10 replies to this topic

[Pat Clarke]

In 1976, Tony Rudd famously issued a 48 item direction to the Designers at Team Lotus.

 

Number 30 on the list was  "Brakes recuperate better with a head of fluid above the master cylinder. Low mount the cylinder with a a high separate reservoir, with a big enough pipe. And don’t forget the scent spray. Always pressure bleed".

 

What is the 'Scent Spray' he refers to? Is it just shop jargon for a hand held pressure bleeder or is it something else entirely?

 

Just curious.

 

Pat

 

Edit...typo :-)

Edited by Pat Clarke, 14 January 2018 - 22:41.

[lyntonh]

My guess is a tell-tale for leaks

[eldougo]

The sent of Brake Fluid especially when it hot ,give off  a lovely smell.

[Dipster]

The sent of Brake Fluid especially when it hot ,give off  a lovely smell.

It also has a distinct taste. Useful for identifying fluid leaks.

[GreenMachine]

This has come up previously, but my search abilities are not up to the task     ...

[Catalina Park]

He is referring to airflow over the vent hole in the master cylinder cap sucking all the fluid out, just like the way a scent spray bottle works.

[Doug Nye]

Precisely right Catalina...  The 'scent bottle effect' as Tony called it.  Pass an airstream over a small orifice in the cap of a bottle containing fluid and some of the fluid will be drawn up into the low pressure area created by the airflow, it will atomise and flow back within that stream.  BRM had encountered the problem, causing "mysterious loss of fluid" which led to laborious, time-consuming, and fruitless leak checks throughout the hydraulic system...until someone twigged what had really been going on.

 

DCN

[Pat Clarke]

Thank you gentlemen, curiosity satisfied

 

Pat

[Cirrus]

Precisely right Catalina...  The 'scent bottle effect' as Tony called it.  Pass an airstream over a small orifice in the cap of a bottle containing fluid and some of the fluid will be drawn up into the low pressure area created by the airflow, it will atomise and flow back within that stream.  BRM had encountered the problem, causing "mysterious loss of fluid" which led to laborious, time-consuming, and fruitless leak checks throughout the hydraulic system...until someone twigged what had really been going on.

 

DCN

... and the solution used to be to take the cap off the reservoir and put a condom over the neck of the reservoir, letting the condom drop into the fluid. When the cap was replaced the fluid level could rise and fall but the condom ensured that no fluid leaked out.

 

The brake manufacturers eventually produced a rubber bellows which performed the same job and looked a bit more professional.

Edited by Cirrus, 16 January 2018 - 17:41.

[Ray Bell]

I think that was a much earlier solution, Alan...

Those condom-like barriers existed in the sixties.

An interesting one was the problem struck by Frank Gardner in the ex-Stillwell Brabham. After a hasty repair to the car's nose, they constantly had brake problems, I think it was over three or four meetings.

At Lakeside it happened and he was able to get straight into the pits. There they found a strand of loose fibreglass in the vent hole.

[f1steveuk]

Exactly the same way some carb's work, air speed over a tiny opening pulling fuel into the venturi