Showing posts with label replace. Show all posts
Showing posts with label replace. Show all posts

08/11/2011

How To Replace Power Steering Rack On A Porsche 944

THE WHY

My 944 usually only sees action at the weekends and most weeks sits patiently in its parking spot on my road. I remember it had been a particularly wet week and one morning when I left the house I glimpsed an unexpected amount of oil floating on the surface of the water that was laying in the kerb by the side of my car. That evening I had to do a short drive and instantly it became clear that things with the steering were not at all well. As soon as I turned out of my road a resonating groan came from the direction of the engine and was repeated at nearly every other turn until I reached my destination. A quick check in the power steering bottle confirmed it was almost empty and nowhere near as full as it should have been. At first I suspected that a power steering line that had been badly fitted by a previous owner (it was on my list of things to do) was the culprit. However when I had a look in the clear light of day it was coming from completely the opposite side. Having quickly whipped off the undertray it was clear the leak was coming from the rubber bellow at the end of the steering rack.

THE TASK

You will need the following:

32mm Spanner
32mm Socket (optional)
19mm Socket and/or ring spanner
17mm Socket and/or ring spanner
2 x 13mm Socket and/or ring spanner
2 x 10mm Socket and/or ring spanner
Flat bladed screwdriver
Centre Punch (optional)
Small hammer
ATF (Automatic Transmission Fluid) Dexron II
General purpose grease
WD-40 or similar penetrating oil
Oil catch tray

THE HOW TO

(Amateur mechanic job time approx. 2-3 hours)

It is worth pointing out straight away that the power steering rack for right and left-hand drive cars are identical, however the suspension cross-member and the way the power steering rack attaches to the cross-member are different.

Left-hand drive cars have two extra mounting adapters that secure the rack to the crossmember (as shown in the Porsche parts picture below) whereas right-hand drive cars don't, the rack simply bolts straight to the crossmember and no adapters are needed.

Left-hand drive power steering rack (Red arrows show adapter brackets)


Left-hand drive cross member (mounts at 90 degrees on front, no hole for steering gearbox)



Right-hand drive power steering rack (without adapters)


Right-hand drive cross-members (blue arrows show mounts at 45 degrees on front and orange arrow shows hole for steering gearbox)




To make this job as easy as possible raise the front of car as high as you can go, then remove the undertray by undoing the 5 bolts that hold it on. If you are doing this on your own it also helps to remove the front wheels to take the weight off the track rods when you detach them from the rack.

Next step is to confirm you actually that leak is coming from the rack itself, if it is then nine times out of ten you'll see red fluid coming from one or both of the black rubber gators as was the case with one of mine.

Pop the gator off at the end that is attached to the rack and roll it back to expose the 32mm nut that attaches the steering track rod to the rack inside. On the edge of the nut you should notice it has notch that has been tapped; this is to prevent the nut from undoing, thus before you can undo the nut you need to tap back this notch so that it will pass the groove it sits in.


With the nut undone position the track rod so it is not in your way and repeat the procedure for the other side.


Next position an oil catch tray underneath the car and detach the hose at the point where it connects to the power steering coiled oil cooler (shown by blue arrows below) and drain as much power steering fluid as you can. It helps to undo the cap on the power steering bottle so a vacuum isn't created.


With most of the oil drained you can now detach the other hose from the point where it meets the power steering pump (blue arrow below) with a 19mm spanner/socket and catch the remaining oil.


With the hoses removed you are now almost ready to begin detaching the rack itself. At this point if you are following the Haynes or Porsche 944 workshop manual it will tell you to remove the stabiliser bar, this may be necessary for left-hand drive cars but I was able to manoeuvre/wiggle the rack about and remove it on my right-hand drive 944 without doing this and it wasn't too much hassle.

To remove the rack start by undoing the four 13mm bolts that secure it to the cross-member.


Don't undo the bolts completely though as you also need to undo and remove the single 13mm bolt (blue arrow below) that attaches the steering linkage to the rack. Keeping the rack momentarily held by the four steering rack mounting bolts aids its removal. It helps to spray some penetrating oil on the bolt and spline itself as it can be difficult to undo and ease apart. You must remove the bolt completely as there is a grove in the spline that it sits in. With the bolt removed if the linkage won't budge off the spline you can tap a screwdriver into the slot and ease the jaws of the clamp slightly, use more penetrating oil if you have to.


With the linkage detached and the four cross-member bolts now completely removed you can proceed to wiggle/twist and manoeuvre the rack free from the car.


The only thing left for me to do was detach the two steering oil lines from the rack that I had detached from the pump and oil cooler earlier (the large thick one in the picture above and the skinnier one shown by itself in the picture below). You will use these again with new copper washers on the replacement rack.



