5 1/2 in Servo failure

[Dearg1275]

I was sat a a junction holding the car on the brake and something went BONG. The brakes immediately felt as if there was no servo. Zebadee and springs go bong, so unless that sprung joker was under my bonnet it could only be the big servo spring. I guessed the diaphram had torn.

Back home from a trip to Southam Mini metro centre all was revealed.

64A014DC-1637-4399-839D-36AC1A77BB4A.jpeg

I had rebuilt this a couple of years ago and the car it was then fitted to had only done a couple of thousand miles and had sat in the garage for 18 months. The diaphragm looked excellent when it all went together.

Needing a replacement I stripped an Italian 5 1/2 repro. This too had been sitting since last use 4 years ago. No joy there.

14EDC64A-B465-4D6D-B94E-EA7C0526841C.jpeg

My last chance was one I had built ages back before ethanol was added to fuel and that was as good as new. I can’t help thinking that this is another danger area caused by modern fuels. I have run servoed minis for years before ethanol arrived in our tanks and never had these problems. Both cars had the necessary condensation loop of hose to prevent fuel ingress into the vacuum chamber of the servo. Has anyone else suffered this way so quickly?

Worrying to say the least.

D

[Fanfaniracing]

WtF? Never saw something like that before!

[cmiller]

I have done many servos and have never seen anything like that. Can't offer any suggestions on this one.

Chris miller

[MiNiKiN]

By the looks of it, this rubber diaphragm has seen quite a bit of oil - AND: as we might know, rubber dislikes oil very much.

[Polarsilver]

"e" Petrol is evil stuff .. i would think fumes from this crap will attack original Servo rubber just the same as it destroys Rubber Fuel Pipe ..

[Dearg1275]

Whether oil or “e” fumes what do we do about it for the future? There are diaphragms available for the Italian made version from Alfaholics but are these any more resistant to attack?

On the oil front, I don’t really buy that as the clack valve on these cars was blanked off so the fumes could only come from the inlet manifold before ever encountering oil.

Perhaps I’ve just been unlucky and all will be sweetness and light. I just get the impression that life doesn’t really work that way.

D

[Polarsilver]

Perhaps its time to delete the Servo .. i did and have no issue with Brakes on two cars both are without the Servo,s .. but then i am not that concerned that everything has to be "original"