[s-cars] P/S flushing procedure

[Kirby Smith]

It takes about 20 seconds (not recently timed) for my light to go out
after the car has sat for a few days.  The bomb is clearly leaking down,
and yours is leaking down faster.  There are two leak points, the check
valve in the bomb, and some part of the power brake assembly.  The
latter can be checked by unscrewing a line at the top of the booster
(see the Bentley for details -- mine didn't seem to be weeping there).
I think in my case it is the bomb check valve.

When I purchased my car the light took a long time, but after cleaning
the screen many times, replacing the filter bolts (could be cleaned by
hand I think) and the high pressure hose with its inaccessible mid-point
filter, the time is now fairly quick, and determined mainly by how long
the pump itself can fill the bomb.  As my bomb takes nearly 40 pumps to
unload, I have been loath to replace it to potentially zero the leakage.

Igor, I think in your case you may have a restriction in the pump flow,
but certainly have a bad check valve.  If the bomb drains down quickly,
the pump is unlikely to fill it instantly.

KBATTPO wrote:
>
> Richard Beels wrote:
> >
> > I have this in my archives...
> >
> >  >>>
> > Date: Fri, 29 Jan 1999 09:11:24
> > To: <quattro at coimbra.ans.net>
> > From: Mike Arman <armanmik at n-jcenter.com>
> > Subject: Subject: Best way to flush mineral oil
> >
> > Weeelllll . . . I *could* say you never need to change the pentosin because
> > the damn stuff leaks out so fast that topping it off insures that you have
> > fresh fluid in the system at ALL times . . . and now as punishment for that
> > wisecrack my "lifetime g'tee" water pump needs another lifetime - R&R
> > Saturday.
> >
> > Also, don't take out the banjo bolts to clean them - there's nothing there
> > - it is just a hollow bolt - and you'll HAVE to replace the crush rings.
> > (One banjo bolt has a filter in it - wire mesh, takes out rocks, etc.)
> >
> > The pentosin reservoir does have a sleeve which can be withdrawn from the
> > top and then cleaned - lots of black glop settles in it - probably rack and
> > bomb $eal$ $elf-de$tructing.
> >
> > I'd drain the reservoir, disconnect the return line at the back of the
> > bomb, clean everything accessable, put it back together, refill and bleed
> > per Bentley: Jack up front of car, engine not running, turn steering wheel
> > lock to lock 2 or 3 times quickly, top off reservoir, start engine, repeat
> > lock to lock, top off reservoir and you're done.
> >
> > You'll need two bottles of Pentosin.
> >
> > Best Regards,
> >
> > Mike Arman
> >  >>>
>
> Thanks Richard for forwarding this to me.
>
> In the UrS it is even much easier than in the 200. I have just done it.
> Perhaps Jimmy would want to archive this procedure.
>
> 1. Lift up the front of the car on jack stands.
> 2. Wrap a plastic bag over the lower intercooler to crossover pipe hose.
> You don't want this sticky fluid cover your beautiful blue Samco hose
> with a messy gunk.
> 3. Undo the 7 mm hose clamp at the rear of the bomb. Surprise, but there
> was no Oetiker clamp on mine. Prolly coz I had the bomb replaced under
> warranty a year ago.
> 4. Pull off the hose and catch the old fluid in a suitable wide
> disposable container. I found that cut in half an empty gallon container
> for the windshield washer fluid serves perfectly well. The fluid will
> drain for a while. And yes it is going to be black and have dark specks
> suspended.
> 5. Now you can undo the P/S reservoir cap. Remove the cylindrical
> plastic insert with the steel mesh and clean it up with the brake or
> carb cleaner.
> 6. Slide the reservoir up off its holder so that the lower return hose
> is not kinked. This will allow you to drain the reservoir completely.
> 7. Spray some brake cleaner into the reservoir to remove the deposits
> from its bottom and let it drain into the container.
> 8. Ask an assistant to turn the steering wheel (the engine is NOT
> running!!!) several times lock to lock to evacuate the remainder of the
> fluid from the steering rack. It will take at least 10 cycles.
> 9. Place the return hose back onto the bomb nipple and tighten up the
> hose clamp.
> 10. Slide the reservoir down back into its holder. Insert back the
> plastic cylinder.
> 11. Pour about 1L of hydraulic fluid into it until the level is at MAX.
> 12. Turn the steering wheel several times lock to lock quickly to bleed
> 13. Start the engine and run it for about 2 minutes. The bubbles will be
> coming out of the reservoir. Keep an eye on the fluid level and DO NOT
> let it run dry or you WILL destroy the P/S pump.
> 14. Shut off the engine. Top off the reservoir to the MAX line.
>
> Now, a few observations.
> 1. With no residual pressure in the sys upon the start up it took the
> pump 40 seconds to extinguish the light! Does my pump work properly? It
> was replaced under warranty about a year ago.
> 2. After the pressure has been built up (the light is out) it took 10
> quick foot stabs to bring the light back on. Is this what you see folks?
> 3. After the engine had been shut down it took 39 pumps for the pedal to
> go hard. At least the bomb is holding the pressure.
> 4. If the car sat on the lot for an hour or two, there is no residual
> pressure and the whole light concert started over again. Is this what
> you see folks?
>
> Igor
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