ASTRA GTE Mk 1 POWER STEERING CONVERSION

IAN HOWES – SEPTEMBER 2002

1 Which one will fit?

The only one I can say for definite that fits is the rack and pump from a pre 1985 MkII Cavalier Cdi. The pre 1985 model is the one that has the brake servo on the passenger side like the MkI Astra GTE in standard form. One important point to remember is that you will need the flexible coupling from the Cavalier Cdi as the rack has a splined pinion unlike the MkI Astra which has two flats.

The manufacturer is ZF

The numbers on the aluminium identification plate at the drivers end are:

7836 974 102
034954 0584

The numbers on the casting are 7836 107

(See Fig 4)

Before I fitted it I made some measurements of the geometry, which may help to identify if other racks are likely to fit. This basically confirms that the rack will mount in position on the bulkhead, that the pinion shaft is the correct length and that it aligns with the existing hole through the bulkhead.

Fig 1

The other dimensions I checked were;

Distance between mounting bracket centers = 600mm

Distance from fixed mounting to pinion centerline = 90mm

If all of the above are correct you only have to check if you have sufficient clearance either side of the mountings to accept the length of the rack. If you do then the rack will bolt in place.

2 Removing Cavalier Rack

If you’re not lucky enough to be handed one ready to fit then you will have to remove it. I only mention this because of the problems I had trying to remove my one.

Separate the two fluid pipes at the junctions on the passenger side near the brake master cylinder and plug them to stop any dirt getting in. The flexible pipes from the pump have two brackets supporting them and the one by the engine mounting is a bastard to get to so I left it. Slacken the belt and remove the 3 bolts holding the pump to the front of the block.

The rack was a bit more difficult with the pipework attached but it will come out through the wheel arch if you bend the metal a bit with mole grips to give extra room. It would be easier with two people to help feed the pipes through without them snagging.

I was beginning to panic when I couldn’t get it out through the wheel arch before I remembered I was in a scrap yard and could just bend metal out of the way.

Don’t forget the flexible coupling from the steering column.

3 Fitting the Rack

Remove the existing rack, which is just a case of disconnecting the tie rods, unbolting it and pulling it out through the drivers wheel arch through the inner wing. Remove the coupling from the steering column.

Enlarge the hole through the bulkhead to allow the pinion body to pass through. The picture below shows the rack fitted so you should get a good idea of the final size from the bulkhead pressing detail. I'd expect the next person to make a far tidier job of it than I have. I found this easier from the inside unless you’ve already got the engine out of course.

Fig 2 Fig 3

Despite what Mr Haynes usually says, fitting is not the reverse of removal as I didn’t want to get the mole grips on my inner wing. I did try fitting it through the wheel arch but even with the lower ball joint disconnected and the strut pushed forward it wasn’t going to go through. You need to disconnect the fuel pipes from the injector pipe and feed it down and under from the drivers side. A bit fiddly for one person but it does go.

(I can only speak for 1.8 8V engine though).

Fig 4

I used the GTE tie rods. The front track of the Cavalier is identical so these should work also unless the offset in the tie rod is different.

There seems to be less space behind the rack gaiters for the rubber fuel pipes to pass so I’m thinking of having a short section of metal pipe to run behind it to avoid excessive rubbing of either the gaiter or the fuel pipes.

4 Fitting the pump

All standard MkI GTE’s have a double pulley on the crankshaft to accept the power steering pump drive belt.

The pump bolts onto the front of the block on all standard GTE engines. As these holes have probably never been used they will be rusty and should be re-tapped before fitting the pump. These threads are M10 x 1.5.

Fig 5 Fig 6

Feed the pipes through to meet those on the rack and reconnect. Fit the brackets to the engine/gearbox casing. I didn’t fit the engine mounting bracket as I didn’t have one but use cable ties if you need to.

Fill up with fluid (which isn’t easy access) and you’re there.

I’ve since looked at later cavalier CDi racks and although the casting numbers are different I can’t see any obvious reason why they won’t fit.