Brakes: Alternative to Hydrovacs

[Steve Winzar]

Hi All
At present there is a thread running where a few contributors are voicing their frustration at the apparent lack of longevity of their Hydrovac power brake boosters. I decided to not make comments on that thread, but rather open a new one. Some comments relate to replacing the Hydrovac, but with what? I reckon I've got just the thing!. Over here in Australia, our studeys (largely) don't have 'em- we have something else. You could easily replace your Hydrovac with one of our PBR VH-40 or 44's. These are pretty much bombproof and were, and continue to be used, on a range of early Australian made GM Holdens, Ford falcons & Fairlaines, Chrysler Valiants, AND... CKD Studebakers. I reconditioned my own recently for only $120 although I had to scrounge parts. The upshot is that these units are reconditioned to new standards by Bosch Australia (but they won't sell ya parts!) and a number of private companies. The VH-40 is supposedly for disc brake cars but I had one on a 64 cruiser with drums and it was plenty potent. The 44 shown below is from the 62 Hawk I acquired some months ago and is smaller.
Here is a fer-instance

https://www.ebay.com.au/sch/i.html?_from=R40&_trksid=p2054436.m570.l1313.TR0.TRC0.H0.Xpbr+vh40.TRS0&_nkw=pbr+vh40&_sacat=0

Now I know you blokes in the USA will all probably think this is a bit amusing, but just consider us Aussies, Kiwis, Sth Africans etc...we buy all our parts from overseas (gee, wonder where from..? ) so investing in a VH-44 or the bigger 40, isn't as silly as you might think. The Australian dollar is getting only $0.78 lately so you will get a pleasant break on the exchange rate.
Bombproof, mate !
Steve

[JoeHall]

I would try one of those in a heartbeat, if the HV that is currently on the GT ever gave me problems. So far, knock wood, it is doing its job well. It is one of SI'srepros, now about three years on the car, if memory serves.
Thanks for coming up with an alternative !

Joe H

[bensherb]

Some years ago those boosters were very common and easy to come buy here. They were marketed for use in street rods and alike in all the magazines and catalogs. I started looking for one about a year ago but nobody here sells them anymore. I did find them available from Australia a few months ago but they are generally quite expensive. At least when compared to a standard type booster. If you shop around you can get the drum brake version at a reasonable price though.
Unfortunetly, they don't offer one for four wheel disks, which I'm swapping the finned drums for so I'll be changing to a lark swing pedal and mounting a booster and master cylinder on the firewall of my Hawk.

[Mike Van Veghten]

Hint...smaller diameter master cylinder piston.

NO booster required. Just do a little reading about brakes. I have four wheel disc brakes on two 54 Studebaker cars, neither have any sort of power booster, just the "correct" sized master cylinder. They both have different (but similar) systems, a two toe push is all it takes..!

Mike

[bensherb]

What size master are you using, caliper sizes, etc? My system originally had a 1" master and 9" single booster on the car it came from. I just don't want the pedal too hard to push, because of my knees, but still need to move some fluid. Currently I'm planning on a 7" dual booster (for clearance) and the 1" master. The 7"dual booster should (per the math) supply a bit more force than the 9" single one, so a bit less pedal effort than the original donor car had. And yes, the pedal advantage is the same as the donor car.

I did think about trying a 15/16" master though, but it is necessary to move a certain amount of fluid and this system was designed for the 1" master cylinder.

I have built systems with 4 wheel disks, and 4 piston calipers, (16 pistons) that worked extremely well with no power assist.

[Steve Winzar]

Thanks for that info, mike, I've often wondered about the upshot of a smaller bore on Studes. Are you using 15/16" or even less?

[Steve Winzar]

Hi bensherb- I'm not sure your rationale for the 7" power brake 'Drum' is correct. I have a VH-40 pictured in my original post but also have on hand my old Cruiser's 9" VH-40 unit. The larger diaphragm unit will supply far more 'assistance' than the smaller one. Hence the edict over here that the bigger Power Brake Servo was meant for Disc brake apps (but worked bloody well on my Stude's drums!).
I had a belief that PBR actually sold these into Canada at some stage. Yeh, a bit of a shame Repco et al want near $400 = for 'em but you can get these for less and there is a private reconditioner who is plenty fairer. Don't forget that you would pay way less in US dollars. I will stand by my original quote in that these units will LAST.
Steve

[bensherb]

True, my dad's 1950 Ford has one on it; it was there when he bought it over 15 years ago. It has front disks and with the 7.5" VH-44 the brakes are good but you wouldn't know they were power assisted. Still working fine though and never a problem with it.

When comparing the VH-44 to the VH40, both single diaphragm's, with the same input pressure of 450psi, the 7.5" VH-44 will put out 820psi, where as the 9" VH-40 puts out 1470psi. (from their posted specs)

I don't think you understood my statement about the 7" booster I mentioned. The 7" booster I mention is a dual diaphragm model. When compared to a Single diaphragm 9" booster it offers around 45% more diaphragm area and thus more pressure. A 7" dual diaphragm booster is closely equivelent to a 11" single diaphragm booster.

[Steve Winzar]

Pardon bensherb- Sorry, I wasn't familiar with that arrangement but it sound s a good bit of gear. 15 years + eh?.... they last don't they! Interesting you say the VH-44 makes the brakes feel somewhat unassisted, because that was the feeling I got after I went to the trouble of overhauling it. I suppose it's better than face-planting the windsheild, like the VH-40 used to be liable to do.
Steve

[bezhawk]

A hydro-boost that works off the power steering system also is a good alternative. Any style or size master cylinder then can be used. It takes up very little space, and will work even if there is not much vacuum.

[stude dude]

My experience is that Bendix Hydrovac boosters are more serviceable, desirable and probably a more affordable alternative to the PBR VH40/VH44 boosters.

Chris.

[t walgamuth]

What size master are you using, caliper sizes, etc? My system originally had a 1" master and 9" single booster on the car it came from. I just don't want the pedal too hard to push, because of my knees, but still need to move some fluid. Currently I'm planning on a 7" dual booster (for clearance) and the 1" master. The 7"dual booster should (per the math) supply a bit more force than the 9" single one, so a bit less pedal effort than the original donor car had. And yes, the pedal advantage is the same as the donor car.

I did think about trying a 15/16" master though, but it is necessary to move a certain amount of fluid and this system was designed for the 1" master cylinder.

I have built systems with 4 wheel disks, and 4 piston calipers, (16 pistons) that worked extremely well with no power assist.

I've done this a few times. Also have increased wheel cylinder size on my 71 Bronco once....that works too.

[Steve Winzar]

My experience is that Bendix Hydrovac boosters are more serviceable, desirable and probably a more affordable alternative to the PBR VH40/VH44 boosters.

Chris.

Hi Chris. In the instance that parts are drying up for the VH-'s I can see your point. I found the overhaul on my unit pretty straightforward, though- no probs.

[bensherb]

Back when the VH-44 was put on my dads car, they could be bought new for $150 all day long here. Everybody was selling them. They began to dissapear around 5 to 10 years ago. I was surprised how hard they were to find now.

[go-studebaker]

Hi Steve,
It's been an absolute age since we met. I have one of those units in my garage at home here in the UK.

go to your PM area and I will send you my email.

Here in England there is a Lockheed power booster that is around £140.00 that does the trick that is a new unit. Loads of UK cars use them and they are better than the hydrovacs. More expensive than the Aussi units I know but it saves the brutal postage costs and import duties to and from America to get a change over unit.

It also depends on weather you wish to stay original if you have an imported LHD car or not.

Regards
Greg