Brake boosters are designed to work with specific brake systems and are generally not interchangeable between different vehicles or brake systems.
Several factors can determine whether a brake booster will be compatible with a particular brake system, such as the type of brake system (e.g., hydraulic, vacuum), the size and shape of the brake booster, and the mounting location and configuration of the booster.
Generally, it is best to use a brake booster that is specifically designed and intended for use with the brake system on your vehicle. Using the wrong brake booster can result in improper brake function and potentially dangerous driving conditions.
Suppose you need to replace the brake booster on your vehicle. In that case, it is important to consult a mechanic or the vehicle manufacturer’s specifications to determine the correct brake booster to use.
It is common for brake systems to be designed as one unit. A “Mix & Match” approach is not something you can start playing right now and expect to achieve satisfactory results. Boosters aren’t the only thing that makes power brakes work.
Consider upgrading the master cylinder as well if you are going this route. It is a team effort. Look at how the pedal assembly connects to the master cylinder.
The brake pedal pushrod may need to be modified or fabricated if you use a different booster/cylinder unit.
Using a fabricated mounting bracket, the booster/cylinder must be mounted correctly and at the proper angle. It could work, except for that.
The master cylinder and its pushrod will differ from the standard brake system, as will the pushrod between the brake pedal and the booster.
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Classic Car Booster-Master Cylinder Combos
You might wonder which booster-master cylinder combination to choose when converting a manual brake system to a power brake one.
While some applications are pretty straightforward with just one option, there are plenty of cases where more than one option is required. Choosing the right conversion kit combo then becomes a matter of personal preference.
There are some options available to car owners here. Decide what you want to accomplish first. The following example is based on a recent phone call with a reader about their 1969 Camaro.
Questions to Ask Regarding Booster and Master Cylinder Combinations
Do you plan to convert to disc brakes? Is that the case, and if so, what type? Would you like to upgrade from the OE drum brakes to a more comfortable pedal feel?
You cannot have too much assistance in your disc brake system if converting to disc brakes, especially four-wheel disc brakes. There are, however, limitations.
We recommend a 9″ dual booster for our customer with a 69 Camaro. There is more than likely going to be a space issue with this particular car due to its big block engine and tall valve covers.
Our only option here is to use an 8″ dual diaphragm booster to reduce power assist slightly. Although this trade-off provides an assist, it does not produce the same level of control as the system with the 9″ dual diaphragm booster.
Classic cars have this drawback. Due to the lack of consideration for a brake booster, some are very space constrained.
How Does The 11″ Single Diaphragm Booster Differ From The 9″ Dual Diaphragm Booster?
In our booster discussions, we often get questions about what makes a certain booster different from another, such as a single diaphragm booster versus a dual diaphragm booster versus some other variation.
The larger the diameter, the more assistance it will provide. Before dual diaphragms were available, that was the case. Since there are two diaphragms inside, a smaller diameter can provide as much assistance as a larger one.
By multiplying atmospheric conditions by the booster’s diameter and by its number of diaphragms, you can determine the assistance provided by the booster.
As a result, the booster provides a certain amount of assistance. Although this is a simplistic approach, it gets you on the right track.
Final Tips
Use as many diaphragms as possible in the brake booster for disc brake systems to provide the most assistance. Be more selective about your choices regarding drum brake cars, erring on the smaller side to make driving more comfortable. In the end, we want to be able to drive them.