Hydro boost brake boster question

[toms57]

Are the hydro-boost brake boosters that are becoming increasingly popular available as a salvage yard item, or should I just plan to spring for a new one?
What are they originally out of?

Thanks, Tom

[Rick_L]

You can do it both ways.

The most popular unit for our cars is one from a 90s Astro van, but others will work.

I got a brand new unit of Ebay for $60.

[toms57]

Rick,
Is this the same unit that retailers are selling in the $450.00 range without master cylinder?

[Rick_L]

I don't know what every one of them sell, but it's what some sell. For $450, you should be getting a bit more hardware, for instance it should have a mounting plate for a 55-57, a modified pushrod with a clevis that will mount to your brake pedal, etc. But if you're handy you can do all that yourself and save a lot of cash. Plus there's no assurance that the pieces they sell you will fit without mods.

[markm]

Plus there's no assurance that the pieces they sell you will fit without mods.

Rick, that the understatement of the day.

[chevynut]

I think I paid $100 for a brand new on on eBay. I noticed an article in PHR this month (April issue) that CCP is selling kits now.....they say they're for those "on a budget". They're $750-899. The Hydroboost alone is $389.

I sell laser cut steel Hydroboost adapters if anyone needs one to bolt the hydroboost to their 55-57 or other cars with the same bolt pattern. That includes 58-64 Impalas, and the late 50's Olds, Pontiacs, etc.

[toms57]

I think that those are the kits that I have been looking at. Price seems pretty high if the booster itself is a $100. item.
My problem is that I don't have a feel for what other hardware is needed to make it all "right"...
I currently have a chrome Master Cylinder and Vacuum booster from CCI (I think). Will the MC be usable with the new stuff? I currently have front disc/ rear drum. Will this cylinder still work if I get to put disc's on the rear? I currently have a proportioning valve mounted directly off of the MC. Will it have to be different?
Lots of questions. Any input is appreciated.

Tom

[Rick_L]

The $60-100 units on Ebay are definitely going at a discount compared to other sources including the auto supply. Part of it is no warranty. The one I bought was definitely new/unused.

You should be able to use the same master cylinder if it was sized correctly. The only concern is whether the pushrod is the correct length, and you may need to modify so that it is.

The only deal with rear drums vs. rear discs relative to a master cylinder is the reservoir size. Disc brake master cylinders have a bigger reservoir. A drum/drum m/c will have 2 small reservoirs; a disc/drum m/c will have a big one and a little one; a disc/disc m/c will have two big ones. This is not the end of the world though. If you have a small reservoir, you just need to be picky about the fluid level. The other issue is that you can't use a GM combination valve made for disc/drum with disc/disc, as it has a residual valve in the outlet port for the rear brakes. You don't want a residual valve with disc brakes. The only exception to that is if the master cylinder is below the calipers, which is the case if the m/c is mounted on the frame, like in street rods and old pickups.

[toms57]

Rick, Thanks for your explanation. Are you saying that I can simply eliminate the proportioning valve completely? I can live with the size of reservoir's if they are not technically correct.

[Rick_L]

I personally like the combination valve in some cases but it's not a requirement. Some kind of proportioning valve is a requirement though.

[toms57]

Chevynut,
Is the adapter that you sell what I will need to adapt a hydra boost to my 57. Is everything else something that I can make with materials sourced locally? What do you get for it?

[chevynut]

Tom57, the only thing I sell is the adapter that allows you to bolt the Hydrobooster to your firewall. The adapting of the pushrod to your 55-57 brake pedal is up to you. It's not hard to make everything work and I can show you how I have done it with the stock linkage. Check out my website below. I have two different versions of the adapter.

[toms57]

Am out of town this week. Will look at the website and get with you when I get back.

[toms57]

Will these hydroboost units work with the same system that is powering a 500 series power steering box. Will one pump be OK for both or is something else needed?

[Rick_L]

You use the same pump. The high pressure line goes to the hydroboost first, and then to the power steering box (or rack). The return line from the hydroboost tee's into the return line from the box. There is an orifice in the return line fitting on the hydroboost; that fitting is supplied with most h/b units.

[toms57]

I am seeing a lot of these units posted saying from dodge trucks and others. Are they all the same unit or do I need to stay with an Astro Van specifically?

[JT56]

What is the pros and cons with a traditional h/b vs the one with electric motor? I remember Cnut had one on his car at one time?

[chevynut]

If I could have used the Bendix Hydroboost I would have done so. It's more readily available and is a proven system that's used in many vehicles today. I have one in my Silverado and I love it. The ABS Power Brake electric booster is fairly expensive, not well supported, and is not used by any OEMs that I know of. My desire was to "hide" my brake system, and not put it inside the car. It ended up under my driver's side inner fenderwell, and the Hydroboost wouldn't fit there because it was too long and my tire would hit it. So I went with the electric system from ABS Power Brake and it solved the problem.

The main difference is that the Hydroboost is powered by the power steering pump. The ABS unit is powered by an electric pump. The electric pump actually compresses brake fluid which is used to drive the booster and uses the same reservoir as the master cylinder. The pump only runs when pressure in the accumulator drops to a certain level, otherwise it's off. It's supposed to supply up to around 25 actuations of the pedal from stored pressure. It's a self-contained system that doesn't depend on anything else on the car but the battery.

