Replacing BX Steering Pinion Valve by Oscar Franklin

How to change a pinion valve in situ

Get the engine bay steam-cleaned- it will make this job a lot cleaner and easier, and cleanliness is a necessity when working on the hydraulic system.

First job is release the driver's side road-wheel nuts. When the car is on axle stands, remove the wheel.

Then drop the exhaust. Put the car up on axle stands front and rear, and get as much height as possible. Make sure that it is absolutely secure - give it a good shake to see that it doesn't topple over. You may want to put jacks under the two rear side jacking points too as an extra security measure. Remember that there will be a lot of tugging and shoving - the car should be absolutely stable.

Put the suspension in "Low" and release the pressure release screw on the front of the FDV by ¼ turn with a 12 mm spanner.

At the engine end, undo the exhaust from the manifold. You'll need a 10mm socket and the longest drive you can find to do this. If you have small arms, you may be able to get close enough with a normal drive. Retain the cup washer, spring and fibre washer that are part of the fitting. Remember the order they go back on to the bolt - fibre washer, then spring, then cup washer, concave side upwards. Make sure the exhaust doesn't damage the hydraulic pipes in the vicinity when it comes down.

Once the exhaust is free of the manifold, undo the rubber hangers. There are three. Two are easy, one requires a sort of lift and turn. A bit of silicon spray will make things slightly easier.

Once the exhaust is free, take the opportunity to check it for damage, holes etc and replace any sections that need replacing.

Undo the handbrake cable from the lever on the caliper, and take off the two nuts at the end of the cable. Feed it back through the first guide.

Back under the engine. Take the handbrake cable back through the next two guides and tuck it up out of the way behind your head. This will give you more room.

Remove the heat shield, the bent piece of tin between the pinion valve and the exhaust pipe. This is held on with one 8mm nut and bolt and a spring in the shape of a coat hanger. The heat shield is not an optional extra - it will need to be replaced or your pinion valve will fail.

Working inside the car now. Remove the trim panel on the front of the steering wheel with a sharp tug, to expose the steering wheel nut. Take the nut off with a 22mm socket and retrieve the washer underneath. Remove the steering wheel by tugging upwards in a firm manner, holding both side of the wheel.

Behind where the steering wheel was, you will see two tiny torx head screws, holding the steering wheel shroud. These should be removed with a 1mm allen key or correct torx drive. Underneath the shroud, there are 4 size 20 torx screws. Remove these with the correct torx drive or a 3mm allen key. Remove the shroud and retain the pieces of trim from around the indicator and headlights stalks. You'll need to disconnect the "lights on" warning beeper and the dash lights dimmer switch.

Drop the steering wheel column by undoing the 4 13mm nuts that secure it to the bracket. Unclip the wiring connections for headlights etc. - these pull off. Leave the ignition wiring in place.

You've now got access to the steering column coupling which is undone with a 13mm socket and spanner. Disconnect the steering coupling and the steering column with a sharp tug.

Back underneath the car. Undo the allen bolt securing the hardy disk (rubber disk attached to the steering coupling) to the pinion valve with a 6mm allen key and 12mm spanner. Pull the coupling back inside the car. Examine the rubber disk for cracks by flexing it. If it is cracking, new couplings are available for about £10.

Now working on the pinion valve. With the wheels in the straight-ahead direction, scribe a datum mark showing the relative position of the pinion valve spindle and the pinion valve body. This is important, as otherwise there is a risk of refitting the valve in a position that doesn't correspond to the rack's position.

Now look underneath the steering rack, directly below the pinion valve. There is a lozenge-shaped plate secure with 2 13mm bolts. This is a tensioning device which keeps the rack in close contact with the pinion. Undo the bolts in parallel, as the spring inside is very powerful. As the bolts become loose, be ready for the plate and bolts to fly off under the pressure of the spring inside. Retain the spring and the tensioner - a black plastic hollow cylinder that is a snug fit inside the aperture. The spring fits inside this tensioner. Be aware that there is a narrow o-ring between the lozenge-shaped plate and the rack - make sure that this is retained and replaced when refitting, or LHM will leak from the plate.

Back onto the pinion valve. Undo the two pipes that feed the ram from the pinion valve with a 12mm spanner. Remember which one goes where, although it is difficult to fit them into the wrong holes.

Undo the narrow, high-pressure feed line that goes into the right-hand side of the pinion valve as you are looking at it from below. This needs either a 9mm spanner, if you have one, or a 3/8 spanner if you don't. The low pressure return is undone with a 12mm spanner. Space here is extremely limited and you will find yourself working a ¼ turn at a time. Be patient. When they are completely undone, you may need to pull them out of their holes slightly.

Once these two pipes are undone, undo the 2 cheesehead bolts that secure the pinion valve to the steering rack with a 6mm allen key.

Once these bolts are undone, the pinion valve will pull out.

Refitting is the reverse of removal, except for a few points:
- You'll need to fit new seals to the high pressure feed and low pressure return. The seals that GSF supply are about 1mm too long which makes locating the pipes in the pinion valve extremely difficult. Cut this 1mm off.
- locating the high-pressure feed and low pressure return in the pinion valve is still extremely difficult, even with truncated seals. It will be slightly easier if the pinion valve has not been bolted to the steering rack body yet. Don't tighten the pipes up - just locate them and get them started. It is even easier if you locate and start them before offering the pinion valve up to the steering rack at all. If you do this, make sure that your datum marks line up before refitting the valve.
- This job is made slightly easier again if you uncouple the two pipes from each other. They are held together in a small bracket on the front of the subframe. Removing one from the bracket will give a little more room for manoeuvre. Don't forget to recouple them subsequently.
- Don't forget to retighten the pressure release screw on the FDV!
- You can test the operation of the new pinion valve before refitting the exhaust, so long as you don't take the car for a run. The exhaust won't get hot enough to damage the seals in only a couple of minutes of operation.
- When refitting the exhaust, reprop the car as described above, making sure it is completely stable. Feed the front end of the exhaust pipe over the subframe towards the manifold before mounting the rear end on the rubber hangers. If you don't, then you won't have enough room to clear the subframe subsequently.
- The washer-spring-washer assembly can be fitted by one person using gaffer tape to hold the assembly both together, and in place on the bolt. It's easier with two people. One works from the top of the car, reaching in to the manifold from the passenger side of the engine bay, holding the 10mm head bolt, washer-spring-washer assembly and if possible 10mm nut in place with one hand. The other works from underneath the car with the longest drive they have, to offer up and tighten the nut on the bolt. Use a jack to hold the exhaust pipe in place while all this is going on, as you will find it very difficult to manipulate nuts, drives etc while holding the exhaust pipe up with one hand. The jack need only be hand-tight, not tightened with a lever.
- Don't overtighten the nuts securing the steering column to the bracket, as the bolts, which are welded in, can shear. They won't take anything like the torques used on more modern cars, even though the assembly looks similar.
- When the steering column has been refitted, there may be a knocking sound or vibration or movement in the wheel. This is often because the lower steering column bush has dropped a little. To fix it, undo the coupling and give the steering wheel a sharp tug upwards. This will drive the bush back into position.