Alex Lowe Posted August 14, 2019 Report Share Posted August 14, 2019 Hi all im sure this has been asked before but how do I tell whether i have imperial or metric calipers fitted i have a late Mk3 1974 registered car which I believe has type 16PB fitted Also where is a good supplier for replacement as mine are rusted stuck Link to comment Share on other sites More sharing options...
Colin Lindsay Posted August 14, 2019 Report Share Posted August 14, 2019 It will say 16PB on it - look around the bracket where the securing bolt goes through to the vertical link, it will be close to the bolt head. Link to comment Share on other sites More sharing options...
Alex Lowe Posted August 14, 2019 Author Report Share Posted August 14, 2019 Ok iv found that but how do i tell if it is the metric version or imperial? Link to comment Share on other sites More sharing options...
johny Posted August 14, 2019 Report Share Posted August 14, 2019 The Rimmers site says the metric type were fitted from chassis numbers KE12390 and KF12391. Of course yours could have been changed but I believe the bleed nipples are different with the metric type logically needing a metric spanner so the usual 7/16" spanner doesnt fit. Link to comment Share on other sites More sharing options...
Alex Lowe Posted August 14, 2019 Author Report Share Posted August 14, 2019 Hmmmm mine may have possibly been changed as I used a 7/16 when i attempted to bleed the system is there any difference if in which i choose as I am fitting new copper pipes as well Link to comment Share on other sites More sharing options...
johny Posted August 14, 2019 Report Share Posted August 14, 2019 whats your chassis number? Link to comment Share on other sites More sharing options...
daverclasper Posted August 14, 2019 Report Share Posted August 14, 2019 Off the top of my head, I think Gt6/Vit calipers are, 16P and 16 PB imperial, then the later caliper metric, though can't remember the reference. Rimmers site is good for ID ing parts to different models. Dave Link to comment Share on other sites More sharing options...
Alex Lowe Posted August 14, 2019 Author Report Share Posted August 14, 2019 KE23834 is a late production car i believe Link to comment Share on other sites More sharing options...
johny Posted August 14, 2019 Report Share Posted August 14, 2019 yes that should be metric and I think the caliper fixings are different so not easily interchangeable. Measuring the distance between the caliper fixing bolt centres is the definitive way to tell and Ill measure it on my imperial items.... Link to comment Share on other sites More sharing options...
dougbgt6 Posted August 14, 2019 Report Share Posted August 14, 2019 Also note that the brake pads are metric or imperial! Doug Link to comment Share on other sites More sharing options...
johny Posted August 14, 2019 Report Share Posted August 14, 2019 Mine measure approx 90mm between centres Link to comment Share on other sites More sharing options...
Nick Jones Posted August 14, 2019 Report Share Posted August 14, 2019 16PBs and M16 look very similar. I think the diameter of the pad pins is the easy give away. The M16 ones are small (4mm ish) and the others are larger (6mm / 1/4" ish IIRC) Link to comment Share on other sites More sharing options...
Alex Lowe Posted August 14, 2019 Author Report Share Posted August 14, 2019 yeah im confused as the mountings are approx 90mm between centres and the old calipers defiantly say 16pb but it is a late production car which i though should be metric. is that pad pins diameter measurements? Link to comment Share on other sites More sharing options...
johny Posted August 14, 2019 Report Share Posted August 14, 2019 yes and you can see the difference clearly on the Rimmers site which has both imperial and metric calipers for the GT6 Link to comment Share on other sites More sharing options...