The replacement rack was a reconditioned part with all new seals and brand new rubber gators that I got from a seller on ebay who specialises in replacement steering racks for all types of cars. The rack arrived within a day or so as a complete unit (you have to send him back the old rack as part of the deal). I also purchased some replacement copper washers for where the steering oil lines attach to the rack and steering pump, I got these from a general auto store for few pennies.

As a side note if you are interested in replacing the seals on the rack yourself check out the tutorial here on Rennbay http://www.rennbay.com/psrsealkitfull.html

You will now need to reconnect the lines to rack with the new copper washers (following the correct torque settings in the Porsche manual).

Next step is manoeuvre the new rack back into position on the car. Use 2 of the 4 mounting bolts to loosely hold it in place whilst you line up steering linkage with the spline (make sure the flat groove on the spline lines up with the bolt hole otherwise the bolt will not tap through). When the linkage is attached you should be able to see clear through the bolt hole and the bolt should just push/tap through with ease. If you're slightly out of alignement even by 1 or 2 notches on the spline the bolt will not got through and you'll need to repeat the whole alignment procedure again. It took me 2-3 attempts to get this right.

Don't worry at this point trying to centre the tracking with the steering wheel in the car as you will do this at the very end when the wheels are back on the car. This is a simply case of pointing the wheels directly ahead and removing and adjusting the steering wheel.

With the linkage attached and bolted to the spline you can do up all four steering rack mounting bolts so the rack is now securely in place.

The next step is to fit the new gators to the track rods. I found the easiest method was first to use a little grease around the openings of the gators and slide a 32mm socket inside side them first.



This helps you easily slide the gators over the wobbly joint on the end of the track rod (you can just see the socket butted up against the wobbly joint pointed out by the orange arrow below)




Slide the gator all the way onto the track rod and onto the rubber bung (shown top left in the photo above).

You are now ready to hook the track rods back up to the rack. Carefully line up the threads on each side and do up the wobbly joints so they are finger tight. Then tighten them with a spanner. It is important that you use a punch or flat bladed screwdriver to tap the locking notch back into place (as shown below by the orange arrow). This prevents your steering coming apart through vibration and is an essential safety feature.


The final step involves putting a light amount of general purpose grease on the steering rack itself before the rubber gators are attached to either end of the rack.

You are now ready to reattach the hoses from the rack to power steering pump and pipe from the power steering oil cooler.



As a precaution I used some plastic cable protector to wrap the pipe to prevent it rubbing on some points on the chassis (shown by orange arrows below).




With all the pipes connected (making sure they are routed correctly and away from any belts or other moving parts, plus clean any old ATF fluid away from any of the pipe joints as this makes it easy to identify new leaks as opposed to phantom ones) you are now ready to fill up the power steering bottle to the level on the dip-stick. Pour in the ATF fluid as slowly as you can as you want to minimise creating bubbles. When the level appears to to remain constant and with the car still raised off the ground start the ignition and allow the engine to run. Keep checking the level in the power steering bottle and top up as necessary. When the level appears to remain static slowly turn the steering wheel completely to the left, top up power steering fluid. Then turn the steering wheel completely to the right, top up power steering fluid. Repeat several times until no change in the fluid level occurs. Turn off the ignition and slide back under the car to check for leaks at all the points where you disconnected/re-connected the power steering hoses, if no red fluid appears to be leaking from anywhere and the fluid level hasn't dropped then it looks like you have done a good job. Before re-attaching the under-tray I took the car for a quick test run, brought it back, checked for leaks and did a small top-up on the fluid and that was that.

If you find that your steering wheel is not centered then make sure the road wheels are facing forward as straight as you can get them by manoeuvring the car. Then pull off the horn button that sits across the centre of the steering wheel. Use a socket with and extension bar to undo the big nut in the centre. Then simply pull off the steering wheel, adjust it to the correct position, reattach the nut and horn button and you are done.


As a final bonus and if your power steering pump needs an overhaul you can find a good tutorial for it below.


Also, here's an overview of the power steering system on a left-hand drive 944 you may find useful too.



--- UPDATE June 2022 ---

So, it's been 11 years since I installed this refurbed rack back in 2011, but today I had to repeat the job again as it had begun leaking fluid on the near-side seal. There were unfortunately no refurbed racks readily available from any of the UK sources I tried, so I've taken a chance and gone for one that's been pulled from a parts car. Installation and removal went exactly the same as in this tutorial. I'll keep the leaking one as a spare that I can send for refurb at a later date.


22/06/2011

How To Remove And Replace Porsche 944 Transmission Drive Axle Seals

THE WHY

If you're experiencing an oil leak coming from the rear of your Porsche 944 then it is probably coming from the transmission/gearbox's oil filling plugs (there are two) or more likely one/both of the drive axle seals (one either side where the drive axle meets the transmission). Other symptoms include harder than usual shifting or transmission whine due to lack of transmission oil. Having replaced the filling plugs for new ones at the last gearbox oil change it was pretty easy to trace the black greasy patch on the underside of the transmission to both the drive axle oil seals - they simply needed replacing.

