 with front disc conversion, I have a single diaphragm 11" booster and proportioning valve:



It works pretty well, but with the larger tires on a 4x4, I'm wondering if I would see an increase in stopping power with a dual diaphragm 8 or 9" booster?

[Steeveedee]

If you're finding that much decrease in braking performance, you might consider larger rotors. I don't know if bigger tires contribute that much, but they certainly have a larger moment of inertia than stock. What vacuum does your engine pull?

[68isgreat]

Originally Posted by Steeveedee

If you're finding that much decrease in braking performance, you might consider larger rotors. I don't know if bigger tires contribute that much, but they certainly have a larger moment of inertia than stock. What vacuum does your engine pull?

Vacuum is 20. Rotors are stock square body rotors.

[NCDEERE]

Hydra boost.

[68isgreat]

Originally Posted by NCDEERE

Hydra boost.

Really? I don't know anything about that. Ill look into it.

[PbFut]

I like my hydoboost. Be sure to add a cooler in the return line if you decide to go that route. I added one recently after finding the fluid looked dark too fast. There is a noticable improvement with consistency in feel on hot days with the cooler.

[57taskforce]

My K20 has a 5” lift and 35’s. I run hydraboost and it stops very well. It’s got a square body front dana 60 and rear 14 bolt with 13” drum brakes, for now; I have a factory rear disk axle built for it that I haven’t gotten a round to installing yet.

With the 1 ton square body brakes and the hydraboost i can lock the 35’s up if i want to too. I used the brackets for hydraulic clutch and hydraboost from captain fab here on the board. The hydraboost is from an 08 silverado and the master is the Napa replacement for a ‘72 K20. Power steering and Hydraboost lines are mostly Napa replacement square body stuff. I used the oe steering pump with a full flow return T to tie the pump and Hydraboost returns together into the single 72 pump return inlet. I’ll add some links from my build thread that show more of how I did it with the hydraulic clutch on my SM465. Hydraboost is a must for a K with bigger tires in my opinion.
https://67-72chevytrucks.com/vboard/...=662879&page=7
Posts 159 thru 163 cover my swap

[68isgreat]

Originally Posted by 57taskforce

My K20 has a 5” lift and 35’s. I run hydraboost and it stops very well. It’s got a square body front dana 60 and rear 14 bolt with 13” drum brakes, for now; I have a factory rear disk axle built for it that I haven’t gotten a round to installing yet.

With the 1 ton square body brakes and the hydraboost i can lock the 35’s up if i want to too. I used the brackets for hydraulic clutch and hydraboost from captain fab here on the board. The hydraboost is from an 08 silverado and the master is the Napa replacement for a ‘72 K20. Power steering and Hydraboost lines are mostly Napa replacement square body stuff. I used the oe steering pump with a full flow return T to tie the pump and Hydraboost returns together into the single 72 pump return inlet. I’ll add some links from my build thread that show more of how I did it with the hydraulic clutch on my SM465. Hydraboost is a must for a K with bigger tires in my opinion.
https://67-72chevytrucks.com/vboard/...=662879&page=7
Posts 159 thru 163 cover my swap

Wow. I'm not sure any of that is within my capabilities, but I'll look into it. Sounds great!

[57taskforce]

It’s really not that hard, the plumbing is pretty easy, the biggest challenge is mounting the brake booster to the fire wall, and the brake pedal to the booster rod. The mount plates from captain fab solve mounting the hydraboost and the pedal rod just depends on what you get your hydraboost from. Most hydraboost units have metric fittings so you have address that with on the 67-72’s which have standard inverted flare power steering fittings. It’s really not as bad as it might seem.

[68isgreat]

Originally Posted by 57taskforce

It’s really not that hard, the plumbing is pretty easy, the biggest challenge is mounting the brake booster to the fire wall, and the brake pedal to the booster rod. The mount plates from captain fab solve mounting the hydraboost and the pedal rod just depends on what you get your hydraboost from. Most hydraboost units have metric fittings so you have address that with on the 67-72’s which have standard inverted flare power steering fittings. It’s really not as bad as it might seem.

That makes sense. I didn't realize it ran off the power steering system. My ps is from a 1990 suburban with the serpentine system and a square body ps box. That all sounds doable. I looked online and hydro boost systems are pricey, but doable. Worth it if it works as good as you say.

[57taskforce]

Originally Posted by 68isgreat

That makes sense. I didn't realize it ran off the power steering system. My ps is from a 1990 suburban with the serpentine system and a square body ps box. That all sounds doable. I looked online and hydro boost systems are pricey, but doable. Worth it if it works as good as you say.

You can piece it together way cheaper from junkyard/refurb parts than the kits online cost. Square body lines can be made to work pretty easily especially if you already have a metric power steering pump like it sounds like you might.

[68isgreat]

Originally Posted by 57taskforce

You can piece it together way cheaper from junkyard/refurb parts than the kits online cost. Square body lines can be made to work pretty easily especially if you already have a metric power steering pump like it sounds like you might.

Great, thanks!

[LS short box]

I used a hydro boost on my 66 Mustang project. Bought the kit from Paul at Hydratech. Truly bolt on and worked super. It would put your nose up against glass.
Pic.

[68isgreat]

Originally Posted by LS short box

I used a hydro boost on my 66 Mustang project. Bought the kit from Paul at Hydratech. Truly bolt on and worked super. It would put your nose up against glass.
Pic.

Cool! I plan on using my truck on some steep off road trails, so this really appeals to me.