In my quest to tighten up the handling on the 944, I bought a new Needle Bearing from Porsche in an attempt to eliminate the fore-aft play in the steering at the top universal joint.
The part number for the replacement is 477.419.059 and costs £88.86 posted from an OPC. Nothing like the effort required to actually remove the old one...
I began the process by reading section 48 of Porsche Workshop manual. It appeared a simple enough process but two things bothered me: firstly, it required a chisel to remove a shear bolt (which in my limited experience never "shear"; and secondly a drill to remove two screws from the ignition lock. I was bothered because a quick look under the dashboard made it quite obvious that whoever had written the manual hadn't performed this task - well not without a dashboard in place that's for sure. I was bothered before I'd even started.
Furthermore, the manual doesn't detail the replacement of this bearing at all - just the removal of the steering shaft & housing for replacement. While I wasn't needing to do that, I did certainly need to move the shaft rearwards into the cabin enough to detach the universal joint in the engine bay, and remove the old needle bearing assembly from inside the footwell. I couldn't see the need to remove the steering lock & ignition barrel, which left just three bolts and the shear bolt besides the universal joint.
And so I began by removing the universal joint bolt - this has to be removed completely from the joint to allow separation of the shaft and joint. It's a fiddly process made difficult by the proximity of the clutch cylinder directly above the joint - cursed engineers, they should be made to work on what they design! To make the separation easier I turned the wheels slightly to the left so the lower universal joint on the steering rack wouldn't prohibit the movement of the top joint away from the shaft. It did help, but not enough, the steering shaft was going to need moving back wards at least an inch. And so to underneath the dash...
The first two 12mm bolts that hold the housing are relatively easy to get to and remove, and so is the one 13mm bolt near the steering wheel end of the shaft. These can be removed laying on one's back looking like an idiot with feet on the top of the drivers seat. Speaking of the drivers seat, I found it helpful to slide it all the way back and recline it fully to reduce the headrush.
The steering wheel was removed in order to remove the trim panels exposing the inner goings on of the dash - the fascination was short lived as I progressed with the task at hand.
Things started to get to the "I wonder if I should bloody bother" stage when considering how to remove the shear bolt - which is much like a dome nut with no hex sides to secure a socket to. Why in Germany did Porsche think this was a good idea is anybody's guess - but I think it's completely unnecessary, however it must be removed in order for the steering shaft assembly to slide backwards and out from inside the dash. That is of course if the dash itself wasn't in the way...
As you can see from the pic above there's no way to pull the assembly backwards at all or gain access to the screws to drill out from below on the lock mechanism - without removing the dashboard, or as I decided to do - cut the aluminium and bend it like Beckham...
With that done, figuring out how to get access to the shear bolt in order to chisel it out became the next frustration. There's not enough space below to get a drill or Dremel in under the dash, nor can it be done from the front. It was time to remove the instrument cluster - something else not mentioned in the manual either. Danke mien Herr..
I begun to work out my frustration using a long screwdriver and a hammer, but after annoying the neighbors another problem was rearing its ugly head - the plate to which the shear bolt was attached was bending with every smack of the bolt. This bolt was not going to shear!
Getting desperate I headed to B&Q to buy a long narrow steel chisel, and an M8x20mm bolt to replace the shear bolt when I eventually got it off. I was hoping that one smack with the steel chisel would set the steering shaft free. But it was not to be - I became increasingly concerned that I was remodeling the steel plate and was never to see the shear bolt removed come hell or high water.
All that was left to do now was to have a cup of tea and practice some mind bending techniques on the shear bolt. The tea was refreshing enough to inspire a closer inspection of the offending bolt, which revealed that a washer existed - which I confess I had thought was one with the bolt. With renewed vigor I attacked the washer in an effort to destroy it and hopefully with it's destruction I could lever the bolt through the plate on the steering shaft housing. The plan worked - the shaft assembly was finally free:
With the whole steering shaft assembly now extracted from the beneath the dash, there was no need to drill out the two screws on the ignition lock as I had predicted, I could now begin the ardous task of getting the old needle bearing out of the bulkhead. Incidently the shear bolt was a doddle to unscrew by fingers!
The easiest way to do this was to use pliers to rip off the rubber flanges exposing the needle bearing case, and then using a crowbar to hammer it out. There's a second steel sleeve encapsulated in rubber that can be worked free with a long thin screwdriver, which leaves the outer rubber case easy enough to pop out of the bulkhead:
Comparing the old with the new:
Greasing up the sides of the new bearing I found the easiest way to press it into the bulkhead was with the steering shaft. Before securing the bolts under the dash, it was necessary to re-attach the universal joint. Be sure to line the recess in the end of the steering shaft up with the bolt hole before proceeding with the bolts in the cabin.
Then it was a matter of straightening the mounting plate; bolting everything up again and reassembling the dash instrument cluster and trim. Nightmare job over.
The part number for the replacement is 477.419.059 and costs £88.86 posted from an OPC. Nothing like the effort required to actually remove the old one...
