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Painless Power Brakes for E30 V8 swaps (Remote Hydrovac Booster)

February 28, 2021

If you’ve been researching doing a V8 swap into an E30, you’ll quickly learn that one of the major dilemmas is how to solve the brake booster problem.

With a V8 swap, there is no room for any kind of brake booster in the stock location.

In the early years, the solution was to use a E34 brake booster, by placing it behind the drivers headlight and running a long metal rod.


This method requires a good amount of messing around (cutting, welding, fabrication) and leaves you with a solution where if you get in a car accident, that long rod is going to be the first thing coming to say hello.



The E30 community eventually moved to using boosterless (manual brake setups). I was at the forefront of this back in 2014 with this post:


E30 boosterless brake bracket (booster delete) manual brakes for swap cars


The break through in going this route was that with 3 small bore MC’s (instead of 1) you could get in a much more reasonable range of pedal pressure.

The problem however, is that try as you may, you’ll still never reach full power brake comfort.


People early on were also experimenting with Hydroboost, which basically used power steering pressure to drive the booster. Early on this meant looking at systems like those found on the E23. It proved to be more problematic than worth for most.


This eventually lead to a hydroboost system you could get from Sikky, that they no longer offer, but could be plumbed fairly easily for LSx swaps.



So here we are, its 2021 and none of these options seem that great. Here is where we take the next step forward  to solving this problem once and for all.

Hydrovac is the answer! Its essentially a remote brake booster, that is easily plumbed in line to your current master cylinder lines and just needs you to run your vac line to it. It can be placed literally anywhere in the car.

This technology is actually not new at all, it was used on upgrading cars in the 1960’s that came from factory with manual brakes. Why haven’t many people used them in recent times? Because automakers leap frogged to using brake boosters directly connected to the master cylinders and to hydroboost. There were no reputable modern makers of hydrovac boosters, and many from the 60’s were either too old to trust, or single circuit so they could only run the front brakes.

The good news is that a Spanish brake company by the name of Iruna has started manufacturing dual circuit hydrovac units again!

Some places call it a “Dual Circuit Brake Servo” or “Dual Diaphragm Remote Brake Booster”:

Download (PDF, Unknown)


The units come in three sizes, from 5 1/2 which provides an OEM level of assist, all the way to 9″ that could stop a dump truck.



Installation is really as simple as it looks, you plumb in the lines from your MC into this remoter booster, and then into your calipers. The vaccum line you just extend from the same source your OEM booster was using.

Download (PDF, Unknown)


These units require around 16 in/hg to operate which is right inline with what the OEM unit use:


These units can be acquired stateside for ~$800, or from Europe direct for ~$500-600.




This system has gotten the attention of multiple project cars that would otherwise have no way of fitting a brake booster. Example:

Something to note is that some of these units sometimes run 3/8-24 SAE fittings (long type), so plan accordingly to buy a few adapters to bubble flare (metric E30 type), or when you’re making your brake lines just flare one end bubble and the other end SAE.

More pictures of the Hydrovac can be viewed here.

2 Responses to Painless Power Brakes for E30 V8 swaps (Remote Hydrovac Booster)

  1. Michel on March 10, 2023 at 12:43 am


    I am building a e30 m62.
    And was woundering if you sell these hydrovac system.
    And if you have working examples and pictures/videos of such a setup.

    Best regards.

  2. Aman on June 28, 2023 at 3:45 pm

    Which parts would be best to replace the master cylinder in the stock location?
    Would you runs Dual MC set up plumbed into the remote servo?

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