GT3 Centrelock instructions?
Discussion
Firstly, if you have 500Nm written on the centre nuts, get them changed as there was a recall a while back and replacements have NO torque setting on them.
You need special socket 000 721 979 60, which should be with the car. You'll also need some decent ¾" drive tools.
Removal:
Wind some insulating tape onto a flat blade screwdriver and remove the centre cap.
Grease the 'O' ring on the socket and push it onto the nut as far as it will go.
You will need an assistant inside the car with foot on the brake pedal, since the force needed to unscrew the nut is considerable. Make sure the socket remains fully engaged during the unscrewing process.
Once loose, jack the car up, undo the nut completely and withdraw the wheel. Take care you don't damage the brake rotor or calliper when doing so. Tool 000 721 979 40 is a wheel removal guide to facilitate this.
Ensure the nut is set down on its back so that the conical washer and thread don't get dirty.
Replacement:
Check all parts for wear and damage. Apply some aluminium paste on the nut thread. Carefully refit the wheel. Insert the centre nut into the socket and refit it vertically, screwing it on by hand at first. Tighten the nut with a suitable torque wrench using the following 3 step procedure with foot on the brake again:-
Step 1. Tighten the nut to 600Nm.
Step 2. Loosen the nut by 1/6th turn.
Step 3. Finally re-tighten the nut to 600Nm.
This all requires considerable force and you should make sure the car is very secure and will not slip off the jack whilst doing this!
After final tightening make sure the locking pin is engaged correctly in the centre bolt. It is a sprung fixing and must end up flush with the inner toothing of the nut - this is most important to prevent the nut loosening off again. If the pin is not seated correctly you should reach in and turn it slightly, use circlip pliers or something, until it clicks into place.
Refit the cap locating the lug in the machined slot in the nut and lower the car to the ground.
In practise, I use a ¾" drive 'T' bar and a long lever to remove the nut and a 300Nm torque wrench with a Sealey torque multiplier to tighten it.
Hope this helps.
You need special socket 000 721 979 60, which should be with the car. You'll also need some decent ¾" drive tools.
Removal:
Wind some insulating tape onto a flat blade screwdriver and remove the centre cap.
Grease the 'O' ring on the socket and push it onto the nut as far as it will go.
You will need an assistant inside the car with foot on the brake pedal, since the force needed to unscrew the nut is considerable. Make sure the socket remains fully engaged during the unscrewing process.
Once loose, jack the car up, undo the nut completely and withdraw the wheel. Take care you don't damage the brake rotor or calliper when doing so. Tool 000 721 979 40 is a wheel removal guide to facilitate this.
Ensure the nut is set down on its back so that the conical washer and thread don't get dirty.
Replacement:
Check all parts for wear and damage. Apply some aluminium paste on the nut thread. Carefully refit the wheel. Insert the centre nut into the socket and refit it vertically, screwing it on by hand at first. Tighten the nut with a suitable torque wrench using the following 3 step procedure with foot on the brake again:-
Step 1. Tighten the nut to 600Nm.
Step 2. Loosen the nut by 1/6th turn.
Step 3. Finally re-tighten the nut to 600Nm.
This all requires considerable force and you should make sure the car is very secure and will not slip off the jack whilst doing this!
After final tightening make sure the locking pin is engaged correctly in the centre bolt. It is a sprung fixing and must end up flush with the inner toothing of the nut - this is most important to prevent the nut loosening off again. If the pin is not seated correctly you should reach in and turn it slightly, use circlip pliers or something, until it clicks into place.
Refit the cap locating the lug in the machined slot in the nut and lower the car to the ground.
In practise, I use a ¾" drive 'T' bar and a long lever to remove the nut and a 300Nm torque wrench with a Sealey torque multiplier to tighten it.
Hope this helps.
TonyB66 said:
What a total PIA fitting/refitting the centre locks is. Can't really see what the on road benefit of having them in the first place is. Maybe just another way for Porsche to make sure you have to go back and see them for servicing.
It does seem odd that, given the palaver described, this set up even loses the only advantage centre locks have, speed of change. never mind the extra cost and risk.
I just can't understand why anyone would want this on a road car, or even why Porsche decided to do it.
Mermaid said:
Look good.
So, it's just for the looks then? Seems a lot of hastle for the sake of it.Imagine shopping around for N rated tyres and then finding that the fitters couldn't fit them.
They might be great, perhaps, if you are a trackday fan and have a choice of wheel/tyre combo/
Otherwise I can't see the point.
