Lotus Elan and Lotus Elan Plus 2 Forums

Dear All

I know on my plus2 there are two types of caliper available,the p16 and p16b,but does anyone know the differences.

I understand the pistons are different(are they interchangeable?)

If i have a sticking piston,is this rust?

What should the clearance be?

Are stainless pistons a good bet?

I believe TT does ali. ones-any comments?

Thanks in anticipation

John

there were dust boot changes, but I think that relates to the piston more than the caliper. Could be the late ones had metric threads.

Stainless pistons are the only way.

pistons should be a free fit in the caliper bore as the piston rides on
the "o" ring or seal in the caliper body. since the piston seals
against a rubber ring the outer surface of the piston is critical to
leak free operation. perished dust boots allow dirt and grit to attack
the exposed portion of the piston and greater exposure as the pads
wear. internally the brake fluid absorbs moisture, being heavier the
moisture collects at low points in the system like the bottom of
cylinders and low point of calipers where it does cause rust of steel
pistons or corrosion of alloi pistons.

in the calipers examine closely the recess the where the large seal
fits as the integrity of the groove affects the support of the seal.
the pistons should be examined for any signs of pitting or corrosion. I
use with a bit of fine emery to polish the piston surface and will
discard pistons with surface pitting.

stainless is a good bet, alloi being subject to the corrosion of
moisture in the system but hold up well when system is flushed on an
annual basis, some alloi are better able to withstand corrosion than
others...and not on a humid day best bet is phenolic which insulates
heat between the pads and the fluid.

I'm not an authority on the P16 calipers but I believe the difference
to be in the manner of securing the dust boot to the piston where the
type B boot id mates to a groove in the piston where the earlier ones
are secured with a wire ring. I believe the pistons are interchangable
when used with appropriate boots.

cheers,
Scott

John,
When I chucked the servo off my Sprint last year I fitted +2 calipers & discs, so I had to do some research- there are actually 3 types of calipers, an early one (don't know the designation) the P16, which is what I got, and a Metric threaded one on the later cars- presumably the P16B?
If you talk to Classicar Automotive at Chelford, they know all about this stuff and were very helpful, they mentioned the difference in the rubber gaiter, which I think is between the first type and the P16. The calipers are from the Triumph GT6, I found Rimmer Bros were also very helpful when I sourced the anti-squeal shims from them.
Agree with the comments about stainless steel pistons, btw.

Cheers,
Pete- see you at Donnington?

Gidday,
Original would have been P14, then P16 and M16 which is the same but with Metric threads.
See ya, Les

Les
I disagree, the M16 is a bigger caliper, using bigger pads than the P16 and yes it does have metric threads
This caliper was used on the Escort Mk2, Cortina Mk 3, 4 & 5 and also on the Capri
Arno

Gidday,
Original would have been P14, then P16 and M16 which is the same but with Metric threads.
See ya, Les
----- Original Message -----

I dunno bout numbers, but all +2 calipers are the same size

Are the front pistons the same as the rear ones?

e s <***@***.***> wrote:
I dunno bout numbers, but all +2 calipers are the same size

I thought the P14 was fitted to the 2 seaters only
or did they see fitment on the very very early +2?
My '70 model has P16B fitted.
The metric caliper was not used until '72 or so?
Cheers,
Scott

no

Gidday Arno,
So be it, we disagree.
See ya, Les

I thought the P14 was fitted to the 2 seaters only
or did they see fitment on the very very early +2?
My '70 model has P16B fitted.
The metric caliper was not used until '72 or so?
Cheers,
Scott

Gidday Scott,
No 16's on +2s.
What was the original question on this topic ? Beats me.
See ya, Les