Vacuum vs. Hydraulic Brakes

[heffe608]

I'm in the process of swapping an LS into my 71 c10. I have heard that its best if you convert to hydraulic brakes when upping the power. Does anyone have an idea of at what point the vacuum brake booster becomes not enough? Maybe at a certain horse power The truck doesn't have power brakes to begin with so I am trying to decide between the 2 and the cost/labor difference is pretty huge.

[Steeveedee]

Power brakes that are assisted by vacuum will become problematic at a low enough vacuum level. This is usually associated with a wild camshaft. How wild do you expect to go? If you have non-power disc brakes already, you're done. You do have front disc brakes, right, as they came out in '71?

[heffe608]

I do currently have disc up front and drum in the back. Just the stock set up. It would be nice to have some form of power brakes when all said and done. I am going to go with a cam that is as aggressive as I can get away with without loosing streetability. I'm building a turbo for the truck as well. Trying to end up somewhere around 400-600 hp.

[Steeveedee]

How do the current brakes work? Can they haul you down from speed in a respectable distance, without standing on the pedal? Hydraboost has been available for a long time. Maybe you want to do that? Someone will chime in eventually with a minimum vacuum requirement for whatever your setup will be. My truck is bone stock, and I'm not really looking to go too wild with it, since I tow a travel trailer and HP takes away low end torque...unless the engine is big enough. I already only get 7 MPG towing; I'm not looking to reduce that!

[ls1nova71]

Originally Posted by heffe608

I do currently have disc up front and drum in the back. Just the stock set up. It would be nice to have some form of power brakes when all said and done. I am going to go with a cam that is as aggressive as I can get away with without loosing streetability. I also building a turbo for the truck as well. Trying to end up somewhere around 400-600 hp.

I think some of you didn't read the whole thread. If you missed this part, I don't see how a stock cam and factory booster are going to work for the OP.....

[heffe608]

They work just like you expect non power brakes to work... I live in Seattle so having good brakes is high on the priority list with in city driving.

[weq92f]

A stock vacuum assist setup with a suitable vacuum reservoir if necessary would be far less expensive than hydraulic ( 150+37+20shipping=207bucks ).

Worry about it later, after you've got your swap done!

-klb

[ls1nova71]

Originally Posted by heffe608

They work just like you expect non power brakes to work... I live in Seattle so having good brakes is high on the priority list with in city driving.

Your own words..... Like 57taskforce said, it doesn't have to be expensive. salvage yards are full of hydroboosts and for cheap. You're doing an LS swap, so it's not like originality matters, and if you want 600hp, don't cheap out on the only thing stopping you. You really cant have too much brakes. In my build thread I show how I did mine for not much at all, and it has what lines I used that are stock parts available at the local auto parts store. https://ls1tech.com/forums/conversio...-c-10-a-3.html Hope this helps.

[special-K]

You must be talking about forms of power assist because all vehicles have had hydraulic brakes since they stopped using mechanical in the '30s. I only know low vacuum to cause vacuum assist power brakes to be inadequate. If you need more braking power you should deal with that at the wheel end with upgraded calipers.

[heffe608]

Ive been using the wrong term. I am thinking of converting to hydroboost. So using the power steering pump for pressure rather then vacuum pressure.

[heffe608]

Hydroboost conversions are either very expensive or very labor intensive.

[57taskforce]

Originally Posted by heffe608

Hydroboost conversions are either very expensive or very labor intensive.

Not true at all. Captain fab on the parts board makes the plates to bolt the hydraboost to the fire wall. All you need is a hydraboost from the junkyard and a little plumbing and your in business. There’s plenty of threads on here on exactly how to convert over. I’m converting my K20 to hydraboost with a hydraulic clutch as we speak. It can definitely be done for pretty cheap.

[KQQL IT]

My 400 makes 9'' vacuum and stopped fine with a booster.
Since deleted and went back to a manual master cylinder.
Less bs under the hood

[davepl]

Originally Posted by heffe608

Hydroboost conversions are either very expensive or very labor intensive.

Mine was neither so far as I can remember. It's a GM truck piece that someone revalved. Hardest part was the metric to standard adapter on the steering box that I remember!

I wouldn't worry about a hydraboost unless you've got an enormous camshaft with no vacuum. If you do you'll hate your truck so much you won't drive it anyway, so it solves the braking problem on its own.

Normal cam and normal vacuum booster would be my suggestion.

[rvrfoot]

If you have a big can you will not have vacuum.

[KQQL IT]

Originally Posted by davepl

Mine was neither so far as I can remember. It's a GM truck piece that someone revalved. Hardest part was the metric to standard adapter on the steering box that I remember!

I wouldn't worry about a hydraboost unless you've got an enormous camshaft with no vacuum. If you do you'll hate your truck so much you won't drive it anyway, so it solves the braking problem on its own.

Normal cam and normal vacuum booster would be my suggestion.

Truest statement here.

[geezer#99]

Generally you need at least 14hg of vacuum for a booster.
You can use a vacuum can to help or use a vacuum pump to boost the vacuum if needed.

[Bigdav160]

Since the OP is starting with manual brakes I would suggest hydraboost. Easily found in the junk yard (mine was a fresh rebuilt off a Astro van for $35)and easily adapted. I spent perhaps another $100 in hose, AN fittings and adapters.

Finding an OE style booster and bracket will probably set you back at least the same.

[davepl]

That's true, if you're coming from manual and have to buy it all anyway, why not!

[weq92f]

I think OP is being quoted vacuum vs. hydraulic from a shop. This probably means bargain salvage yard parts are off the table in favor of high end new systems and a hefty premium over the cost plus whatever install pricing they choose.

In this case, I recommend OP leave it as-is for now and deal with it later, perhaps with the advise from the board regarding these less expensive options.

-klb

[heffe608]

I spoke to captain fab about his brackets and ordered from him. That takes the labor side out. The hydroboost itself is cheap from the junk yard. When I said labor intensive or expensive that was speaking from a place where your either paying wilwood $1000 for the set up ready to go or going to the junk yard then doing a bunch of fab work to get all the parts to come together. The brackets captain fab is making takes this from Id say about a level 6 difficulty down to about a 3 from what I ca tell.