Regards the grease, this is not just for the threads, in fact the threads don't need much at all but you also need to have grease on the conical surface of the nut but only a thin coating. This is ok for a few removals of the wheel but you also need to know how to grease up the whole nut, fill the grease reservoirs etc. there is a Porsche procedure for this.
It's a time consuming PITA but do it once or twice and it's fairly easy.
It's a time consuming PITA but do it once or twice and it's fairly easy.
I love the look of the centre locks on the GTS. However I assume that if I have a puncture the Porsche appointed recovery service will know exactly what to do!!! Having no spare wheel a flat bed recovery truck will be needed and a trip to the local OPC or nearest tyre repair centre?
Any one have any experience of a puncture and resulting hassles with these wheels.
Look forward to your thoughts.
Any one have any experience of a puncture and resulting hassles with these wheels.
Look forward to your thoughts.
Rioja said:
I love the look of the centre locks on the GTS. However I assume that if I have a puncture the Porsche appointed recovery service will know exactly what to do!!! Having no spare wheel a flat bed recovery truck will be needed and a trip to the local OPC or nearest tyre repair centre?
The answer to your question is yes. If the bottle of gloop in the luggage compartment doesn't give you a tyre that you can drive on the Porsche Assist will send a low loader and take you to an OPC. If you were able to get a spare wheel to the car and have a sufficiently long bar that can handle the torque necessary to remove the wheels, there is some approved guidance to do a temporary change to get you to the OPC without a torque wrench.A short gentle road drive to a dealer or decent independent (whichever is closer) could safely be accomplished with torque well below the increased 600nm spec for track use. I have a PDF of the handbook (think it is the the US version, can't be bothered to get the one out of my car to see if it is the same) which details the emergency procedure for torquing to 100nm then further tightening according to the square and the chevron on the nut to get it tight enough subject to the caveat :
"Have the central bolt loosened again
immediately at your authorized Porsche
dealer and then tighten it to the
prescribed tightening torque of 370 ftlb.
(500 Nm) using a suitable torque wrench." {note : clearly predates the revision of the recommended torque from 500nm to 600nm}
Getting the wheel off and having a spare are the real trick.
Edited by DiscoColin on Monday 5th November 18:27
tonycordon said:
They might be great, perhaps, if you are a trackday fan and have a choice of wheel/tyre combo/
Otherwise I can't see the point.
Worse if you do track days are you're more likely to want to swap wheels, meaning you'd have to own one of the massive torque wrenches required. I understand one or two cars have lost these wheels on track and Porsche have refused to pay out. And you won't get the option to use 18s in winter either. A serious case of form over function. And I'd never buy a car with them.Otherwise I can't see the point.
spyderman8 said:
Worse if you do track days are you're more likely to want to swap wheels, meaning you'd have to own one of the massive torque wrenches required. I understand one or two cars have lost these wheels on track and Porsche have refused to pay out. And you won't get the option to use 18s in winter either. A serious case of form over function. And I'd never buy a car with them.
Had similar thoughts myself until I ended up owning a car with centre-locks. Now I like them. It's quite an impressive piece of engineering, actually.
And no you don't need a massive torque wrench, just the torque multiplier mentioned in my earlier post.
They do look the part but also save on unsprung weight, giving a slight performance advantage.
I'm sure if I set out to describe step by step removal/replacement of a normal 5 bolt wheel, it would sound equally daunting, but as someone has already said, it's easy once you've done it a couple of times.
Properly tightened and with the locking mechanism in place, the system is safe. Early failures may well have been as much due to incorrect fitting as insufficient tightening.
It would be a pity if people missed out on a nice car simply because they'd read bad press about centre-locks.
Edited by Lancerlot on Sunday 11th November 22:38
TonyB66 said:
What a total PIA fitting/refitting the centre locks is. Can't really see what the on road benefit of having them in the first place is. Maybe just another way for Porsche to make sure you have to go back and see them for servicing.
+1, Whats the point on a road car??! They may look nice, but sound fairly fragile, expensive and more hassle.
nickfrog said:
So how much rotational weight do you save with CL?
I always thought rotational weight saving was useful on the outside of the wheel (where rotational speed is the highest) but near the centre it had a negligeable effect. That's my cycling background for you !
Correct. centripital acceleration and gyroscopic inertia are the terms you're looking for. In the real world, CL wheels vs 5 stud will have very little meaningful difference using either of these measures.I always thought rotational weight saving was useful on the outside of the wheel (where rotational speed is the highest) but near the centre it had a negligeable effect. That's my cycling background for you !
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