[TR] TR4 vs 4A clutch piping

Allen Hess allenhess at mgcarclub.com
Fri May 7 17:34:16 MDT 2010


I have a 4 and didn't know there were differences, but the pressure  
plate on the TR4 is the coil spring type and the TR4A - 6 uses the  
diaphragm spring. Maybe that figures into the change.

On May 7, 2010, at 2:00 PM, triumphs-request at autox.team.net wrote:
> From: Peter Caldwell <peter at nosimport.com>
> Date: May 7, 2010 10:38:55 AM EDT
> To: triumphs at autox.team.net
> Subject: [TR] TR4 vs 4A clutch piping
>
>
> Cognescenti listerati,
>
> 	I have a customer who is needing to re-plumb his clutch  
> hydraulics. His car is a TR4, as we've determined through the  
> years. It seems that what is on the car, though is 4A stuff. (lots  
> of it)
>
> 	Using various original TR manuals, and Moss, et. al., it seems that;
>
> 	 4s used 3/16 tubing and a rubber flex hose at the slave. The  
> fittings would have been a 3/8-24 male single(bubble) flare into  
> the master, a length of 3/16 tube, a 3/8-24 female nut single  
> flare, rubber hose with a long 3/8-24 male fitting to accommodate a  
> nut for a bracket. rubber hose (8") with a 3/8-24 straight fitting  
> requiring a copper gasket at the slave.
>
> Whereas
> 	4As used 1/4" tubing and a stiffer kind of flex tubing a la 6s at  
> the slave.
>
> 	Both use the same master cylinders, and hence bore diameters.
>
> 	My questions are:  1) am I correct in the above?
> 			
> 			2) In other cars, when the line diameter changes from 3/16 to  
> 1/4 there is a concurrent change in bore diameters of either the  
> master, or the slave, or both.   Why not with the 4A, and are there  
> advantages of 1 plumbing scheme over the other.
>
> 	We are thinking that while this car has many parts of both 4s and  
> 4As, that it would be best to make it as much a true 4 as possible,  
> unless there is a compelling reason to switch to 4A clutch piping.	 
> Pedal feel?


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