Thread: Vacuum advance diaphragm failures

No idea other than you're getting sold complete crap. They're all subject to the same stresses, namely manifold vacuum. The reluctor plate it hooks to uses only the vac pod as a limit stop. I've bought about 10 of these for various customers, none of them failed while I was still looking after their vehicles.

Land Rover Discovery Defender V8 replacement vacuum unit Powerspark | eBay

Found the solution.
All the britpart,bearmach vacuum advances are likely made in the same Chinese factory.
I found a local guy that rebuilds vacuum units from his shed out the back.
He took two of the four failed units apart and both had the same fault.
During manufacture the two part metal bulbs are pressed down onto the rubber diaphragm and folded to seal the units.
Lucas, back in the day had nice finished smooth shells whereas the Chinese ones needed some finishing to take the ragged edges off.
Of course this has never been done so the shells act like a cookie cutter and the diaphragm doesn't stand a chance so any vacuum stretching Rips the rubber and renders it useless.
Since having one of these rebuilt,and a little attention to smoothing the edges and reseated over a new diaphragm all is well after many miles.
These things aren't cheap to replace,so if anyone has similar failures I'd suggest looking for a rebuild shop,(seems there are a few around in oz)that will rebuild the failed unit instead of buying the same poor quality,cheers westy

Ha ha, that's a good tip and it makes sense how they all failed.

I've had the same issue with a Lucas one I bought from Powerspark. Only had it in the car for 600km and when I checked it it was blown. I've got another on order and I'm hopeing it will last a bit longer.


If it dosen't last this time I might look at a complete Dizzy change. Powerspark has the Lucas unit for under 200 bucks.

One of the units i bought was from powerspark,granted it wasn't sold as original lucas from memory.
Unless its got "lucas" written on the bowl and serial numbers embossed on it,it's Rucas...
These copies have no distinguishing marks at all.

Originally Posted by westy1

Found the solution.
All the britpart,bearmach vacuum advances are likely made in the same Chinese factory.
I found a local guy that rebuilds vacuum units from his shed out the back.

Any details on him? Looks like I need one rebuilt.

My old 84 farm girl has revved its head off at idle for years because I thought the cost too much for a vehicle that only gets used a couple of weeks a year but a cheap repair of the existing one would be considered. It got shouted a new battery for last year's harvest after years of hand-me-downs. The worn-out tyres from a 99 D2 are still good though.

Hi There,My Local guy that does rebuilds is in Auckland NZ.Thats why in an earlier post suggested a google search in your local area,i found vacuum and distributor repair places over various oz locales.
Saying this if you are happy to send it he'll fix it and send it back,easy.
I recall him saying he does rare stuff from all over the world.
This is all he does,i've visited his workshop out the back of his house.
Quality Rebuilds
Peter Collins
www.qualityrebuilds.com
peter@qualityrebuilds.com

From memory he charged me 70-80 nzd,and this vacuum advance diaghram is still going soild.
He may even be able to alter the way the diaghram responds with a different compound rubber perhaps.
Cheers Westy