924Board.org

[-nick]

Just for the record, what is needed to swap the 924S/ '86 951 rear alloy trailing arms onto a 5-lug car?

I'm thinking:
-arms
-spring plates (since the arms bolt to them slightly differently)
-rotor (?)
-axles
-stub axles
-hubs & lugs
-do something about the shocks
-handbrake shoes/parts (do I need the cable too?)

Is that it? Do the stock rear M471 calipers bolt right up?

nick

[ic932]

To use the alloy arms you need late spring plates and late cables and late rear shocks.These later style shocks have a larger bolt hole in the bottom and the regular bolt hole in the top and are 100% bolt on.You will also need late drive shafts.

You can use your existing shoes,rotors and calipers.If the half-shafts and hubs don't come complete with the arms then I'd walk away.I've been told that pressing the hubs out of the arms damages the bearings so insist that the arms come complete with hub and half-shaft.

[gohim]

The wheel hubs are the same design as the 924/931/early 944 design, and they are not pressed onto the wheel axles. The wheel axles are the same design as the earlier cars as well.

Removing the wheel axles from the trailing arms/bearings does not damage them. The wheel bearings are a sealed design, and are not servicable as the earlier design. So there is no reason to remove the bearings from the trailing arms, unless they are going to be replaced anyway.

The wheel axles, wheel hubs and cv axles are all different from those used on the earlier cars because of the additional track width built into the alloy trailing arms.

If you are considering conversion, I would try to get the parts all together, because you are going to need all the parts, and not for any other reason.

[ic932]

The hubs and wheel axles carry 951 part numbers and are not the same design as the 931 parts and are not interchangable in anyway.

[Manning]

Yes, as IC932 pointed out the 924S and 951 and late 944s share rear hubs and they are not interchangable with earlier cars.

Gohim makes a very good point that you should try and find the rear suspension as a complete unit
_________________
Michael Manning
1988 924S Undergoing weight loss program

[-nick]

So the original list above is complete? Though it looks like the rear rotors are the same too.

I don't have a truck to move the rear suspension as one unit. The components are quite a bit smaller than the entire torsion bar assembly.

nick

[gohim]

The rear rotors are the same, if you are buying used ones, make sure that thry will be thick enough to reuse, they only have 1-1.5mm of wear surface when they are new.

The parking brake assemblies are the same as well. parking brake shoes are expensive for some reason (cost is more than brake pads), so make sure they are good).

Parking brake cables are definitely longer on the alloy trailing arm cars (probably due to the increase in track width, than cars with steel trailing arms and rear disc brakes). I do not know if you can get away with reusing the shorter parking brake cable from a steel trailing arm car with rear disc brakes.

After tearing apart my 83 944 parts car, I found the the rear torsion bar assembly really isn't as large or heavy as I thought it would be when I first thought.

While it could fit in the back seat of a car (or the rear of your 924), fully assembled, it would be easier if you could buy the thing whole, then remove the rotors, calipers, and cv axles to reduce the handling weight and awkwardness.

This would leave the hard to align, and reindex trailing arms, spring plates, and torsion bars still together, and give you a place to start after you get the thing remounted in your car.

You also get the heavier torsion bars, and gain the rear sway bar mounts (if your current rear assembly does not have them).

[ic932]

One other thing to take into account is wheel offset.If you are already using rims without the 22mm spacer to make them fit then the chances are they won't work with the alloy arms.

[Manning]

I'm not sure what you mean by that. What model year is nick's car? Didn't the later 924s use the same or close to the same offset as the 924S? So basically it was this spacer that allowed the use of higher offset wheels?

Also, don't you also need the torsion bar tube/rear axle carrier? I mean it is a different part number for the alloy arm setup. If so then this again speaks to what Gohim mentioned about trying to find a complete rear end and keep as much as possible assembled.
_________________
Michael Manning
1988 924S Undergoing weight loss program

[gohim]

I think ic932 may be suggesting that a problem could occur IF the rear wheels have been replaced with wheels of a different offset, and/or diameter, and/or width, that require the removal/deletion of the 21mm rear wheels spacers because of clearance problems to the outside. Remember, the alloy trailing arms have the addition track width built into them, to allow the deletion of the spacers, and still have the same increased track width as the earlier car with the spacers installed.

The spacers actually increase the rear track width of the four wheel disc brake cars over that of the disc/drum brake cars. I suspect (without going out to try it), that the stock five bolt wheels (basketweave or phone dials) will still clear in the rear (both to the inside and outside, and the brake calipers) if you remove the spacers and try to bolt the wheels directly to the wheel hubs (of course you would need open ended lugs nuts because of the length of the wheel studs that would be exposed).

[-nick]

Thanks guys- that's what I was looking for! I should have qualified this is for an '80 931 in my case, so I can't swap torsion tubes even if I wanted. Any non-snailshell cars would be better off swapping the whole assembled torsion tube & rear suspension.

Just to recap, the list looks like:

87-88 924S or 86 951 donor:
-rear control arms
-spring plates
-axles
-stub axles
-hubs
-use late shocks & open up upper shock bolt hole for larger nut&bolt
-hand cable

Again, this is on an M471/ 4-wheel disc equiped 924 to start with. Wheel offsets aren't a problem as long as you use the standard 52mm 5-lug 924 offset.

There was someone local parting an '86 951, which was the reason for the inquiry. Unfortunately, it looks like they're selling the car as a whole (well, unfortunate for me, good for the car!).

Thanks for the replies,
nick

[ic932]

Nick just one last thing.The late style shock whether it's koni,sachs or bilstein have two different size mounting bushes.The top one is identical in size to the regular 931,924 and early 944.The lower one is larger.This is a bolt on affair there's no need to ream the top mounting to accomadate a larger bolt.From the earliest 924 to the latest 968 this mounting point is the same.

[gohim]

What are they trying to get for the whole car?

Too bad they are trying to sell it whole, and you don't/want the whole car.

You could always buy it, take what you need, and resell the rest. I have done that a couple of times before. You could also ask the Seller to hold your name and phone number incase they change their mind about how they are getting rid of he car, or pass your name and number to the Buyer (who may not have a need for the running gear).

I would also like to point out that the 86 is the perfect year to swipe the front struts from if you are considering a swap to 951 brakes, since the front track is conpatible with the 924, and early 944 since the 86 951 came with steel front lower arms. This was changed on the 87 951. The 86 is the best year 951 to get the front suspension and brake parts from.

[-nick]

Don't know what they want for the whole car. I have little space and even less time, or else I'd jump on it.

I forgot about the braking possibility. Definitely something to keep in mind.

PS- thanks for the heads-up on the later shocks. That makes the whole mess a bolt-on affair. Much easier than I thought.

nick