Hyd. pump rebuild experience (long).

["Arun Rao" <rao@quattro>]

	Folks,

	I resealed the leaky hydraulic pump on my '91 200Q (*way* too
	early, at 54K, I think) last weekend, and here's an outline of
	the procedure. Hopefully it will be of use to some fellow lister.

	Thanks to all the listers who helped in various ways: please
	add to or correct the following if I've missed anything.

	Tools:

	- 13, 15, 17 and 19 mm sockets and open-end wrenches.
	- U-joint extension is very helpful but not essential.
	- Set of long handled metric Allen keys or hex bit sockets.
	- Bench vise and jaw protectors or a couple of pieces of wood.
	- Hand-operated siphon (cheap plastic thingy) and turkey baster.
	- 3/4" drag-link socket for 1/2" drive, available from
	  professional tools suppliers (Snap-On, MacTools)
	- 1/2" hand impact drive (any h/w store -- mine from Home Depot).
	- Hammer.

	Parts:

	- O-ring repair kit (about $20.00 from Carlsen, but I paid
	more to Blaufergnuegen instead :-()
	- 2 litres of "Ol fur zentralhydraulik ..", CHF 7.1 (*not* CHF
	11 unless you're already using it).

	Procedure:

	1. Drain hydraulic reservoir with siphon.

	2. Disconnect hoses connected with three banjo nuts to
	the pump (all three are different sizes). The front-most
	hose is also anchored to the rear of the pump with two
	bolts. At this point you can move all but the front-most
	hose out of the way (on the 3B engine .. disregard for
	older I-5's).

	3. Drain as much oil from the pump as possible using the
	baster (to minimize the amount of oil on your garage floor).

	4. Loosen top mounting bolt (about which the pump swings), then
	the hard-to-reach nut on the tensioning bracket (I used two
	extensions on my drive), and then the main tension adjusting
	bolt (U-joint extension really useful for this -- the axis
	is very close to the radiator housing). Remove the tension adjusting
	bolt and then the threaded fitting into which it goes.

	5. Slip belt off pulley, and swing pump enough to work the front
	hose end out from under the pump mounting collar. (Applies only
	to 3B engine).

	6. Remove the last mounting bolt and lift pump out (rotate clockwise
	and lift out vertically on the 3B).

	7. Clamp the pulley in the vise (use protectors) and remove the pulley
	bolts. Then remove the four bolts (two Allen head, two regular) holding
	the mounting collar to the pump.

	8. Clamp the pump in the vise and remove the two long Allen head bolts
	that hold the two halves of the pump together. They're torqued down
	quite tight, but come out easily once they break loose.

	9. Replace the 6 (?) little O-rings and the big middle one. There were
	little black pieces of crud in the O-ring channels in mine: I swabbed
it
	clean with Q-tips. The O-rings must be coated with mineral oil before
	installation.

	10. Remove the two check-valves (hex key, pretty tight) and replace the
	O-rings.

	11. Bolt the two halves back together, and prepare to do the cap seals.

	12. Clamp the drag-link socket in the vise and file down the corners by
	1 mm on each side so that it fits the slot on the cap screws
	-- I tapered mine a little to match the shape of the slot.
	(This is actually pretty easy to do -- I had the impression that
	sockets were made of sterner stuff).

	13. Clamp the pump in the vise, and do the cap seals one by one. The
	pump's very odd-shaped, so be careful when clamping it -- I had mine
	work loose a couple of times. (It would not be funny if that pump
	were to fall on your foot -- though you'd save your pump!). To remove
	the cap screw, use the impact driver with your custom drag link socket.
	For those of you who haven't used one before, you twist it as far as
	it will go counterclockwise and hit it with a hammer while doing so.
	You have to hit pretty hard, but it comes out by hand once it's loose.

	14. Fit mounting collar and pulley, and then Mount pump back in the
car,
	but connect the hoses only after filling the pump with oil and
	rotating the pulley until oil comes out of the farthest port.

	15. While reconnecting the front hose, it helps if you screw in the
rear
	mounting bolts loosely first.

	16. On the 3B, there are two little metal fingers on which
	the pump drive belt can easily snag while tensioning the belt.
	Look carefully to make the belt isn't snagging before you
	start the engine (I shredded my belt by not doing so ...
	luckily the belt needed replacement anyway).

	17. Refill reservoir with fluid, and start the car. Check for leaks,
	and rotate the wheel from lock to lock quickly several times to bleed.
	Make sure the reservoir stays topped up, and bleed until the air
	bubbles stop.

	That should do it. I didn't do the shaft seal, but any shop with
	a hydraulic press should be able to do it for you.

	The seals were in pretty bad shape on my car -- hard, and breaking up.
	I suspect that this was because some quick-lube place topped the
	reservoir up with the synthetic variant (CHF 11, green can w/ red cap)
	(lots of places don't know any better, as I found out the hard way).

	-Arun

--
Arun Rao
Pixar Animation Studios
Pt. Richmond, CA 94804
(510) 215-3526