View Full Version : TR2/3/3A TR3A Front Brake Caliper Choice

12-16-2009, 08:29 PM
Hi guys,

Thought I would post a quick question. My "Good" car and my parts car have two different types of brake calipers installed.

Parts Car. I am assuming that these are correct for a 3A?


"Good" Car. I am assuming that these are off a 4?


The question is, is there a difference between the two calipers performance wise? Pros and Cons? I am leaning to using the parts car calipers as they seem to be in a little better condition.

M. Pied Lourd

12-16-2009, 08:53 PM
The change point was during the TR3A run, so your 'good car' calipers are probably from a later TR3A. They were only used at the very beginning of the TR4 run (until the rotor size changed from 11" to 10-3/4").

Functionally, they are pretty close to identical, use the same hoses, pads, repair kits, mounting bolts & pistons. Obviously the anti-squeal springs & pad retaining plates are different. ISTR they are slightly lighter, so there is some reduction in unsprung weight.

Note that the later 'split' calipers have an O-ring between the caliper halves. Girling's official position was to never split the calipers, so the O-rings are not included in any repair kit. If you decide to split them, you'll need to source the O-rings (which I believe are available separately from TRF et al).

12-16-2009, 09:30 PM
Ah ha! The infamous A vs B type caliper. Been there. Ordered the wrong one....

Don Elliott
12-16-2009, 09:46 PM
Dave - My early TR3A (TS 27489 LO) has calipers similar to your parts car with the one-piece casting and the steel pipe from the inner chamber to feed the outer piston.

12-16-2009, 10:27 PM
Is the A type (I've those on my '56) also used with 10 3/4 in discs?

I thought they were only mated to the 11 in variety.

12-17-2009, 10:00 AM
Hi Guys,

Thanks for the responses. I will go with the ones from my parts car and keep the others for back up.

Randall, yep been there on the "splitting" issue....split them on the TR, replaced the little O Ring and have had no issues.

M. Pied Lourd