MGA Part Numbers

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MGA Part Numbers - AHH5905
Hose -header tank to relief valve

PART NO.  SPL.PAGE  DESCRIPTION                                                                
AHH5903   TC.C.1    29 Relief valve and cage assembly -radiator -(cooling system, Twin Cam)-
    Com.(C)652 also 575, 613, 623, 633, 648
PMZ0308   TC.C.1    30 Screw fixing valve to bracket (2) 
FNZ103    TC.C.1    31 Nut for screw -(relief valve to bracket (2)
LWZ203    TC.C.1    32 Washer for nut (spring) (2) 
AHH5906   TC.C.2    33 Bracket -valve -(cooling system, Twin Cam) Com.(E)652 also 575, 613,
    623, 633, 648 -was ARH1022
HZS0404   TC.C.2    34 Screw -fixing bracket to body (2) 
FNZ104    TC.C.2    35 Nut for screw -(bracket to body (2)
LWZ204    TC.C.2    36 Washer for nut (spring) -bracket to body (2)
AHH5905   TC.C.2    37 Hose -header tank to valve -(relief, cooling system, Twin Cam)-
    Com.(E)652 also 575, 613, 623, 633, 648
AHH5907   TC.C.2    38 Tube -overflow -(relief valve, cooling system, Twin Cam) Com.(E)652,
    also 575, 613, 623, 633, 648)
PCR0607   TC.C.2    39 Clip -overflow tube -(relief valve, cooling system, Twin Cam)-
    Com.(E)652 also 575, 613, 623, 633, 648
PMZ0306   TC.C.2    40 Screw fixing clip to body -header overflow
FNZ103    TC.C.2    41 Nut for screw -clip to body
PWZ103    TC.C.2    42 Washer for nut (plain) -clip to body,
LWZ203    TC.C.2    43 Washer for nut (spring) -clip to body,

MGA Twin Cam pressure relief valve installation

The AHH5905 Hose is item 37 in the drawing illustration. It connects the header tank filler neck to the remote pressure relief valve. As original, this hose would include two zinc plated steel tubular ferrules that serve as hose clips. The ferrules must be installed on the hose before the hose is pushed onto the tube fittings.

It is important that all of the mating parts must have correct as-original dimensions for this to work as a pressure tight push-on fitting.
Measurements:
The pipe stubs from the valve are OD 0.31" or 7.85mm
Plain rings for overflow hose - 2 per car
OD = 5/8" 0.625 or 15.87 mm
ID = 0.55" or 14mm (measured)
It is 5/16" - 0.318" or 8.10 mm wide.
The hose would be 5/16"-ID x 9/16"-OD (1/8" wall thickness)

A gearbox gaiter chrome ring has a bigger ID and is narrower, so no cigar there
Unfortunately these Ferrules came from the factory as part of the hose, so there is no separate part number for the Ferrules.
In a pinch, use any kind of constricting hose clip to secure this hose to be pressure tight.
The drain hose from relief valve to body may not need any clip, as it is free drain with no pressure.