The hose failure is usually because with old age it rots inside the metal crimp where it fits on the barb.
Hydro bags have not been made in Oz since Dunlop closed their factory (now Birkenhead Point shopping centre).
It is possible to fit new hoses, here's one I prepared earlier by cutting the barb off, tapping a 1/8 BSP thread in there then fitting a 1/8 x 3/8 BSP brass nipple. I then had Pirtek crimp some MPH-06 hose to a 3/8 BSP flare fitting. This hose is rated 500psi and is similar construction & flexibility as the original hose.
Before anybody asks, NO I have had no joy finding any Dunlop Diamond pattern hose as used on these bags 40+ years ago.
Note- the flare fitting at the outer end of a standard hose is 5/8-18 UNF thread. I have been unable to source new ones here, but you could remove and re-use your old ones.
The end fitting on my prototype hose shown is 3/8 BSP, I then made an adaptor to fit it to the rear subframe hydro fitting for testing.
http://www.flickr.com/photos/31275265@N05/8798837447/http://www.flickr.com/photos/31275265@N05/8798852405/Test rig is a dead S rear subby with a bit of SHS tube welded to it. The pump is a Mini clutch MC mounted on a Fiat pedal box.
http://www.flickr.com/photos/31275265@N05/9711727885/http://www.flickr.com/photos/31275265@N05/9714960808/There are other methods of fitting a new hose, however this method allows you to make a hose complete with screwed fitting both ends. easy to fit...
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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.