I began the process by reading section 48 of Porsche Workshop manual. It appeared a simple enough process but two things bothered me: firstly, it required a chisel to remove a shear bolt (which in my limited experience never "shear"; and secondly a drill to remove two screws from the ignition lock. I was bothered because a quick look under the dashboard made it quite obvious that whoever had written the manual hadn't performed this task - well not without a dashboard in place that's for sure. I was bothered before I'd even started.
Furthermore, the manual doesn't detail the replacement of this bearing at all - just the removal of the steering shaft & housing for replacement. While I wasn't needing to do that, I did certainly need to move the shaft rearwards into the cabin enough to detach the universal joint in the engine bay, and remove the old needle bearing assembly from inside the footwell. I couldn't see the need to remove the steering lock & ignition barrel, which left just three bolts and the shear bolt besides the universal joint.
And so I began by removing the universal joint bolt - this has to be removed completely from the joint to allow separation of the shaft and joint. It's a fiddly process made difficult by the proximity of the clutch cylinder directly above the joint - cursed engineers, they should be made to work on what they design! To make the separation easier I turned the wheels slightly to the left so the lower universal joint on the steering rack wouldn't prohibit the movement of the top joint away from the shaft. It did help, but not enough, the steering shaft was going to need moving back wards at least an inch. And so to underneath the dash...
The first two 12mm bolts that hold the housing are relatively easy to get to and remove, and so is the one 13mm bolt near the steering wheel end of the shaft. These can be removed laying on one's back looking like an idiot with feet on the top of the drivers seat. Speaking of the drivers seat, I found it helpful to slide it all the way back and recline it fully to reduce the headrush.
The steering wheel was removed in order to remove the trim panels exposing the inner goings on of the dash - the fascination was short lived as I progressed with the task at hand.
Things started to get to the "I wonder if I should bloody bother" stage when considering how to remove the shear bolt - which is much like a dome nut with no hex sides to secure a socket to. Why in Germany did Porsche think this was a good idea is anybody's guess - but I think it's completely unnecessary, however it must be removed in order for the steering shaft assembly to slide backwards and out from inside the dash. That is of course if the dash itself wasn't in the way...
As you can see from the pic above there's no way to pull the assembly backwards at all or gain access to the screws to drill out from below on the lock mechanism - without removing the dashboard, or as I decided to do - cut the aluminium and bend it like Beckham...
With that done, figuring out how to get access to the shear bolt in order to chisel it out became the next frustration. There's not enough space below to get a drill or Dremel in under the dash, nor can it be done from the front. It was time to remove the instrument cluster - something else not mentioned in the manual either. Danke mien Herr..
I begun to work out my frustration using a long screwdriver and a hammer, but after annoying the neighbors another problem was rearing its ugly head - the plate to which the shear bolt was attached was bending with every smack of the bolt. This bolt was not going to shear!
Getting desperate I headed to B&Q to buy a long narrow steel chisel, and an M8x20mm bolt to replace the shear bolt when I eventually got it off. I was hoping that one smack with the steel chisel would set the steering shaft free. But it was not to be - I became increasingly concerned that I was remodeling the steel plate and was never to see the shear bolt removed come hell or high water.
All that was left to do now was to have a cup of tea and practice some mind bending techniques on the shear bolt. The tea was refreshing enough to inspire a closer inspection of the offending bolt, which revealed that a washer existed - which I confess I had thought was one with the bolt. With renewed vigor I attacked the washer in an effort to destroy it and hopefully with it's destruction I could lever the bolt through the plate on the steering shaft housing. The plan worked - the shaft assembly was finally free:
With the whole steering shaft assembly now extracted from the beneath the dash, there was no need to drill out the two screws on the ignition lock as I had predicted, I could now begin the ardous task of getting the old needle bearing out of the bulkhead. Incidently the shear bolt was a doddle to unscrew by fingers!
The easiest way to do this was to use pliers to rip off the rubber flanges exposing the needle bearing case, and then using a crowbar to hammer it out. There's a second steel sleeve encapsulated in rubber that can be worked free with a long thin screwdriver, which leaves the outer rubber case easy enough to pop out of the bulkhead:
Upon inspection of the needle bearing I finally felt like this job was worth doing - it was completely knackered:
Comparing the old with the new:
Greasing up the sides of the new bearing I found the easiest way to press it into the bulkhead was with the steering shaft. Before securing the bolts under the dash, it was necessary to re-attach the universal joint. Be sure to line the recess in the end of the steering shaft up with the bolt hole before proceeding with the bolts in the cabin.
Then it was a matter of straightening the mounting plate; bolting everything up again and reassembling the dash instrument cluster and trim. Nightmare job over.
Hey, nice job and thanks for writing this up. I think I may have to do it too...did it actually improve your steering at all? I have been chasing a dead zone in the centre of my 951 steering for a while - new u-joints, tie rods, rebuilt rack etc...still there. I noticed I have some axial play in the column (i.e. I can push/pull the steering wheel in/out with a clunk). I wonder if this could be the solution? Thanks!
ReplyDeletesame for me! same axial play..ouch.
ReplyDeleteif you say all those replacements didn't solve the issue...what else is there apart from the needle baring left to check?
I appear to have TWO shear bolts holding the steering shaft in place! they are a real pain to remove 3 hours so far!!
ReplyDelete