Brake bomb

[SteveM]

A CS in Virginia sold on eBay today for $14,000. Amongst a myriad of changes from standard the owner had installed a brake upgrade he referred to as a Brake Bomb system. It looked like the sort of pressure system you might see in your domestic fridge!

Anyone have any clues to what it might be?

...of course I failed to keep the URL for the auction.

 

[x_atlas0]

The E28s and E24s used a brake pressure accumulator based brake assist system. It looks like a ball hanging from the master cylinder, hence the name "brake bomb". It also requires (based on my understanding) changing the power steering, as the pressure comes from the power steering pump, rather than the engine vac. pressure.

 

[Honolulu]

BTDT

Well sorta.

My '83 533i and '87 735i have that system. Rather than using manifold vacuum and a vacuum servo to provide power brakes, it is a system which uses hydraulic fluid pressure to augment the braking force.

System gets it's power from a high pressure power steering pump, and stores it in the "bomb" which has a internal diaphragm separating ATF from a chamber filled with nitrogen. Pump pressure is stored in the bomb and released/used to augment the braking system.

The bomb itself is not particularly reliable, but overall the system works well. The bomb system is commonly fitted by those using Motronic engines, who don't want to source an Ljet manifold and adapters, or a tii brake booster. The latter are getting a little hard to find I suspect. Advantage to the bomb system is that it's easily available from the engine donor car. Particularly if you relocate the battery to the trunk there is easily enough room to fit the bomb and hoses.

 

[velocewest]

Right that. No need for a different PS pump, though. It just feeds to the brakes first, then on to the steering box.

My Rover has hydraulic brakes too, but they are charged with an electric pump that sits on the fender. Same "brake bomb" accumulator. I've got all the hydro brake kit off an e23 I intend to use on my e9 when the turbo engine goes in. Vacuum brake boosters don't mix well with positive manifold pressure.