I have read several good reports about the ABS Power Brake electric booster in magazines and online. The choice to me depends on whether you have power steering or not, or whether you want to add it. The ABS setup lets you have power brakes without power steering. I like the clean look of the ABS setup even if mounted in full view on the firewall, but you also have to figure out where to put the pump. Both systems work well on engines with low vacuum where the cheaper vacuum booster fails.

[JT56]

I know there are other issues with remote canister ps reservoirs...does the h/b help with this or can it be more of a problem? My current setup is the P series Saginaw pump, which I do not like. When going to this ProCharger, I will most likely need a remote ps unless a type II pump could work.

[Rick_L]

I'm not clear on all the pump nomenclature you mentioned, so I won't go there. A hydroboost is fairly sensitive to air bubbles and foaming, so it's not forgiving if you have that type of problem. It's sometimes difficult to bleed the air on a hydroboost. Non-OEM remote tanks often have porting and baffling problems which can be the cause of that kind of stuff. If you need a tank or are building one, it would be good to study how the OEM remote tanks are built.

I have also seen reports that a small p/s cooler will help out. Not sure why some installations are sensitive, but the cooler seems to help some.

A couple of comments on the ABS system with the electric pump. It is an adaptation of the Bosch system used on some Turbo Buick GN cars, and cursed by many owners. Those cars also used hydroboost sometimes. If you mount the electric pump so that it's isolated from the body, that reduces noise a lot. The system seems to work well when it's working.

[toms57]

I am back to the build part that has me hooking up all of the parts that I have been accumulating all winter. I am now hooking up the hydra-boost system where I formerly had a vacuum booster.
When I previously installed the vacuum unit, I had to drill another hole in the brake pedal arm. Now that I install the hydra-boost unit, do I use the original hole or the hole I made for the vacuum system?
The original seems to line up better. The lower hole has the rod dragging the housing as the pedal goes full stroke. I think that the original would have no interference.
Any Input appreciated.

[56-210Sedan]

From all the one's i have seen done the original hole lines up the best, but i have never seen anyone have to move it to another hole other then the original spot.

[Maddog]

iS THE HYDROBOOST SITTING LEVEL OR AT AN ANGLE? if LEVEL USE UPPER (ORIGINAL) HOLE

[chevynut]

Mine lined up best with the original hole in the brake arm before I decided to go another route. The pushrod ends up being pretty short, so it needs to line up well. You can use a larger bore master cylinder if you get too much pedal travel, since the booster is very effective. It all depends on what brake calipers you have.

[toms57]

It is level. The original hole seems to line up better.
Was there a reason for the lower hole other than line up?
I always thought that it had to do with leverage or stroke of the pedal.

[Maddog]

POWER BOOSTER WAS DESIGNED USING A DIFFERENT PEDAL RATIO, THE RATIO IS CHANGED BY MOVING THE PIVOT POINT ON THE PEDAL ARM

[toms57]

Went out this evening and had to shorten the linkage to allow me to use the original hole. It all fits better and looks and feels better.
I hate the hassle of doing and re-doing, but that is the name of this game. You have to keep at it until you get it right.
Thanks for the help.

[Rick_L]

I mounted mine 1/2" down. The idea behind that was to be able to use either the stock pedal ratio of 6:1 or a modified pedal ratio of 4:1 (clevis hole in the pedal arm 1" down) with only a little bit of angularity on either. We'll see how it works out.

[toms57]

On mine 1" down had the rod hanging up on the housing when the stroke had the pedal nearing the floor (which you probably would never encounter), but it did get to the point that the rod hit solid against the housing instead of bottoming out the
MC piston.
1/2" will probably be OK, but I would look it over real closely.

[shua57]

I did this conversion many years ago on my 57 so forgive me if I can't remember all the info. I bought a hydrobooster from a used 1 ton GM box truck (like a frito lays truck). The brake arm was adjustable so it basically was a straight install and no modifications to the brake pedal was required. I attached a 70's Vette mastercylinder, plumbed it, installed a PS pump with the double ports and was done. Stops great and I spent more on the stainless lines than I did the hydrobooster. My build is on another site. Oh the bracket, I took a 1/4" plate of steel and cut the shape I needed out, then drilled the holes for the stock bolt hole locations. Installed the bolts, cut the heads off and welded them...tada, custom one off hydroboost bracket.
Josh

[mrbelair]

I was considering using an electric powersteering pump (from some Euro car)
and thought about using it to power the hydroboost at the same time.
I found this video from someone that made the same set-up.
What are your thought about this? Can it be done?
and if so why is this the only example I can find on the internet


https://www.youtube.com/watch?v=PvqNKTVh5L8

[chevynut]

If that electric pump can put out enough pressure there's no reason it won't work.

[Rick_L]

The "other" non-vacuum power brake system (made by Bosch and originally used on Buick GNs) works well when it works. That system is known for reliability problems. It's a bit noisy too, but you can help that with isolation mounts. The aftermarket version is sold by ABS.

That system has a relatively low flow pump along with an accumulator. I don't think it's anywhere near enough volume for power steering.