E34 Brake Sphere Gassing

[RSK540iA]

Hi all,

Has anyone ever modified and re-pressurized a 540i brake sphere? I find paying the equivalent of USD 500 somewhat hefty. What would the pressure be? I know factory units don't have the fitting but I see no reason why a hole can't be carefully drilled, a fitting welded in place and the unit pressurized as per spec. After all, their principle of operation is similar to spheres used on Citroens.

Would be interesting to hear your views.

Thanks in advance.

Ralf

[winfred]

i do beleave once the accumulator ruptures internally it's toast, it's not so much that it's lost pressure as it's not capable of holding it any more internally and it's gas leaks out while filling up with fluid

[Bill R.]

Its a rubber or some kind of plastic bag inside that metal sphere thats full of nitrogen under pressure and the hydraulic fluid is all around the outside of the bag, when the pump forces hydraulic fluid into the sphere it compresses that bag full of nitrogen so that even when the engine is off the system holds pressure in the lines because that bag is compressed.

When you get a hole or tear in that bag then all the nitrogen leaks out and you can't recharge it. The spheres here cost around 80US not 500... You might be better off ordering one from BMA and paying the shipping.

Hi all,

Has anyone ever modified and re-pressurized a 540i brake sphere? I find paying the equivalent of USD 500 somewhat hefty. What would the pressure be? I know factory units don't have the fitting but I see no reason why a hole can't be carefully drilled, a fitting welded in place and the unit pressurized as per spec. After all, their principle of operation is similar to spheres used on Citroens.

Would be interesting to hear your views.

Thanks in advance.

Ralf

[RSK540iA]

Hi Bill,

I just received a response from BMA. They want USD 299 for the sphere, plus USD 77 for shipping. To that I must still add duties and VAT once it goes through Customs. It may work out more than the equivalent of USD 500 once it's cleared Customs. Do you have a cheaper source?

Thanks.

Ralf

[Bill R.]

Thats BMA and independant parts house not bmw of america. They are new parts and they have shipped to many of the members here in Australia and New Zealand so i would imagine they'll ship to South Africa as well. I don't know what the story is on import duties though. Here's the link to their website

Hi Bill,

Thanks for the price info. Would USD 80 be for a new sphere? As mentioned the local price is R 3,195 + 14% VAT (+- USD 500). I assume the American spec sphere would be the same as the South African spec? Will BMWA ship to South Africa?

Thanks,
Ralf

[RSK540iA]

Thanks for the link Bill. I've submitted my enquiry, let's see what they say.

Ralf