I spent the entire day working on the ABS pump. The nut on top is not exposed and is covered by a push on cap that has zero grip, so I had to drill it to pop it off (12mm hex 1/2" drive). I tried my best but had 2 failures, The first was a main nut on the side that I simply could not get off, ( 6 point 24mm) maybe I will try heat but I felt the unit a bit fragile (orings etc.) for heat but I may disreguard that tommorow. The other is that I was unable to get the solenoids cleaned well enough. I bought an ultrasonic cleaner but I did not get aggressive enough with the solution, I used krud kutter. I may switch to gasoline tommorow (outside, in a water bath, in another container in the ultrasonic). The ABS unit had 35 years of brake fluid crud in it and the solenoids showed signs of being black but did in fact work when power was applied (positive yellow negative black). When I re assembled it some air would go through but when I tried it a second time it was blocked and then it would just change. I just checked again and none of the ports flow correctly, it is as if I loosened junk in the solenoids and it just moved around. I tried an experiment to see what would melt the old crub. In the end nothing really did, and the passages are so small that any cleaner sprayed into it would have zero velocity once it got there. The test you see soaked for 30 minutes and the unmarked container below that image is brake cleaner which did nothing to the crud but move it around. Cleaning, by spraying chemicals into the ABS unit, in my opinion, is useless.
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Interesting

Thanks for the pics and description.

Good luck with this.

 

When I see these posts on how gunked up these units can get and how hard they are to work on it is easy to see why rebuilders charge 900 bucks to completely clean, replace all o-rings and seals and test and warranty. Dan