Hydroboost conversion

85' 400i daily driver.

I am on my second vacuum booster in a year.

The first unit failed because the snout cracked. I can't imagine how.

On the second unit that's in the car, the valve keeps sticking creating a vacuum leak.

I'm considering converting to a Hydroboost system. Has anyone done this?

 

This seems like a good choice.

Just a new mounting plate and some hoses.

But, does anybody have experience with these units in a passenger car?

I have a similar unit in an IH truck but I've never driven a car with one.
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I have driven many cars with hydroboost. It works great. It has a harder pedal feel than a regular vaccum booster. Where did you find the setup? I think you would be pleased with it. It is hard to describe but the pedal has a lot more resistance when you push on it but the car stops pretty easy. I have had 5 or more cars with it.

 

I hear a lot of good stuff about http://www.hydratechbraking.com/ over on the Pro Touring forums.

Shiny Side Up!
Bill

 

What about the ATF?

My power steering system uses ATF but the Hydratech web site says not to use ATF.

"Q: What type of fluid should I use with my power steering system. I have been told the automatic transmission fluid (ATF) can be used?

A: OEM fluids from the dealer are the absolute best. You can use any type of commercially available power steering fluid that meets the specifications of your vehicle. You should not use any type of ATF as it may foam excessively when it gets warm. Please also be very careful not to accidentally use the wrong fluid in either the brake or the power steering systems as substantial systems damages will occur!"

 

Seems to me whoever is supplying your boosters has some 'splainin to do. Perhaps someone(else) to overhaul your existing unit rather than a lot of trouble to fit something not intended.

 

Interesting quote on the page "Super Chevy Magazine exclaims, "In our history of vehicle testing, we have never had a car stop in this short of a distance!" ".


hmmmm......I wonder if the boys at superchevy know the booster has nothing at all to do with stopping distance? ....or if they simply decided to lie to make a sponsor happy????


Not to say in anyway the unit doesn't work just fine, it probably does, but it can't and won't affect stopping distance.

 

Will this address the initial (what seems like 2") no-action part of the travel before there is any noticeable braking?
From what I've been able to find, that first part is a long valve action prior to pushing the plunger of the Master Cylinder itself. Ironically, the Boxer had more immediate braking before the Booster was rebuilt, leading me to believe that the pedal rod was already adjusted all the way out to take up the space of the valve. Maybe the Hydroboost could address the problem....maybe it really needs that totally different Booster with a different diaphram valve.

This page contains a nice animation of how it works which implies that the first part of the travel is simply that actuation of the valve:
http://auto.howstuffworks.com/auto-parts/brakes/brake-types/power-brake2.htm
Click on the "Apply Brake/Release Brake" arrow.

My only other alternatives seem to be finding a different Booster with a shorter, more modern valve, or maybe a larger bore MC (which would still have that long dead travel), or just going to a non-boosted, twin Master system.
The basic diagram:
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We sort of had this conversation in another thread recently. In theory it doesn't affect stopping distance. But in practice it might. If the modulation, the feel of the pedal is improved perhaps the ability to keep the brakes right at the ragged edge of maximum braking for the whole braking distance is improved so that actual stopping distance is better.

I'm not disagreeing - they probably are FOS and brown-nosing a sponsor, but given the benefit of the doubt, they could be right.