Tr3a brake light switch

[Rodbr]

My brake light switch has decided to operate in a yes no, no, no ,no ,no yes, no no method.

This points to dirt inside not a total failure. I do not want to go the normal method of fitting a modern one to the master cylinder box.

Is there a way to clean the inside with alcohol or similar. Suggestions on a card please.

If anyone has a spare original one they do not want or need??

Rod.

[Ralph Whitaker]

Only a fiver brand new from Moss.

[Rodbr]

Yes Ralph,

I know that but the modern generation of spares even form Moss are suspect I gather from elsewhere on the forum. I like to only do a job once if at all possible.

Rod

[stuart]

Extremely unlikely to be dirt causing failure more like just corrosion internally, just fit a new one but make sure you have the correct thread as there are two types.

Stuart.

[TwinCamJohn]

Agreed. They sent me the wrong one, which in a moment of stupidity I didn't notice as it will screw in. However, not efficiently and brake fluid pissed everywhere. Fortunately it didn't fail whilst I was out and about.

[james christie]

Not only are there two types of thread but also lucar and screw terminals. If they are £5 from Moss then they are overcharging. Must be one of the less reliable components of a TR, granted that it does sit a bit close to the exhaust down pipe.

I have vowed to myself that when the current one expires I shall fit the modern replacement on the brake pedal

james

[Rodbr]

Due to my recent vision impairment issue i find it difficult to assess close sighted things. is there a way to help me identify which thread i have fitted if I were to remove and take a piccy or something I can use to say same thread?

Are they identified by screw or Lucar terminal only?

Many thanks in anticipation.

Rod

Edited April 28, 2020 by Rodbr

[stuart]

They used to be available in both connect types and both threads parallel and tapered. Not sure whats available now though.

Stuart.

[Mike Graham]

I know you said you do not want to fit a switch at the MC, but I got frustrated with being unsure of brake light performance, and installed a switch at the pedal. It is essentially “invisible” and now one less thing to worry about. Cheers, Mike

[ijonsson]

1 hour ago, Mike Graham said:

I know you said you do not want to fit a switch at the MC, but I got frustrated with being unsure of brake light performance, and installed a switch at the pedal. It is essentially “invisible” and now one less thing to worry about. Cheers, Mike

 So did I

 

[BlueTR3A-5EKT]

4 hours ago, ijonsson said:

 So did I

 

Excellent modification

Peter W

[BlueTR3A-5EKT]

On 4/28/2020 at 11:59 AM, Rodbr said:

Due to my recent vision impairment issue i find it difficult to assess close sighted things. is there a way to help me identify which thread i have fitted if I were to remove and take a piccy or something I can use to say same thread?

Are they identified by screw or Lucar terminal only?

Many thanks in anticipation.

Rod

Which brake system Rod?  Girling where it screws into the brass 5 way block by the exhaust pipe or Lockheed where it screws into a through drilled banjo bolt.

I think I have samples of both in the 'brakes' drawer.

Cheers

Peter W

[Rodbr]

Hi Peter,

It is a Girling system and is indeed the block by the manifold. I did make up a heat shield to lesson heat transfer.

[Ralph Whitaker]

Hi Rod, I believe it will be UNF the same as a standard brake pipe union as all the tapped holes in the brass union block are the same thread.

Ralph

[BlueTR3A-5EKT]

Done a bit of digging and 'phoned a friend'  -who said - "its a 1/8 BRIGGS ( nptf ) 27tpi thread.  Over the last 20 years **** switches have been made in various countries The tapering thread often too thick too soon and metric to 28 tpi for the sake of it."

Lockheed used a 1/8" Briggs taper thread  (nptf) with  27 tpi  - no sealing washer required as this item self seals.

Girling used 3/8" x 24 UNF parallel thread requiring a copper sealing washer between the switch and threaded union.

Cheers

Peter W