KevinR Posted August 14, 2019 Report Share Posted August 14, 2019 One of the differences is the diameter of the mounting holes. The Metric calipers require a stepped shank bolt, part number 158713, where the Imperial calipers require a straight shank bolt, part number 132439. If you remove the bolt and it has a stepped shank then you have Metric calipers. If the bolt has a straight shank (and is not a loose fit in the caliper body) then you have an imperial caliper. The bolts to mount the Metric calipers are about 3 times the price of the ones for the imperial calipers, and yes, I've seen cheapskates use straight shank bolts on Metric calipers - the effect on braking is "interesting." Also, the threads for the pipe fittings are Metric Or Imperial - and it is very easy to fit the wrong thread type and get a serious leak ! Just because the chassis number says the calipers are Metric or Imperial does not mean they actually are - never underestimate the ingenuity of a previous owner. With the correct fittings 16P, 16PB(I) and 16PB(M) calipers will fit - even mix and match on different sides of the car. 1 1 Link to comment Share on other sites More sharing options...
Colin Lindsay Posted August 14, 2019 Report Share Posted August 14, 2019 1 minute ago, KevinR said: One of the differences is the diameter of the mounting holes. The Metric calipers require a stepped shank bolt, part number 158713, where the Imperial calipers require a straight shank bolt, part number 132439. If you remove the bolt and it has a stepped shank then you have Metric calipers. If the bolt has a straight shank (and is not a loose fit in the caliper body) then you have an imperial caliper. Another excellent piece of info for me to salt away for future use! Link to comment Share on other sites More sharing options...
johny Posted August 14, 2019 Report Share Posted August 14, 2019 Kevin do you know if the spacing of the caliper fixing bolts is different? Link to comment Share on other sites More sharing options...
Clive Posted August 14, 2019 Report Share Posted August 14, 2019 Spacing is the same across all the 16 series callipers. As Kevin points out, the differences are holes and threads... I would not trust pad pin size, somebody could drill a metric calliper to accept the earlier pin. Worth sending the callipers away to get them reconditioned. Much better than the new ones on the market (Nick has done a comprehensive write up of the problems with the brand new callipers) Link to comment Share on other sites More sharing options...
johny Posted August 14, 2019 Report Share Posted August 14, 2019 Thanks. It was just that Im sure I read somewhere that Ford 16P calipers (metric?) can be fitted on our cars (for example to allow vented discs) but they have a different fixing bolt spacing.... Link to comment Share on other sites More sharing options...
KevinR Posted August 14, 2019 Report Share Posted August 14, 2019 The GT6 caliper (all types) has a 3 1/2" bold spacing. The M16 calipers fitted to the late Ford Cortina GT had a 3 1/4" bolt spacing. The bolt spacing on the Spitfire and Herald is 3 1/4" for the type 14 and type 12 calipers. Therefore it should be possible to fit M16 calipers onto a Spitfire or Herald - with an appropriate modification to get the disc offset and thickness correct. 1 1 Link to comment Share on other sites More sharing options...
Alex Lowe Posted August 14, 2019 Author Report Share Posted August 14, 2019 hmmm so it is possible that someone in the past may have fitted imperial calipers to my car which should have metric as thats what i feel must have happened if so should I revert back to the metric type? Link to comment Share on other sites More sharing options...
KevinR Posted August 14, 2019 Report Share Posted August 14, 2019 As I said, never underestimate the ingenuity of a previous owner. Not strictly necessary to revert to the "correct" calipers, all 3 types are effective as each other - but the dust sealing of the 16P pistons is not as good as the 16PB. Link to comment Share on other sites More sharing options...
Clive Posted August 14, 2019 Report Share Posted August 14, 2019 I have metric callipers. They have a substantial advantage in that they use the readily available pads shared with escorts/Capri etc, and you can get the excellent mintex 1144 pad material very easily (or many other compounds) Link to comment Share on other sites More sharing options...
Alex Lowe Posted August 14, 2019 Author Report Share Posted August 14, 2019 hmmmm im leaning towards going for some metrics then seems like the best option as i need new bolts and pins anyway and have new pipes for ether imperial or metric Link to comment Share on other sites More sharing options...
dave.vitesse Posted August 16, 2019 Report Share Posted August 16, 2019 The other difference with the pads is the metric type have pad material right to the edge of the metal backing plate. The metric type is on the right. Dave 1 Link to comment Share on other sites More sharing options...
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