View Full Version : TR2/3/3A Rebuilding brake sys on 55 TR2

12-05-2009, 10:41 AM
I am in the process of rebuilding my 1955 tr2 Brake system
(been in my family since new.) trying to find out if brake line fittings are pipe size or regular american standard threads.I want to make sure all fittings get rethreaded (checked and cleaned).
Bought new rubber lines for front and rear and want to make sure everthing fits

John K
1955 TR2
Boston ,Mass USA

12-05-2009, 11:00 AM
There is a mixture, but I believe they are mostly SAE straight threads. The only 'pipe' threads I can think of are for the brake light switch.

12-05-2009, 11:06 AM
Hi John - welcome!

If you sourced the lines from Moss, TRF, or VB you should be all set.

I can't confirm the thread sizing, but I'm sure someone here will be along to do that soon.

Keep us posted on your progress, and we like pictures around here (hint, hint).

12-05-2009, 02:11 PM
Just a suggestion to make life easier in the future, a cheap dial caliper and a thread pitch gauge (https://en.wikipedia.org/wiki/Thread_pitch_gauge) can help you to determine what threads you are dealing with. Takes the guesswork out, and can be picked up for a few dollars. I have a couple of sets...SAE and metric. If it don't fit one of those, then it's most likely British Association. The only two BA sizes I have run across on my TR3 is 2BA and 4BA. Here's an article and chart about BA threads. (https://www.britishfasteners.com/threads/)

Edit: in a pinch, you can use the taps themselves to confirm what thread you're dealing with by using the tap as a thread pitch gauge. I do that with my BA taps, as I haven't come across a BA thread pitch gauge, and even if I did, since I'm only dealing with two sizes, it wouldn't be worth buying.

Andrew Mace
12-05-2009, 03:36 PM
John, I'm not quite sure just what all the threads are. However, if this is the original Lockheed all-drum system (as opposed to the disc/drum Girling system of later cars), I'm pretty sure the threads are different between the two systems. Later Girling systems do seem to be more SAE, I think.

I ran into problems many years ago trying to restore the Lockheed system in my Mayflower to correct, original configuration, and I almost ruined a brand-new hard line and fitting until I discovered that one of the many cobjobs on the car had been to toss in whatever brake junction fittings a previous owner could find either on the bench or under an old Plymouth or ?????

Meanwhile, I think pretty much any of the fittings you might need are still available new, so I'm not sure I'd bother with trying to clean up anything that doesn't look pretty good already! And one other bit of advice for whatever it's worth: any wheel cylinder that aren't good enough to be rebuilt should be replaced with real Lockheed cylinders. I went through the brakes on a buddy's MGA1500 several years ago and tried to save him some money by obtaining aftermarket "reproduction" wheel cylinders. Yes, they were cheaper, and yes, they could be made to fit and function, but the fitting problems I had particularly with the rear wheel cylinders -- lots of filing of the body to make them fit properly -- convinced me that the extra money spent would've been worth it!

12-05-2009, 04:06 PM
Just a suggestion to make life easier in the future, a cheap dial caliper and a thread pitch gauge (https://en.wikipedia.org/wiki/Thread_pitch_gauge) can help you to determine what threads you are dealing with. :iagree:
In addition, some cheap eye loupes can be really helpful for seeing small errors in thread pitch.