THE TASK

I used the following:

8mm Spline Bit
8mm Hex Socket
17mm Hex Socket
Socket Ratchet Spanner
Torque Wrench
Socket Extension Bar
Small/Medium Heel Pry Bar or Seal Puller Tool
Seal Press or 38-40mm socket
Rubber Mallet
2 x Radial Shaft Seals (Porsche OEM Part number 016 409 399 B)
1 x Large Zip Tie or Length Of String/Rope
Spray Degreaser
Oil Drain Pan.
Stiff Scrubbing Brush
Axle Stands
Trolley Jack
Swepco 201 Gear Oil
Anti-seize thread lubricant
White Spirit
Karcher Powerwasher (optional)


THE HOW TO


(Amateur mechanic job time approx: 2-3 hours).

Start by raising the rear of the car and support on axle stands (the higher you can get the rear off the floor the easier the job becomes). As you can see from the photos below the seals on mine were leaking quite badly from both sides.


Depending how badly the seals have been leaking now might be the time to give the transmission underside a blast with the powerwasher and degreaser. The purpose of this is it makes the job a lot less messy and enables you to check for leaks once the job is complete.

Now follow my tutorial on how to remove the transmission oil, you will also need to refer to this when it comes to refilling the transmission once you've replaced the seals.

With the oil drained it's now time to remove drive axles where they meet the transmission. Start with the one that isn't under the exhaust (shown below) as it is the easier of the two and is a good way of getting a clear idea of what needs to be done when you start the slightly obstructed exhaust side.


To release the drive axle you need to undo 8 x 8mm spline screws. Make sure the spline bit goes in straight and not at an angle otherwise you risk rounding off the spline bit and probably the screw too. If you find it difficult to get a good angle on some of them then simply release the handbrake and rotate the wheel to improve the access.

With the spline screws removed you should now be able to move one end of the axle. Find a suitable place to hang the drive axle out of the way and cover the end with a plastic bag (this stops any grit getting stuck to grease in the universal joint).

The next step involves removing the flanged shaft. Start by poking an old screwdriver all the way through one of the empty spline screw holes, this stops the flange from moving when you release the 8mm hex screw from it's centre. Use a socket wrench with extension bar and 8mm hex bit to undo the centre screw as shown below.


Once the screw is removed the flanged axle should simply slide out. Give it a good clean and check there's no wear or rough areas on the axle near the flanged end.


Now we can see the large black coloured seal we are going to remove. I used a small heeled pry bar (or you can use a seal puller or other hooked instrument) to gently work around the seal and ease it out. Be careful when doing so as the blind side of the seal that you can't see contains and elasticated spring and it's easy to leave this behind in the transmission. Keep at it and the seal will eventually come out.

(Seal before removal)


(Blind-side of seal and elasticated spring)


(Seal removed)


Once removed it's a good idea to thoroughly clean the area so that no grit or muck enters the transmission when you come to install the new seal.

Here you can see the new seal (left) alongside the old seal (right)


You are now ready to install the new seal. Before you do so, take note of the small raised lip (see arrow below) that the new seal must press up against inside the seal hole. Now take a small amount of white spirit and lightly rub some of it around the outer edge of the black seal (this aids fitting and will shortly evaporate). Now press the seal squarely into the hole making sure the spring is facing in towards the transmissions internals. Now take a 38-40mm socket and a rubber mallet and gently tap the seal into place making sure it doesn't skew as you knock it in. Use your fingers every now and again to feel around the inside of the seal to see when it is fully pressed up against the lip on the inside.

Photo below shows a 38mm socket compared to the size of the seal.


And photo below shows the seal correctly fitted.


Now you can re-install the flanged axle and re-attach the drive axle shaft. You may also want to take this opportunity to refresh the grease in the CV joint at the end of the drive axle before reattachment.

Now all that remains is to repeat the procedure for the other side before refilling the transmission gear oil.

09/07/2010

How to remove and replace OPRV (Oil Pressure Relief Valve) on a Porsche 944

THE WHY

Since purchasing my 944 I'd always been aware of a slight fluid leak, but since none of the fluids (engine oil, power steering, water, brake fluid) seemed to be disappearing at any great rate and there were other more pressing issues I decided to put investigating it on the back burner.

Having now decided to tackle the problem I firstly discovered I actually had two fluid leaks, one from a power steering hose going from the reservoir to the pump which I dealt with right away by replacing the hose. The second however seemed to be coming from the engine but it was difficult to tell where from due to the oily grime all over the bottom of the engine and aluminium floor tray. So now the rest of the story follows how I went about identifying the cause of the oil leak and how the OPRV (Oil Pressure Relief Valve) fits into the story.

