Dunlop Caliper Pot Diameter(s) 2-1/8 and/or 2-1/4?

[Cardinal Grammeter]

I have notes that only the 1969 311 had the 2-1/4 pots.

 

Is this correct?

 

My problem is that the online parts list for the 311 shows the same caliper parts for all years.

 

Then where can I get affordable seal kits?

 

Thanks

Tom

[ppeters914]

Roadster calipers the same for all years '66-'70.

 

What notes you looking at that say different?

[Cardinal Grammeter]

All I have is some word of mouth that the 1969 311 used the Dunlop/Sumotomo 2-1/4 inch pots.

 

I have seen many Datsun 311 Dunlop/Sumitomo 2-1/8" for sale on eBay.

 

Since the online 311 parts catalog shows only one set of parts, there can't be both sizes used on the 311.

 

I need someone familiar with roadster calipers to tell me what size(s) they used and what years if applicable.

 

I'm trying to find 2-1/4" seal kits. 

 

It is amazing how little information there is out there regarding the 2-1/4" Dunlop pots.

 

NOTE:  There is a lot of confusion with the Girling 2-1/4" pots which are completely different, being of "Girling design" - the seal residing in the pot, not the piston.

[Cardinal Grammeter]

I just got a reply back from a guy on eBay selling seal kits and he says the 311 never had the 2-1/4" bore pots.

 

I believe this is true and that the information that I was told about the existence of 2-1/4ers is bogus.

 

I did find that the ONLY place they do seem to be used is in the big, heavy Jaguar MK X in the latter 3.8 models - the early 3.8's used the 2-1/8s.  I think 61-64 is the year of the big bores.

 

The big bore give about 12% more braking for a given pedal effort which is always a good thing and I have always thought a good idea for any of the Dunlop fixed caliper cars which include Studebaker, Ferrari, Lancia, Datsun, Toyota Crown and Corona, and ???

 

Still, I'd like to get an informed confirmation on this conclusion I now believe in.

 

Thanks

Tom

[exit64]

Last time I bought parts for this was direct from Nissan.  You can still get NOS caliper pucks too from Nissan.  Part numbers are in the techwiki on 311s.org.

[Cardinal Grammeter]

I actually found an old receipt in 2002 for 41120-73425 seal kits for $25 from Rod's Discount Datsun Parts.  (I believe I got 2-1/8 seal kits from him because the price was good.)

 

Just talked to him right now and yes, Datsun never used the 2-1/4" bore pots.  (Turns out they were used on the Jag MK9, some Ferrari's, and Toyota Coronas and Crowns.)