on the ph1 mi what would cause the abs light to come on at speed ,everything else seems fine the light comes on and then goes out after 3 flashes when ignition is switched on as normal but when you hit speeds of 80 -90 it comes on, i also reckon the pump cuts in to much should they start every press of the pedal as this one seems to, i cant recall my last ph1 ever doing it but then its been a long time since i had that.i am thinking wheel sensors but i cleaned and gapped them last week when overhauling brakes to try and eliminate a few things any ideas as i have run out

rust/dirt build-up on the "teeth" on one/all of the CV joints then?

The pump does sound like it is coming on too much. It shouldn't come in every press of the pedal. It might be that bleeding about 5 litres of fluid through might help a bit if it's losing it's pressure through an air bubble. Other problem could be that the master cylinder is leaking some pressure back to the reservoir which gets into the expensive realms of the other thread.

The light coming on definitely sounds like a sensor problem where it is getting conflicting information at a given speed. As Cybernck said, could be rust build up or similar.

have cleaned all the teeth on the cv one thing that did seem odd coming to think of it was they were narrower on one side than the other as in teeth size ,must be more on the one side than the other . did they do different cv joints for the diffferent abs systems .as for the fluid think i will change to dot 5 anyhow as its gonna be used for track

There were two different types of joint. On the late models there is only about 30 teeth and on the early abour 60 (can't remember actual figures)