993 "big red" brake system plumbing question

[cgfen]

Warning, fairly long and technical, but i could use your help.


Specifically my question / confusion relates to the hydraulic pump and pressure reservoir present on Turbos and 4S chassis.
First some data, then the question.
I typically flush the “entire system” at least once a year.
All was well until I started alternating ATE blue / gold.
I can never flush out all the blue and end up with gold fluid in the fender mounted reservoir despite;
• Sucking out as much fluid from the fender mounted reservoir as possible.
• Purging the lines with up to 2L of new gold fluid.
• Clearly seeing only gold come out all 8 bleeders
This time I actually had gold in the fender mounted reservoir and out all the bleeders until I turned the key on and allowed the hydraulic pump to run.
Then the fender mounted reservoir fluid slowly turned blue the longer the pump ran.
I find it hard to believe that the pump is mixing fluid between the pressure reservoir and the fender mounted reservoir, but ???????????
My question is, How can I purge the system and ensure the hydraulic reservoir has new fluid exchange also?
I know there is a bleeder on the pressure reservoir also, and I did drain ~ 50ml from it before fluid flow stopped. Initially the fluid from the pressure reservoir was milky / airy before transitioning to clear blue air-free fluid.
Second question. Is there a 2nd connection from the pump / pressure reservoir to the fender mounted reservoir? Something that would allow mixing?

Thanks for your help.

Craig

[Bill Verburg]

The procedure is outlined on pg 47-19 and 47-20 of the shop manual

If you don't have a manual PM me and i'll send a copy

there will be some residual fluid in the abs pump which you will need a hammer or PS2 to flush out

[cgfen]

Originally Posted by Bill Verburg

The procedure is outlined on pg 47-19 and 47-20 of the shop manual

If you don't have a manual PM me and i'll send a copy

there will be some residual fluid in the abs pump which you will need a hammer or PS2 to flush out

Thanks Bill, i'll check my home computer.
Fairly certain i have shop manual PDF there.

Craig

[cgfen]

Originally Posted by Bill Verburg

The procedure is outlined on pg 47-19 and 47-20 of the shop manual

If you don't have a manual PM me and i'll send a copy

there will be some residual fluid in the abs pump which you will need a hammer or PS2 to flush out

Spot on Bill, thanks for taking the time to point me in the right direction.

cheers

Craig