Midget master cylinder

Post by **leyther8008** » Fri Apr 11, 2008 3:41 pm

Has anybody looked if you could use a midget master/clutch cylinder as a twin circuit master cylinder in a minor? it looks to fit inside the chassis leg like a minors but has twin bores one for clutch one for brakes, I was thinking it wouldnt be two hard to make up a 'crossbar' link and use both cylinders as brake masters one for each circuit.
I might add this is only a thought after seeing a picture on the internet, I dont know if it will physically fit. but if somebody has already been down that path.
Like this one, dear I know but it illustrates my line of thought.
http://cgi.ebay.co.uk/TANDEM-Master-Cyl ... 0235479113

Post by **MoggyTech** » Fri Apr 11, 2008 6:20 pm

Sounds like a good idea but for one tiny problem, namely brake balance. If you think about how hydraulic forces act to increase brake effort, then try to get two master cylinders to do this in sync, it's a disaster waiting to happen.

When circuit A needed adjusting due to shoe wear, but circuit B was already close to lockup, circuit A cannot receive more brake effort, as circuit B is already hydraulically at it's limits, and as the brake pedal is linked to the two cyliners, it will be impossible to apply more effort to the circuit needing it, without locking up the other circuit.

Post by **Matt** » Fri Apr 11, 2008 6:45 pm

Also spridgets have the brake and clutch master cyl in a pedal box above the drivers feet

Post by **eastona** » Fri Apr 11, 2008 7:03 pm

later midgets had a twin/split master cylinder to give split (front/rear) brakes.

If you fit two singles in tandem, some kind of brake bias setup would be required I guess.

Not worth it really.

Andrew

Post by **bmcecosse** » Sat Apr 12, 2008 9:06 pm

Could be done I'm sure - an adjustable balance bar would be required between the two cylinders - but what's the point! If you think the rear brakes are getting too much pressure - just fit a pressure limiting valve. This of course can happen when discs are fitted at the front - with a servo, then the rear brake pressure can go so high it locks the rear brakes (very dangerous) before enough pressure is applied to the discs to do a good job of slowing the car!