[modern] Self-Leveling Suspension Conversion Part II - Under the Hood

["Lokensgard" <dlokensgard@earthlink.net>]

Hi All,

I replaced the rear shocks (self-leveling) with the standard Boge shocks and
taller springs a few weeks ago with very nice results using a kit from
Coventry West.  Last weekend I finished the job (the "suspension downgrade",
right Pete?) by removing the remainder of the high pressure hydraulic system
from under the hood. On '90 and later models, all this system does is drive
the rear suspension, not the brakes, so it is just leaky noisy power-robbing
dead weight if the rear suspension has been converted.

I had already removed the oil pipes in the rear and the long pipe that goes
from the valve body to the rear. To do the rest of the job I first bought a
blanking plate and three bolts to hold it on, as well as the hose that
carries oil from the reservoir directly to the power steering pump in the
non-SLS-equipped models. These items are standard Jag parts.

I put a long funnel next to the PS pump and oriented the end to empty into a
pan under the car, pulled off the hose from the pump and let it drain into
the funnel.  Also drained some coolant and removed the top radiator hose to
get good access to the pump on the front of the engine. Then the other ends
of the Y-hose with filter were disconnected from the reservoir and the feed
side of the HP pump, and the hose was removed. By the way, this filter
should be replaced periodically if you have the hydraulic system (all 86 -
89 models and '90 and later with SLS), it's not in any of the maintenance
schedules but it protects the HP pump and the valve body internals by
removing debris from the oil which is continuously circulated through it.
The valves will fail open or closed, or the little screens they have on them
will clog, if they get contaminated with particles from the inside of the
rubber hoses. One of the clamps that positions the Y-hose also locates the
coil, so that bolt has to be reinstalled.

The high pressure hose was removed next, together with the bracket that
supports it from the valve body bracket. I cut an inconspicuous slot in the
bracket where it clamps the HP hose and opened it up to remove the high
pressure hose, then later closed the gap in a vise and  reinstalled it since
it supports an AC hose on my car.

Next the two nuts that hold the valve body in place were removed, and the
exit hose that leads back to the reservoir was removed.  In each case when
removing hoses from the plastic reservoir tank I cut a slot in the hose and
gently twisted it off rather than simply tugging, since the hose nipples
tend to break very easily and the tank is $$$$$. The electrical connector to
the valve body was disconnected and tied to the wiring harness, and the
valve body was removed.  I reinstalled the nuts flush on the ends of the
valve body mounting bolts to avoid losing them and to avoid having two sharp
bolt ends exposed.

The three bolts that hold the pump onto the front of the timing cover came
off easily with an open-end wrench (no room for a socket with the fan in the
way), and the pump was removed.  There's a drive plate from between the pump
and the drive flange on the engine that falls onto the floor at this point.
In the space under the pump is a flange with drive tabs that engage the
drive plate, this flange is held onto the live intermediate shaft with a
bolt.  This should NOT be removed. There is an oil seal underneath it, so
this area should be dry and free of oil. If it's not, then I guess you would
need to take the drive flange off and fix the seal. A hint of this problem
would be an oil-soaked timing cover below this pump. Anyway, the next step
is just to mount the blanking plate with the three new screws. There's no
need for any sealant, in fact there's a drain slot at the bottom of this
triangular hole so you can't seal it even if you try.  I used a little
locktite on the screws since if they came loose they might hit the fan.

Finally, I installed the new feed hose from the reservoir to the PS pump and
capped off the extra nipple from the reservoir (used to be the return from
the valve body) with a little fuel injection hose and an old stripped bolt
(from an upper shock mount - one of these is stripped on all XJ40s).

Cleaned everything up, refit the radiator hose and replaced the coolant,
topped up with HSMO and all done. I guess you could use ATF or PS fluid in
the system after this, but I didn't want to mess with it and there's nothing
left to leak much anyway.  If the PS pump or hoses go in the future, I might
try ATF as Greg from CW suggested, it's a lot cheaper than HSMO.

When I started the car, there was a slight whine that increased with engine
speed and went away in a few minutes of driving - I think this might have
been the intermediate shaft, chain or tensioner getting used to running in a
new position after the load of the HP pump was removed.

Now I can see the coil and the ignition amp, it looks much cleaner in there!
I saved all the parts in case some future owner wants to put the car back
into original condition.

Dave Lokensgard
'90 Vanden Plas Majestic (DAVZCAT)
'55 XK140 OTS
Poway, California