THE TASK

You'll need the following:

Karcher or other brand Water Pressure Washer
Gunk Spray Engine Degreaser
10mm socket
17mm socket (if you have the old style OPRV)
24mm socket (if you have the new style OPRV)
Ratchet socket wrench
Long socket wrench extension bar
2 x Axle Stands
Trolley Jack
Torque Wrench
Plenty of tissue or old rag

THE HOW TO

(Amateur mechanic job time: approx. 30mins - 1 hour)

Start by jacking up the front of the car and support on the first or ideally second stage of the axle stands.


Remove the seven 10mm bolts that secure the aluminium under-tray to the bottom of the car and remove the under-tray.


The picture above was taken after I'd degreased the underside of the car. I tried various methods of scrubbing, wiping and pressure steam cleaning but by far the best was pressure washing.

The best method I found was to let the engine run for 10 mins to warm it up, then spray Gunk Engine Degreaser over all the oily blackness you may have (Do not spray it near the belts or any bearings). Let the degreaser have 5-10 mins to take effect and then simply blast off with the water pressure washer (There's hardly any electrics on the bottom of the car but avoid them at all costs). Spraying the washer in quick bursts is the best method. Repeat as necessary and wipe down anything that looks oily, not forgetting to also clean all the oil of the under-tray too.

Now you have a clean canvas to identify your leak. Unless the leak is bad you probably won't be able to see it straight away, so this is where some patience comes in. Either leave it jacked up over night and see if you can identify a drip in the morning or re-attach the under-tray and do a few miles to put the engine under load which usually force the oil out of the place it is escaping. When you jack the car up again, you'll be able to see the area where the oil is dropping on the under-tray and then just trace it back up into the engine well.

The oil on mine was falling onto the left hand-side of the under-tray so I started to investigate in this area as shown my the orange arrow below.


This is where I found a drip coming off the end of the OPRV (Oil Pressure Relief Valve) nut.

Here's a couple of photos to show you what to look for (The nut has been removed but you can see the port it screws into)



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THE OPRV - here's where it gets complicated:

83-86 models will have a 17mm or 24mm nut
87 models onwards will and should always be 24mm.

Picture shows the difference between the 24mm on the left, 17mm on the right.


The 17mm nut may also look like this one below as well (photo taken from another Porsche source)


If you have the 17mm nut then you have the OLD discontinued OPRV, which can look like one of the two versions shown below (Difference is in the style of the nut and and piston). There are 4 pieces to each version, the nut, aluminium washer, spring and piston.



From the 87 model onwards a new OPRV was produced along with a retro-fit upgrade for people with the old style valve.

Here's the NEW retro-fit valve (944 107 035 11) for 83-86 models


And here's the one (944 107 035 02) for 87 models onwards


 And here they are side by side, 83-86 on left, 87 on right. (Main differences are in overall in length and the taper on the thread).


Both these newer style valves are serviceable to a degree in that you can replace the external and internal O-rings using this procedure below which was posted by a kind chap on the PelicanParts forums. Note valve type A requires two different size O-rings for the internal and external, whereas type B uses the same size O-ring for the internal and external.





The photo below shows what one of the newer OPRV's looks like when you take it apart. Note the aluminium sealing ring far left, damaged black internal O-ring in the middle and what should be a thicker green O-ring at the end (also damaged). If you need to replace the entire valve they aren't cheap either, £250 from Porsche.


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OPRV removal

Take a 17mm or 24 mm and socket extension bar that should be long enough to enable you to ratchet it from inside the wheel arch.



Once I had it removed I ended up with this


Notice the small nut that was inside the piston that some previous enterprising owner/mechanic had used as a space packer. I also found the spring to be 3-4 coils shorter than it should be, so who even knows what vehicle it was from. So not only did I have a leak from ORPV, I now had to replace the OPRV and at £250 that's quite a hit.

So here we are the OLD alongside the NEW




Installing the new OPRV is the reverse of removal, making sure you use a new aluminium sealing ring and lightly oil the o-ring and length of the valve to aid it's insertion. You should then use a Torque wrench to tighten to 45Nm.

Finally re-install the under-tray, run the car making sure the oil pressure gauge doesn't exhibit any strange behaviour and you're done...........well almost.

After doing all this I still found I had more oil leak coming from the same area, it now looks likely it's the gaskets for the Oil Cooler that the OPRV screws into. This looks a bit of an ugly job and not having the time to do it I'm going to get a mechanic to sort it out. For anyone that wants a go here's the procedure and here's another.

Finally here's the Porsche bulletin that goes into a few pages of detail on the OPRV. (Click the pictures for larger versions)