simonbuk wrote:I did wonder about doing it this way !!
I also wondered why the fluid needs changing every 3rd service ? Does it absorb water like brake fluid ?
In the Service Manual it's actually a C service item which is every 5th service @ 30,000 mile intervals but is also shown as Maximum Time Period of 24 months, which will come sooner unless you do 15k miles per year.
The Manual says "Nippon Oils 'Besco A.T.F. Dexron' ; Lotus Part No A100E6088V but you'll have trouble finding that. Dexron is trade name used by G.M. for their Automatic Transmission Fluids (A.T.F.) and they have evolved over the years...
history here ....
https://en.wikipedia.org/wiki/DEXRONYou'll see on that link that Dexron IID, introduced 1975, was hygroscopic and IIE (which I know was introduced 1991) had reduced hygroscopicity. So yes, the service schedule allows for replacing because of hygroscopy.
Dexron III was introduced in 1995 as backwards compatible and remained until 2005 when it was replaced by Dextron VI.
I changed my alternator last year which required removing the PS Reservoir so I needed PS fluid and looked all round the internet trying to sort out what to get. Was passing Underwoods of Sudbury, my local Vauxhall Dealer, and called in and asked about "Nippon Oils 'Besco A.T.F. Dexron" and the Service Manager gave me a very detailed history of Dexron Oils, better than Wikipedia, and said Dexron VI was suitable replacement, has greatly reduced hygroscopicity and doesn't need changing so often in Vauxhall cars.
There is a comment in the Service Manual (HC.2 Page 5) that allowing air to enter a running pump can cause damage so air locks in hoses are to be avoided. As the aim of maintenance is to improve the life of components I'm with Simon_P on the simple 'drain & refill the reservoir' procedure, though I use a vacuum pump. How many times you repeat it may depend on how often you plan to do it. Not a lot of people know that ...( Michael Caine voice)... when you change the engine oil and filter (3.5l) you are still leaving 1.25l of old oil in the cooler and pipework so it's only a partial renewal each time. If it works for the engine , why not the PAS?